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The Building Regulations 2010
In effect from 1 October 2010
L1B Conservation of fuel and power
in existing dwellings
L1B APPROVEDDOCUMENT
Conservation of fuel and power
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MAIN CHANGES IN THE
2010 EDITION1 This Approved Document L1B came into force
on 1 October 2010 in support of the Buildingand Approved Inspectors (Amendment)Regulations 2010 SI 2010 No 719 The mainchanges to the legal requirements and the
supporting guidance in this edition of Approved Document L1B are as follows
Changes in the legal requirements
2 The exemption from the energy efficiencyprovisions for extensions consisting of aconservatory or porch is amended to grantthe exemption only where any existing wallswindows or doors are retained or replaced ifremoved and where the heating system ofthe building is not extended into theconservatory or porch
3 The list of work in Schedule 4 (work thatneed not be notified to building control) isamended to include the installation ofthermal insulation in a roof space or loftspace where this is the only work carried outand the work is not carried out to complywith any requirement in the BuildingRegulations
Changes in the technical guidance
4 In this Approved Document the guidance isgenerally based upon an elemental approachto demonstrating compliance with additionalguidance that provides greater flexibility Themain technical changes comprise a generalstrengthening of energy efficiency standardsthat are considered reasonable for work onthermal elements controlled fittings andcontrolled services in existing dwellings
5 Amended guidance is given for historic andtraditional buildings which may have anexemption from the energy efficiencyrequirements or where special considerationsapply
6 Amended guidance is given where anextension is a conservatory or porch that isnot exempt from the energy efficiencyrequirements
7 The guidance for the renovation of a thermalelement through the provision of a new layeror through the replacement of an existinglayer has been expanded
8 Guidance is provided for swimming poolbasins (walls and floor) in existing dwellings
Main changes made by the
2010 and 2011 amendmentsThis 2010 edition incorporating the further2010 amendments reflects the changes madeas a result of the Building Regulations 2010Building Approved inspector etc Regulationsand the Building (Amendment) Regulations
2011 The changes mainly reflect regulationnumber changes as a result of re-ordering Therehave been no amendments to the substantiverequirements in Schedule 1(ie Parts A to P) ofthe Building Regulations
Please note the simplification of the definitionof lsquoroom for residential purposesrsquo in regulation2 of the Building Regulations 2010 and theamendment of the definition of ldquorenovationrdquoin regulation 2(1) of the Building (Amendment)Regulations 2011 Please also note that L1(c) hasnow become regulation 40
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Approved Document L1B Conservation of fuel and power
PAGE
Section 1 Introduction 2
What is an Approved Document 2
Consideration of technical risk 2
How to use this Approved Document 2
Where you can get further help 3
Responsibility for compliance 3
Section 2 The requirements 4
LIMITATION ON REQUIREMENTS 6
Section 3 General guidance 7
Key terms 7
Types of work covered by this
Approved Document 8Dwellings within the scope of theenergy efficiency requirements 8
Dwellings exempt from the energyefficiency requirements 8
Notification of work covered by theenergy efficiency requirements 9
Materials and workmanship 10
The Workplace (Health Safety andWelfare) Regulations 1992 11
Section 4 Guidance relating tobuilding work 12
THE EXTENSION OF A DWELLING 12
Reference method 12
Optional approaches with moredesign flexibility 12
Conservatories and porches 12
Swimming pool basins 13
MATERIAL CHANGE OF USE ANDCHANGE OF ENERGY STATUS 13
Material change of use 13
Change of energy status 13
Option providing more design flexibility 14
WORK ON CONTROLLED FITTINGS AND SERVICES 14
Controlled fittings 14
Controlled services 15
COMMISSIONING OF FIXED BUILDINGSERVICES 15
PAGE
Section 5 Guidance on thermal elements 17
THE PROVISION OF THERMAL ELEMENTS 17
U-values 17
Continuity of insulation and airtightness 17
RENOVATION OF THERMAL ELEMENTS 17
RETAINED THERMAL ELEMENTS 18
Section 6 Consequential improvements toenergy performance 19
Section 7 Providing information 20
Appendix A Work to thermal elements 21
Appendix B Documents referred to 24
Appendix C Standards referred to 25
Index 26
Contents L1BN L I N E V E R I N
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L1B
Conservation of fuel and power Approved Document L1B
2
Section 1 Introduction
What is an Approved Document
11 This Approved Document which takeseffect on 1 October 2010 has been approvedand issued by the Secretary of State to providepractical guidance on ways of complying with the
energy efficiency requirements (see Section 2)and regulation 7 of the Building Regulations 2010(SI 20102214) for England and Wales Regulation2(1) of the Building Regulations defines theenergy efficiency requirements as therequirements of regulations 23 26 28 29 40and Part L of Schedule 1 The BuildingRegulations 2010 are referred to throughout theremainder of this Document as lsquothe BuildingRegulationsrsquo
12 The intention of issuing Approved Documentsis to provide guidance about compliance withspecific aspects of building regulations in some
of the more common building situations Theyset out what in ordinary circumstances may beaccepted as reasonable provision for compliancewith the relevant requirement(s) of buildingregulations to which they refer
13 If guidance in an Approved Documentis followed there will be a presumption ofcompliance with the requirement(s) covered bythe guidance However this presumption can beoverturned so simply following guidance doesnot guarantee compliance for example if theparticular case is unusual in some way thenlsquonormalrsquo guidance may not be applicable It is
also important to note that there may well beother ways of achieving compliance with therequirements There is therefore no obligationto adopt any particular solution contained inthis Approved Document if you would preferto meet the relevant requirement in someother way Persons intending to carry outbuilding work should always check with theirbuilding control body either the local authorityor an approved inspector that their proposalscomply with building regulations
14 It is important to note that this ApprovedDocument as well as containing guidance also
contains extracts from the Regulations Suchregulatory text must be complied with as statedFor example the requirement that fixed building services must be commissioned (regulation 44)is a regulatory requirement There is therefore noflexibility to ignore this requirement neither cancompliance with this particular regulation bedemonstrated via any route other than that setout in regulation 44
15 The guidance contained in this ApprovedDocument relates only to the particularrequirements of the Building Regulations that thedocument addresses (set out in Section 2)
However building work may be subject to morethan one requirement of building regulations Insuch cases the work will also have to comply
with any other applicable requirements ofbuilding regulations
16 There are Approved Documents that giveguidance on each of the Parts of Schedule 1 andon regulation 7 A full list of these is provided at
the back of this document
Consideration of technical risk
17 Building work to existing dwellings mustsatisfy all the technical requirements set outin regulations 23 22 28 and 29 of and Schedule1 to the Building Regulations When consideringthe incorporation of energy efficiency measuresin dwellings attention should alsobe paid in particular to the need to comply withPart B (fire safety) Part C (site preparation andresistance to contaminants and moisture) Part E(resistance to the passage of sound) Part F
(ventilation) paragraph G3 (hot water supply andsystems) Part J (combustion appliances and fuelstorage systems) and Part P (electrical safety)of Schedule 1 to the Building Regulations aswell as Part L The adoption of any particularenergy efficiency measure should not involveunacceptable technical risk of for instanceexcessive condensation Designers and buildersshould refer to the relevant Approved Documentsand to other generally available good practiceguidance to help minimise these risks
How to use this Approved Document
18 This Approved Document is subdividedinto seven sections as detailed below Thesesections are followed by supporting appendices
This introductory section sets out the generalcontext in which the guidance in this ApprovedDocument must be considered
Section 2 sets out the relevant legal requirementscontained in the Building Regulations
Section 3 contains general guidance includingthe definition of key terms the types of buildingwork covered by this Approved Documentthe types of building work that are exempt
procedures for notifying work materials andworkmanship and health and safety issues
Section 4 gives guidance on reasonableprovision for various types of building work
Section 5 deals with the particular case of workto thermal elements
Section 6 gives guidance in support of therequirement for consequential improvements for buildings over 1000 m2
Section 7 describes the information that shouldbe provided to occupiers to help them achievereasonable standards of energy efficiency inpractice
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Approved Document L1B Conservation of fuel and power
INTRODUCTION L1B
19 In this document the following conventionshave been adopted to assist understanding andinterpretation
a Texts shown against a green background areextracts from the Building Regulations 2010(SI 20102214) or Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)and set out the legal requirements that relateto compliance with the energy efficiency requirements of building regulations As statedpreviously there is no flexibility in respect ofsuch text it defines a legal requirement notguidance for typical situations It should alsobe remembered that as noted abovebuilding works must comply with all the otherapplicable requirements of building regulations
b Key terms are defined in paragraph 31 andare printed in bold italic text
c Details of technical publications referred toin the text of this Approved Document will be
given in footnotes and repeated as referencesat the end of the document A reference to apublication is likely to be made for one of twomain reasons The publication may containadditional or more comprehensive technicaldetail which it would be impractical toinclude in full in the Approved Document butwhich is needed to fully explain ways ofmeeting the requirements or it is a source ofmore general information The reason for thereference will be indicated in each case Thereference will be to a specified edition of thedocument The Approved Document may beamended from time to time to include newreferences or to refer to revised editionswhere this aids compliance
d Additional commentary in italic text appearsafter some numbered paragraphs Thiscommentary is intended to assist understandingof the immediately preceding paragraph orsub-paragraph or to direct readers tosources of additional information but is notpart of the technical guidance itself
Where you can get further help
110 If you do not understand the technical
guidance or other information set out in this Approved Document and the additional detailedtechnical references to which it directs you thereare a number of routes through which you canseek further assistance
bull the Department for Communities andLocal Government websitewwwcommunitiesgovuk
bull the Planning Portal websitewwwplanningportalgovuk
bull if you are the person undertaking the buildingwork you can seek assistance either from
your local authority building control service orfrom your approved inspector (depending onwhich building control service you are using
bull persons registered with a competent personself-certification scheme may be able to gettechnical advice from their scheme operator
bull if your query is of a highly technical natureyou may wish to seek the advice of aspecialist or industry technical body forthe relevant subject
Responsibility for compliance111 It is important to remember that if youare the person (eg designer builder installer)carrying out building work to which anyrequirement of building regulations applies youhave a responsibility to ensure that the workcomplies with any such requirement The buildingowner may also have a responsibility for ensuringcompliance with building regulation requirementsand could be served with an enforcement noticein cases of non-compliance
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Conservation of fuel and power Approved Document L1B
L1B
21 This Approved Document which takeseffect on 1 October 2010 deals with the energyefficiency requirements in the BuildingRegulations Regulation 2(1) of the BuildingRegulations defines the energy efficiency requirements as the requirements of regulations23 26 28 40 and Part L of Schedule 1 Theenergy efficiency requirements relevantto existing dwellings are in regulations 23 28 29and 40 of and Part L of Schedule 1 to thoseRegulations as set out below
Requirements relating to thermal elements ndash Regulation 23
(1) Where a person intends to renovate a thermal element
such work shall be carried out as is necessary to ensure that the
whole thermal element complies with the requirements of
paragraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the new thermal
element shall comply with the requirements of paragraph L1(a)
(i) of Schedule 1
Consequential improvements to energy performance
Regulation 28
(1) Paragraph (2) applies to an existing building with a total
useful floor area over 1000 m2 where the proposed building
work consists of or includesmdash
(a) an extension
(b) the initial provision of any fixed building services or
(c) an increase to the installed capacity of any fixed
building services
(2) Subject to paragraph (3) where this paragraph applies
such work if any shall be carried out as is necessary to ensure
that the building complies with the requirements of Part L of
Schedule 1
(3) Nothing in paragraph (2) requires work to be carried out if
it is not technically functionally or economically feasible
Energy performance certificates ndash Regulation 29
(1) This regulation applies wheremdash
(a) a building is erected or
(b) a building is modified so that it has a greater or fewer
number of parts designed or altered for separate use than it
previously had where the modif ication includes the provision
or extension of any of the fixed services for heating hot water
air conditioning or mechanical ventilation
(2) The person carrying out the work shallmdash
(a) give an energy performance certificate for the building
to the owner of the building and
(b) give to the local authority notice to that effect
including the reference number under which the energy
performance certificate has been registered in accordance withregulation 17F(4)
Section 2 The requirements
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Approved Document L1B Conservation of fuel and power
THE REQUIREMENTS L1B
Energy performance certificates ndash Regulation 29 (continued)
(3) The energy performance certificate and notice shall be
given not later than f ive days after the work has been completed
(4) An energy performance certificate mustmdash
(a) express the asset rating of the building in a way
approved by the Secretary of State under regulation 24
(b) include a reference value such as a current legal
standard or benchmark
(c) be issued by an energy assessor who is accredited to
produce energy performance certificates for that category of
building and
(d) include the following informationmdash
(i) the reference number under which the certificate
has been registered in accordance with regulation 30(4)
(ii) the address of the building
(iii) an estimate of the total useful floor area of the
building
(iv) the name of the energy assessor who issued it
(v) the name and address of the energy assessorrsquos
employer or if he is self-employed the name under which he
trades and his address
(vi) the date on which it was issued and
(vii) the name of the approved accreditation scheme of
which the energy assessor is a member
(5) The energy performance certificate must be accompanied
by a recommendation report containing recommendations for
the improvement of the energy performance of the building
issued by the energy assessor who issued the energy
performance certificate
(6) Certification for apartments or units designed or alteredfor separate use in blocks may be basedmdash
(a) except in the case of a dwelling on a common
certification of the whole building for blocks with a common
heating system or
(b) on the assessment of another representative apartment
or unit in the same block
(7) Wheremdash
(a) a block with a common heating system is divided into
parts designed or altered for separate use and
(b) one or more but not all of the parts are dwellings
certification for those parts which are not dwellings may be based on a common certification of all the parts which are not
dwellings
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L1B THE REQUIREMENTS
6
Conservation of fuel and power Approved Document L1B
Requirement Limits on application
Schedule 1 ndash Part L Conservation of fuel and power
L1 Reasonable provision shall be made for the conservation of
fuel and power in buildings by
(a) limiting heat gains and lossesmdash
(i) through thermal elements and other parts of the
building fabric and
(ii) from pipes ducts and vessels used for space
heating space cooling and hot water services
(b) providing fixed building services whichmdash
(i) are energy efficient
(ii) have effective controls and
(iii) are commissioned by testing and adjusting as
necessary to ensure they use no more fuel and power than is
reasonable in the circumstances and
Regulation 40 providing to the owner sufficient informationabout the building the fixed building services and their
maintenance requirements so that the building can be operated
in such a manner as to use no more fuel and power than is
reasonable in the circumstances
LIMITATION ON REQUIREMENTS
22 In accordance with regulation 8 of theBuilding Regulations the requirements in Parts Ato D F to K and N (except for paragraphs G2 H2and J7) of Schedule 1 to the Building Regulations
do not require anything to be done except for thepurpose of securing reasonable standards ofhealth and safety for persons in or about buildings(and any others who may be affected by buildingsor matters connected with buildings)
23 Paragraph G2 is excluded as it deals withwater efficiency and paragraphs H2 and J7 areexcluded from regulation 8 because they dealdirectly with prevention of the contamination ofwater Parts E and M (which deal respectivelywith resistance to the passage of sound andaccess to and use of buildings) are excludedfrom regulation 8 because they address the
welfare and convenience of building users Part Lis excluded from regulation 8 because it addressesthe conservation of fuel and power
24 In addition regulation 4(2) of the BuildingRegulations states that where the work is beingcarried out in order to comply with regulation 23(requirements relating to renovation or replacementof a thermal element ) regulation 22 (requirementsrelating to a change of a buildingrsquos energy status)or regulation 28 ( consequential improvements to energy performance) and is not a materialalteration it need comply only with the requirementsof Part L
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Approved Document L1B Conservation of fuel and power
L1B
Key terms
31 The following are key terms used in thisdocument
BCB means Building Control Body a local
authority or an approved inspectorCommissioning means the advancement ofa fixed building service following installationreplacement or alteration of the whole or partof the system from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances without prejudice to the needto comply with health and safety requirementsFor each system commissioning includessetting-to-work regulation (that is testing andadjusting repetitively) to achieve the specified
performance the calibration setting up andtesting of the associated automatic controlsystems and recording of the system settingsand the performance test results that have beenaccepted as satisfactory
Consequential improvements means thoseenergy efficiency improvements required byregulation 28
Controlled service or fitting means a service orfitting in relation to which Part G (sanitation hotwater safety and water efficiency) H (drainageand waste disposal) J (combustion appliancesand fuel storage systems) L (conservation of fuel
and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement
Dwelling means a self-contained unit includinga house or a flat designed to be used separatelyto accommodate a single household ( Rooms for residential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings)
Energy efficiency requirements means therequirements of regulations 23 26 28 29 and40 of and Part L of Schedule 1 to the BuildingRegulations
In respect of existing dwellings the applicable requirements consist of Part L and regulations 23 38 and 40
Fixed building services means any part of orany controls associated with
a fixed internal or external lighting systems butdoes not include emergency escape lightingor specialist process lighting or
b fixed systems for heating hot water airconditioning or mechanical ventilation
Room for residential purposes means a room ora suite of rooms which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel anhotel a boarding house a hall of residence or a
residential home but does not include a room in ahospital or other similar establishment used forpatient accommodation
lsquo Renovationrsquo in relation to a thermal elementmeans the provision of a new layer in the thermalelement (other than where that new layer isprovided solely as a means of repair to a flatroof) or the replacement of an existing layer butexcludes decorative finishes and lsquorenovatersquo shallbe construed accordingly
Simple payback means the amount of time itwill take to recover the initial investment through
energy savings and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT When making thiscalculation the following guidance should be used
a the marginal additional cost is the additionalcost (materials and labour) of incorporating(eg) additional insulation not the whole costof the work
b the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to the BCB andbe confirmed in a report signed by a suitablyqualified person
c the annual energy savings should beestimated using SAP 20091
d for the purposes of this Approved Documentthe energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings Current energy prices can be obtainedfrom the DECC website2
Thermal element is defined in regulation 2(3)of the Building Regulations as follows
2(3) In these Regulations lsquothermal elementrsquomeans a wall floor or roof (but does not includewindows doors roof windows or roof-lights)which separates a thermally conditioned part ofthe building (lsquothe conditioned spacersquo) from
a the external environment (including theground) or
b in the case of floors and walls another part ofthe building which is
i unconditioned
1 wwwbrecouksap20092 wwwdeccgovukencontentcmsstatisticspublicationpricespricesaspx
Section 3 General guidance
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Conservation of fuel and power Approved Document L1B
L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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GENERAL GUIDANCE L1B
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Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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L1B GENERAL GUIDANCE
10
Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
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Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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Approved Document L1B Conservation of fuel and power
GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Conservation of fuel and power Approved Document L1B
Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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GUIDANCE RELATING TO BUILDING WORK L1B
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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MAIN CHANGES IN THE
2010 EDITION1 This Approved Document L1B came into force
on 1 October 2010 in support of the Buildingand Approved Inspectors (Amendment)Regulations 2010 SI 2010 No 719 The mainchanges to the legal requirements and the
supporting guidance in this edition of Approved Document L1B are as follows
Changes in the legal requirements
2 The exemption from the energy efficiencyprovisions for extensions consisting of aconservatory or porch is amended to grantthe exemption only where any existing wallswindows or doors are retained or replaced ifremoved and where the heating system ofthe building is not extended into theconservatory or porch
3 The list of work in Schedule 4 (work thatneed not be notified to building control) isamended to include the installation ofthermal insulation in a roof space or loftspace where this is the only work carried outand the work is not carried out to complywith any requirement in the BuildingRegulations
Changes in the technical guidance
4 In this Approved Document the guidance isgenerally based upon an elemental approachto demonstrating compliance with additionalguidance that provides greater flexibility Themain technical changes comprise a generalstrengthening of energy efficiency standardsthat are considered reasonable for work onthermal elements controlled fittings andcontrolled services in existing dwellings
5 Amended guidance is given for historic andtraditional buildings which may have anexemption from the energy efficiencyrequirements or where special considerationsapply
6 Amended guidance is given where anextension is a conservatory or porch that isnot exempt from the energy efficiencyrequirements
7 The guidance for the renovation of a thermalelement through the provision of a new layeror through the replacement of an existinglayer has been expanded
8 Guidance is provided for swimming poolbasins (walls and floor) in existing dwellings
Main changes made by the
2010 and 2011 amendmentsThis 2010 edition incorporating the further2010 amendments reflects the changes madeas a result of the Building Regulations 2010Building Approved inspector etc Regulationsand the Building (Amendment) Regulations
2011 The changes mainly reflect regulationnumber changes as a result of re-ordering Therehave been no amendments to the substantiverequirements in Schedule 1(ie Parts A to P) ofthe Building Regulations
Please note the simplification of the definitionof lsquoroom for residential purposesrsquo in regulation2 of the Building Regulations 2010 and theamendment of the definition of ldquorenovationrdquoin regulation 2(1) of the Building (Amendment)Regulations 2011 Please also note that L1(c) hasnow become regulation 40
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Approved Document L1B Conservation of fuel and power
PAGE
Section 1 Introduction 2
What is an Approved Document 2
Consideration of technical risk 2
How to use this Approved Document 2
Where you can get further help 3
Responsibility for compliance 3
Section 2 The requirements 4
LIMITATION ON REQUIREMENTS 6
Section 3 General guidance 7
Key terms 7
Types of work covered by this
Approved Document 8Dwellings within the scope of theenergy efficiency requirements 8
Dwellings exempt from the energyefficiency requirements 8
Notification of work covered by theenergy efficiency requirements 9
Materials and workmanship 10
The Workplace (Health Safety andWelfare) Regulations 1992 11
Section 4 Guidance relating tobuilding work 12
THE EXTENSION OF A DWELLING 12
Reference method 12
Optional approaches with moredesign flexibility 12
Conservatories and porches 12
Swimming pool basins 13
MATERIAL CHANGE OF USE ANDCHANGE OF ENERGY STATUS 13
Material change of use 13
Change of energy status 13
Option providing more design flexibility 14
WORK ON CONTROLLED FITTINGS AND SERVICES 14
Controlled fittings 14
Controlled services 15
COMMISSIONING OF FIXED BUILDINGSERVICES 15
PAGE
Section 5 Guidance on thermal elements 17
THE PROVISION OF THERMAL ELEMENTS 17
U-values 17
Continuity of insulation and airtightness 17
RENOVATION OF THERMAL ELEMENTS 17
RETAINED THERMAL ELEMENTS 18
Section 6 Consequential improvements toenergy performance 19
Section 7 Providing information 20
Appendix A Work to thermal elements 21
Appendix B Documents referred to 24
Appendix C Standards referred to 25
Index 26
Contents L1BN L I N E V E R I N
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L1B
Conservation of fuel and power Approved Document L1B
2
Section 1 Introduction
What is an Approved Document
11 This Approved Document which takeseffect on 1 October 2010 has been approvedand issued by the Secretary of State to providepractical guidance on ways of complying with the
energy efficiency requirements (see Section 2)and regulation 7 of the Building Regulations 2010(SI 20102214) for England and Wales Regulation2(1) of the Building Regulations defines theenergy efficiency requirements as therequirements of regulations 23 26 28 29 40and Part L of Schedule 1 The BuildingRegulations 2010 are referred to throughout theremainder of this Document as lsquothe BuildingRegulationsrsquo
12 The intention of issuing Approved Documentsis to provide guidance about compliance withspecific aspects of building regulations in some
of the more common building situations Theyset out what in ordinary circumstances may beaccepted as reasonable provision for compliancewith the relevant requirement(s) of buildingregulations to which they refer
13 If guidance in an Approved Documentis followed there will be a presumption ofcompliance with the requirement(s) covered bythe guidance However this presumption can beoverturned so simply following guidance doesnot guarantee compliance for example if theparticular case is unusual in some way thenlsquonormalrsquo guidance may not be applicable It is
also important to note that there may well beother ways of achieving compliance with therequirements There is therefore no obligationto adopt any particular solution contained inthis Approved Document if you would preferto meet the relevant requirement in someother way Persons intending to carry outbuilding work should always check with theirbuilding control body either the local authorityor an approved inspector that their proposalscomply with building regulations
14 It is important to note that this ApprovedDocument as well as containing guidance also
contains extracts from the Regulations Suchregulatory text must be complied with as statedFor example the requirement that fixed building services must be commissioned (regulation 44)is a regulatory requirement There is therefore noflexibility to ignore this requirement neither cancompliance with this particular regulation bedemonstrated via any route other than that setout in regulation 44
15 The guidance contained in this ApprovedDocument relates only to the particularrequirements of the Building Regulations that thedocument addresses (set out in Section 2)
However building work may be subject to morethan one requirement of building regulations Insuch cases the work will also have to comply
with any other applicable requirements ofbuilding regulations
16 There are Approved Documents that giveguidance on each of the Parts of Schedule 1 andon regulation 7 A full list of these is provided at
the back of this document
Consideration of technical risk
17 Building work to existing dwellings mustsatisfy all the technical requirements set outin regulations 23 22 28 and 29 of and Schedule1 to the Building Regulations When consideringthe incorporation of energy efficiency measuresin dwellings attention should alsobe paid in particular to the need to comply withPart B (fire safety) Part C (site preparation andresistance to contaminants and moisture) Part E(resistance to the passage of sound) Part F
(ventilation) paragraph G3 (hot water supply andsystems) Part J (combustion appliances and fuelstorage systems) and Part P (electrical safety)of Schedule 1 to the Building Regulations aswell as Part L The adoption of any particularenergy efficiency measure should not involveunacceptable technical risk of for instanceexcessive condensation Designers and buildersshould refer to the relevant Approved Documentsand to other generally available good practiceguidance to help minimise these risks
How to use this Approved Document
18 This Approved Document is subdividedinto seven sections as detailed below Thesesections are followed by supporting appendices
This introductory section sets out the generalcontext in which the guidance in this ApprovedDocument must be considered
Section 2 sets out the relevant legal requirementscontained in the Building Regulations
Section 3 contains general guidance includingthe definition of key terms the types of buildingwork covered by this Approved Documentthe types of building work that are exempt
procedures for notifying work materials andworkmanship and health and safety issues
Section 4 gives guidance on reasonableprovision for various types of building work
Section 5 deals with the particular case of workto thermal elements
Section 6 gives guidance in support of therequirement for consequential improvements for buildings over 1000 m2
Section 7 describes the information that shouldbe provided to occupiers to help them achievereasonable standards of energy efficiency inpractice
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Approved Document L1B Conservation of fuel and power
INTRODUCTION L1B
19 In this document the following conventionshave been adopted to assist understanding andinterpretation
a Texts shown against a green background areextracts from the Building Regulations 2010(SI 20102214) or Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)and set out the legal requirements that relateto compliance with the energy efficiency requirements of building regulations As statedpreviously there is no flexibility in respect ofsuch text it defines a legal requirement notguidance for typical situations It should alsobe remembered that as noted abovebuilding works must comply with all the otherapplicable requirements of building regulations
b Key terms are defined in paragraph 31 andare printed in bold italic text
c Details of technical publications referred toin the text of this Approved Document will be
given in footnotes and repeated as referencesat the end of the document A reference to apublication is likely to be made for one of twomain reasons The publication may containadditional or more comprehensive technicaldetail which it would be impractical toinclude in full in the Approved Document butwhich is needed to fully explain ways ofmeeting the requirements or it is a source ofmore general information The reason for thereference will be indicated in each case Thereference will be to a specified edition of thedocument The Approved Document may beamended from time to time to include newreferences or to refer to revised editionswhere this aids compliance
d Additional commentary in italic text appearsafter some numbered paragraphs Thiscommentary is intended to assist understandingof the immediately preceding paragraph orsub-paragraph or to direct readers tosources of additional information but is notpart of the technical guidance itself
Where you can get further help
110 If you do not understand the technical
guidance or other information set out in this Approved Document and the additional detailedtechnical references to which it directs you thereare a number of routes through which you canseek further assistance
bull the Department for Communities andLocal Government websitewwwcommunitiesgovuk
bull the Planning Portal websitewwwplanningportalgovuk
bull if you are the person undertaking the buildingwork you can seek assistance either from
your local authority building control service orfrom your approved inspector (depending onwhich building control service you are using
bull persons registered with a competent personself-certification scheme may be able to gettechnical advice from their scheme operator
bull if your query is of a highly technical natureyou may wish to seek the advice of aspecialist or industry technical body forthe relevant subject
Responsibility for compliance111 It is important to remember that if youare the person (eg designer builder installer)carrying out building work to which anyrequirement of building regulations applies youhave a responsibility to ensure that the workcomplies with any such requirement The buildingowner may also have a responsibility for ensuringcompliance with building regulation requirementsand could be served with an enforcement noticein cases of non-compliance
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Conservation of fuel and power Approved Document L1B
L1B
21 This Approved Document which takeseffect on 1 October 2010 deals with the energyefficiency requirements in the BuildingRegulations Regulation 2(1) of the BuildingRegulations defines the energy efficiency requirements as the requirements of regulations23 26 28 40 and Part L of Schedule 1 Theenergy efficiency requirements relevantto existing dwellings are in regulations 23 28 29and 40 of and Part L of Schedule 1 to thoseRegulations as set out below
Requirements relating to thermal elements ndash Regulation 23
(1) Where a person intends to renovate a thermal element
such work shall be carried out as is necessary to ensure that the
whole thermal element complies with the requirements of
paragraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the new thermal
element shall comply with the requirements of paragraph L1(a)
(i) of Schedule 1
Consequential improvements to energy performance
Regulation 28
(1) Paragraph (2) applies to an existing building with a total
useful floor area over 1000 m2 where the proposed building
work consists of or includesmdash
(a) an extension
(b) the initial provision of any fixed building services or
(c) an increase to the installed capacity of any fixed
building services
(2) Subject to paragraph (3) where this paragraph applies
such work if any shall be carried out as is necessary to ensure
that the building complies with the requirements of Part L of
Schedule 1
(3) Nothing in paragraph (2) requires work to be carried out if
it is not technically functionally or economically feasible
Energy performance certificates ndash Regulation 29
(1) This regulation applies wheremdash
(a) a building is erected or
(b) a building is modified so that it has a greater or fewer
number of parts designed or altered for separate use than it
previously had where the modif ication includes the provision
or extension of any of the fixed services for heating hot water
air conditioning or mechanical ventilation
(2) The person carrying out the work shallmdash
(a) give an energy performance certificate for the building
to the owner of the building and
(b) give to the local authority notice to that effect
including the reference number under which the energy
performance certificate has been registered in accordance withregulation 17F(4)
Section 2 The requirements
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Approved Document L1B Conservation of fuel and power
THE REQUIREMENTS L1B
Energy performance certificates ndash Regulation 29 (continued)
(3) The energy performance certificate and notice shall be
given not later than f ive days after the work has been completed
(4) An energy performance certificate mustmdash
(a) express the asset rating of the building in a way
approved by the Secretary of State under regulation 24
(b) include a reference value such as a current legal
standard or benchmark
(c) be issued by an energy assessor who is accredited to
produce energy performance certificates for that category of
building and
(d) include the following informationmdash
(i) the reference number under which the certificate
has been registered in accordance with regulation 30(4)
(ii) the address of the building
(iii) an estimate of the total useful floor area of the
building
(iv) the name of the energy assessor who issued it
(v) the name and address of the energy assessorrsquos
employer or if he is self-employed the name under which he
trades and his address
(vi) the date on which it was issued and
(vii) the name of the approved accreditation scheme of
which the energy assessor is a member
(5) The energy performance certificate must be accompanied
by a recommendation report containing recommendations for
the improvement of the energy performance of the building
issued by the energy assessor who issued the energy
performance certificate
(6) Certification for apartments or units designed or alteredfor separate use in blocks may be basedmdash
(a) except in the case of a dwelling on a common
certification of the whole building for blocks with a common
heating system or
(b) on the assessment of another representative apartment
or unit in the same block
(7) Wheremdash
(a) a block with a common heating system is divided into
parts designed or altered for separate use and
(b) one or more but not all of the parts are dwellings
certification for those parts which are not dwellings may be based on a common certification of all the parts which are not
dwellings
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L1B THE REQUIREMENTS
6
Conservation of fuel and power Approved Document L1B
Requirement Limits on application
Schedule 1 ndash Part L Conservation of fuel and power
L1 Reasonable provision shall be made for the conservation of
fuel and power in buildings by
(a) limiting heat gains and lossesmdash
(i) through thermal elements and other parts of the
building fabric and
(ii) from pipes ducts and vessels used for space
heating space cooling and hot water services
(b) providing fixed building services whichmdash
(i) are energy efficient
(ii) have effective controls and
(iii) are commissioned by testing and adjusting as
necessary to ensure they use no more fuel and power than is
reasonable in the circumstances and
Regulation 40 providing to the owner sufficient informationabout the building the fixed building services and their
maintenance requirements so that the building can be operated
in such a manner as to use no more fuel and power than is
reasonable in the circumstances
LIMITATION ON REQUIREMENTS
22 In accordance with regulation 8 of theBuilding Regulations the requirements in Parts Ato D F to K and N (except for paragraphs G2 H2and J7) of Schedule 1 to the Building Regulations
do not require anything to be done except for thepurpose of securing reasonable standards ofhealth and safety for persons in or about buildings(and any others who may be affected by buildingsor matters connected with buildings)
23 Paragraph G2 is excluded as it deals withwater efficiency and paragraphs H2 and J7 areexcluded from regulation 8 because they dealdirectly with prevention of the contamination ofwater Parts E and M (which deal respectivelywith resistance to the passage of sound andaccess to and use of buildings) are excludedfrom regulation 8 because they address the
welfare and convenience of building users Part Lis excluded from regulation 8 because it addressesthe conservation of fuel and power
24 In addition regulation 4(2) of the BuildingRegulations states that where the work is beingcarried out in order to comply with regulation 23(requirements relating to renovation or replacementof a thermal element ) regulation 22 (requirementsrelating to a change of a buildingrsquos energy status)or regulation 28 ( consequential improvements to energy performance) and is not a materialalteration it need comply only with the requirementsof Part L
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Approved Document L1B Conservation of fuel and power
L1B
Key terms
31 The following are key terms used in thisdocument
BCB means Building Control Body a local
authority or an approved inspectorCommissioning means the advancement ofa fixed building service following installationreplacement or alteration of the whole or partof the system from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances without prejudice to the needto comply with health and safety requirementsFor each system commissioning includessetting-to-work regulation (that is testing andadjusting repetitively) to achieve the specified
performance the calibration setting up andtesting of the associated automatic controlsystems and recording of the system settingsand the performance test results that have beenaccepted as satisfactory
Consequential improvements means thoseenergy efficiency improvements required byregulation 28
Controlled service or fitting means a service orfitting in relation to which Part G (sanitation hotwater safety and water efficiency) H (drainageand waste disposal) J (combustion appliancesand fuel storage systems) L (conservation of fuel
and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement
Dwelling means a self-contained unit includinga house or a flat designed to be used separatelyto accommodate a single household ( Rooms for residential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings)
Energy efficiency requirements means therequirements of regulations 23 26 28 29 and40 of and Part L of Schedule 1 to the BuildingRegulations
In respect of existing dwellings the applicable requirements consist of Part L and regulations 23 38 and 40
Fixed building services means any part of orany controls associated with
a fixed internal or external lighting systems butdoes not include emergency escape lightingor specialist process lighting or
b fixed systems for heating hot water airconditioning or mechanical ventilation
Room for residential purposes means a room ora suite of rooms which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel anhotel a boarding house a hall of residence or a
residential home but does not include a room in ahospital or other similar establishment used forpatient accommodation
lsquo Renovationrsquo in relation to a thermal elementmeans the provision of a new layer in the thermalelement (other than where that new layer isprovided solely as a means of repair to a flatroof) or the replacement of an existing layer butexcludes decorative finishes and lsquorenovatersquo shallbe construed accordingly
Simple payback means the amount of time itwill take to recover the initial investment through
energy savings and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT When making thiscalculation the following guidance should be used
a the marginal additional cost is the additionalcost (materials and labour) of incorporating(eg) additional insulation not the whole costof the work
b the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to the BCB andbe confirmed in a report signed by a suitablyqualified person
c the annual energy savings should beestimated using SAP 20091
d for the purposes of this Approved Documentthe energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings Current energy prices can be obtainedfrom the DECC website2
Thermal element is defined in regulation 2(3)of the Building Regulations as follows
2(3) In these Regulations lsquothermal elementrsquomeans a wall floor or roof (but does not includewindows doors roof windows or roof-lights)which separates a thermally conditioned part ofthe building (lsquothe conditioned spacersquo) from
a the external environment (including theground) or
b in the case of floors and walls another part ofthe building which is
i unconditioned
1 wwwbrecouksap20092 wwwdeccgovukencontentcmsstatisticspublicationpricespricesaspx
Section 3 General guidance
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L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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GENERAL GUIDANCE L1B
9
Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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L1B GENERAL GUIDANCE
10
Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
11
Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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Conservation of fuel and power Approved Document L1B
L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Approved Document L1B Conservation of fuel and power
PAGE
Section 1 Introduction 2
What is an Approved Document 2
Consideration of technical risk 2
How to use this Approved Document 2
Where you can get further help 3
Responsibility for compliance 3
Section 2 The requirements 4
LIMITATION ON REQUIREMENTS 6
Section 3 General guidance 7
Key terms 7
Types of work covered by this
Approved Document 8Dwellings within the scope of theenergy efficiency requirements 8
Dwellings exempt from the energyefficiency requirements 8
Notification of work covered by theenergy efficiency requirements 9
Materials and workmanship 10
The Workplace (Health Safety andWelfare) Regulations 1992 11
Section 4 Guidance relating tobuilding work 12
THE EXTENSION OF A DWELLING 12
Reference method 12
Optional approaches with moredesign flexibility 12
Conservatories and porches 12
Swimming pool basins 13
MATERIAL CHANGE OF USE ANDCHANGE OF ENERGY STATUS 13
Material change of use 13
Change of energy status 13
Option providing more design flexibility 14
WORK ON CONTROLLED FITTINGS AND SERVICES 14
Controlled fittings 14
Controlled services 15
COMMISSIONING OF FIXED BUILDINGSERVICES 15
PAGE
Section 5 Guidance on thermal elements 17
THE PROVISION OF THERMAL ELEMENTS 17
U-values 17
Continuity of insulation and airtightness 17
RENOVATION OF THERMAL ELEMENTS 17
RETAINED THERMAL ELEMENTS 18
Section 6 Consequential improvements toenergy performance 19
Section 7 Providing information 20
Appendix A Work to thermal elements 21
Appendix B Documents referred to 24
Appendix C Standards referred to 25
Index 26
Contents L1BN L I N E V E R I N
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L1B
Conservation of fuel and power Approved Document L1B
2
Section 1 Introduction
What is an Approved Document
11 This Approved Document which takeseffect on 1 October 2010 has been approvedand issued by the Secretary of State to providepractical guidance on ways of complying with the
energy efficiency requirements (see Section 2)and regulation 7 of the Building Regulations 2010(SI 20102214) for England and Wales Regulation2(1) of the Building Regulations defines theenergy efficiency requirements as therequirements of regulations 23 26 28 29 40and Part L of Schedule 1 The BuildingRegulations 2010 are referred to throughout theremainder of this Document as lsquothe BuildingRegulationsrsquo
12 The intention of issuing Approved Documentsis to provide guidance about compliance withspecific aspects of building regulations in some
of the more common building situations Theyset out what in ordinary circumstances may beaccepted as reasonable provision for compliancewith the relevant requirement(s) of buildingregulations to which they refer
13 If guidance in an Approved Documentis followed there will be a presumption ofcompliance with the requirement(s) covered bythe guidance However this presumption can beoverturned so simply following guidance doesnot guarantee compliance for example if theparticular case is unusual in some way thenlsquonormalrsquo guidance may not be applicable It is
also important to note that there may well beother ways of achieving compliance with therequirements There is therefore no obligationto adopt any particular solution contained inthis Approved Document if you would preferto meet the relevant requirement in someother way Persons intending to carry outbuilding work should always check with theirbuilding control body either the local authorityor an approved inspector that their proposalscomply with building regulations
14 It is important to note that this ApprovedDocument as well as containing guidance also
contains extracts from the Regulations Suchregulatory text must be complied with as statedFor example the requirement that fixed building services must be commissioned (regulation 44)is a regulatory requirement There is therefore noflexibility to ignore this requirement neither cancompliance with this particular regulation bedemonstrated via any route other than that setout in regulation 44
15 The guidance contained in this ApprovedDocument relates only to the particularrequirements of the Building Regulations that thedocument addresses (set out in Section 2)
However building work may be subject to morethan one requirement of building regulations Insuch cases the work will also have to comply
with any other applicable requirements ofbuilding regulations
16 There are Approved Documents that giveguidance on each of the Parts of Schedule 1 andon regulation 7 A full list of these is provided at
the back of this document
Consideration of technical risk
17 Building work to existing dwellings mustsatisfy all the technical requirements set outin regulations 23 22 28 and 29 of and Schedule1 to the Building Regulations When consideringthe incorporation of energy efficiency measuresin dwellings attention should alsobe paid in particular to the need to comply withPart B (fire safety) Part C (site preparation andresistance to contaminants and moisture) Part E(resistance to the passage of sound) Part F
(ventilation) paragraph G3 (hot water supply andsystems) Part J (combustion appliances and fuelstorage systems) and Part P (electrical safety)of Schedule 1 to the Building Regulations aswell as Part L The adoption of any particularenergy efficiency measure should not involveunacceptable technical risk of for instanceexcessive condensation Designers and buildersshould refer to the relevant Approved Documentsand to other generally available good practiceguidance to help minimise these risks
How to use this Approved Document
18 This Approved Document is subdividedinto seven sections as detailed below Thesesections are followed by supporting appendices
This introductory section sets out the generalcontext in which the guidance in this ApprovedDocument must be considered
Section 2 sets out the relevant legal requirementscontained in the Building Regulations
Section 3 contains general guidance includingthe definition of key terms the types of buildingwork covered by this Approved Documentthe types of building work that are exempt
procedures for notifying work materials andworkmanship and health and safety issues
Section 4 gives guidance on reasonableprovision for various types of building work
Section 5 deals with the particular case of workto thermal elements
Section 6 gives guidance in support of therequirement for consequential improvements for buildings over 1000 m2
Section 7 describes the information that shouldbe provided to occupiers to help them achievereasonable standards of energy efficiency inpractice
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Approved Document L1B Conservation of fuel and power
INTRODUCTION L1B
19 In this document the following conventionshave been adopted to assist understanding andinterpretation
a Texts shown against a green background areextracts from the Building Regulations 2010(SI 20102214) or Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)and set out the legal requirements that relateto compliance with the energy efficiency requirements of building regulations As statedpreviously there is no flexibility in respect ofsuch text it defines a legal requirement notguidance for typical situations It should alsobe remembered that as noted abovebuilding works must comply with all the otherapplicable requirements of building regulations
b Key terms are defined in paragraph 31 andare printed in bold italic text
c Details of technical publications referred toin the text of this Approved Document will be
given in footnotes and repeated as referencesat the end of the document A reference to apublication is likely to be made for one of twomain reasons The publication may containadditional or more comprehensive technicaldetail which it would be impractical toinclude in full in the Approved Document butwhich is needed to fully explain ways ofmeeting the requirements or it is a source ofmore general information The reason for thereference will be indicated in each case Thereference will be to a specified edition of thedocument The Approved Document may beamended from time to time to include newreferences or to refer to revised editionswhere this aids compliance
d Additional commentary in italic text appearsafter some numbered paragraphs Thiscommentary is intended to assist understandingof the immediately preceding paragraph orsub-paragraph or to direct readers tosources of additional information but is notpart of the technical guidance itself
Where you can get further help
110 If you do not understand the technical
guidance or other information set out in this Approved Document and the additional detailedtechnical references to which it directs you thereare a number of routes through which you canseek further assistance
bull the Department for Communities andLocal Government websitewwwcommunitiesgovuk
bull the Planning Portal websitewwwplanningportalgovuk
bull if you are the person undertaking the buildingwork you can seek assistance either from
your local authority building control service orfrom your approved inspector (depending onwhich building control service you are using
bull persons registered with a competent personself-certification scheme may be able to gettechnical advice from their scheme operator
bull if your query is of a highly technical natureyou may wish to seek the advice of aspecialist or industry technical body forthe relevant subject
Responsibility for compliance111 It is important to remember that if youare the person (eg designer builder installer)carrying out building work to which anyrequirement of building regulations applies youhave a responsibility to ensure that the workcomplies with any such requirement The buildingowner may also have a responsibility for ensuringcompliance with building regulation requirementsand could be served with an enforcement noticein cases of non-compliance
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Conservation of fuel and power Approved Document L1B
L1B
21 This Approved Document which takeseffect on 1 October 2010 deals with the energyefficiency requirements in the BuildingRegulations Regulation 2(1) of the BuildingRegulations defines the energy efficiency requirements as the requirements of regulations23 26 28 40 and Part L of Schedule 1 Theenergy efficiency requirements relevantto existing dwellings are in regulations 23 28 29and 40 of and Part L of Schedule 1 to thoseRegulations as set out below
Requirements relating to thermal elements ndash Regulation 23
(1) Where a person intends to renovate a thermal element
such work shall be carried out as is necessary to ensure that the
whole thermal element complies with the requirements of
paragraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the new thermal
element shall comply with the requirements of paragraph L1(a)
(i) of Schedule 1
Consequential improvements to energy performance
Regulation 28
(1) Paragraph (2) applies to an existing building with a total
useful floor area over 1000 m2 where the proposed building
work consists of or includesmdash
(a) an extension
(b) the initial provision of any fixed building services or
(c) an increase to the installed capacity of any fixed
building services
(2) Subject to paragraph (3) where this paragraph applies
such work if any shall be carried out as is necessary to ensure
that the building complies with the requirements of Part L of
Schedule 1
(3) Nothing in paragraph (2) requires work to be carried out if
it is not technically functionally or economically feasible
Energy performance certificates ndash Regulation 29
(1) This regulation applies wheremdash
(a) a building is erected or
(b) a building is modified so that it has a greater or fewer
number of parts designed or altered for separate use than it
previously had where the modif ication includes the provision
or extension of any of the fixed services for heating hot water
air conditioning or mechanical ventilation
(2) The person carrying out the work shallmdash
(a) give an energy performance certificate for the building
to the owner of the building and
(b) give to the local authority notice to that effect
including the reference number under which the energy
performance certificate has been registered in accordance withregulation 17F(4)
Section 2 The requirements
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Approved Document L1B Conservation of fuel and power
THE REQUIREMENTS L1B
Energy performance certificates ndash Regulation 29 (continued)
(3) The energy performance certificate and notice shall be
given not later than f ive days after the work has been completed
(4) An energy performance certificate mustmdash
(a) express the asset rating of the building in a way
approved by the Secretary of State under regulation 24
(b) include a reference value such as a current legal
standard or benchmark
(c) be issued by an energy assessor who is accredited to
produce energy performance certificates for that category of
building and
(d) include the following informationmdash
(i) the reference number under which the certificate
has been registered in accordance with regulation 30(4)
(ii) the address of the building
(iii) an estimate of the total useful floor area of the
building
(iv) the name of the energy assessor who issued it
(v) the name and address of the energy assessorrsquos
employer or if he is self-employed the name under which he
trades and his address
(vi) the date on which it was issued and
(vii) the name of the approved accreditation scheme of
which the energy assessor is a member
(5) The energy performance certificate must be accompanied
by a recommendation report containing recommendations for
the improvement of the energy performance of the building
issued by the energy assessor who issued the energy
performance certificate
(6) Certification for apartments or units designed or alteredfor separate use in blocks may be basedmdash
(a) except in the case of a dwelling on a common
certification of the whole building for blocks with a common
heating system or
(b) on the assessment of another representative apartment
or unit in the same block
(7) Wheremdash
(a) a block with a common heating system is divided into
parts designed or altered for separate use and
(b) one or more but not all of the parts are dwellings
certification for those parts which are not dwellings may be based on a common certification of all the parts which are not
dwellings
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L1B THE REQUIREMENTS
6
Conservation of fuel and power Approved Document L1B
Requirement Limits on application
Schedule 1 ndash Part L Conservation of fuel and power
L1 Reasonable provision shall be made for the conservation of
fuel and power in buildings by
(a) limiting heat gains and lossesmdash
(i) through thermal elements and other parts of the
building fabric and
(ii) from pipes ducts and vessels used for space
heating space cooling and hot water services
(b) providing fixed building services whichmdash
(i) are energy efficient
(ii) have effective controls and
(iii) are commissioned by testing and adjusting as
necessary to ensure they use no more fuel and power than is
reasonable in the circumstances and
Regulation 40 providing to the owner sufficient informationabout the building the fixed building services and their
maintenance requirements so that the building can be operated
in such a manner as to use no more fuel and power than is
reasonable in the circumstances
LIMITATION ON REQUIREMENTS
22 In accordance with regulation 8 of theBuilding Regulations the requirements in Parts Ato D F to K and N (except for paragraphs G2 H2and J7) of Schedule 1 to the Building Regulations
do not require anything to be done except for thepurpose of securing reasonable standards ofhealth and safety for persons in or about buildings(and any others who may be affected by buildingsor matters connected with buildings)
23 Paragraph G2 is excluded as it deals withwater efficiency and paragraphs H2 and J7 areexcluded from regulation 8 because they dealdirectly with prevention of the contamination ofwater Parts E and M (which deal respectivelywith resistance to the passage of sound andaccess to and use of buildings) are excludedfrom regulation 8 because they address the
welfare and convenience of building users Part Lis excluded from regulation 8 because it addressesthe conservation of fuel and power
24 In addition regulation 4(2) of the BuildingRegulations states that where the work is beingcarried out in order to comply with regulation 23(requirements relating to renovation or replacementof a thermal element ) regulation 22 (requirementsrelating to a change of a buildingrsquos energy status)or regulation 28 ( consequential improvements to energy performance) and is not a materialalteration it need comply only with the requirementsof Part L
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L1B
Key terms
31 The following are key terms used in thisdocument
BCB means Building Control Body a local
authority or an approved inspectorCommissioning means the advancement ofa fixed building service following installationreplacement or alteration of the whole or partof the system from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances without prejudice to the needto comply with health and safety requirementsFor each system commissioning includessetting-to-work regulation (that is testing andadjusting repetitively) to achieve the specified
performance the calibration setting up andtesting of the associated automatic controlsystems and recording of the system settingsand the performance test results that have beenaccepted as satisfactory
Consequential improvements means thoseenergy efficiency improvements required byregulation 28
Controlled service or fitting means a service orfitting in relation to which Part G (sanitation hotwater safety and water efficiency) H (drainageand waste disposal) J (combustion appliancesand fuel storage systems) L (conservation of fuel
and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement
Dwelling means a self-contained unit includinga house or a flat designed to be used separatelyto accommodate a single household ( Rooms for residential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings)
Energy efficiency requirements means therequirements of regulations 23 26 28 29 and40 of and Part L of Schedule 1 to the BuildingRegulations
In respect of existing dwellings the applicable requirements consist of Part L and regulations 23 38 and 40
Fixed building services means any part of orany controls associated with
a fixed internal or external lighting systems butdoes not include emergency escape lightingor specialist process lighting or
b fixed systems for heating hot water airconditioning or mechanical ventilation
Room for residential purposes means a room ora suite of rooms which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel anhotel a boarding house a hall of residence or a
residential home but does not include a room in ahospital or other similar establishment used forpatient accommodation
lsquo Renovationrsquo in relation to a thermal elementmeans the provision of a new layer in the thermalelement (other than where that new layer isprovided solely as a means of repair to a flatroof) or the replacement of an existing layer butexcludes decorative finishes and lsquorenovatersquo shallbe construed accordingly
Simple payback means the amount of time itwill take to recover the initial investment through
energy savings and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT When making thiscalculation the following guidance should be used
a the marginal additional cost is the additionalcost (materials and labour) of incorporating(eg) additional insulation not the whole costof the work
b the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to the BCB andbe confirmed in a report signed by a suitablyqualified person
c the annual energy savings should beestimated using SAP 20091
d for the purposes of this Approved Documentthe energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings Current energy prices can be obtainedfrom the DECC website2
Thermal element is defined in regulation 2(3)of the Building Regulations as follows
2(3) In these Regulations lsquothermal elementrsquomeans a wall floor or roof (but does not includewindows doors roof windows or roof-lights)which separates a thermally conditioned part ofthe building (lsquothe conditioned spacersquo) from
a the external environment (including theground) or
b in the case of floors and walls another part ofthe building which is
i unconditioned
1 wwwbrecouksap20092 wwwdeccgovukencontentcmsstatisticspublicationpricespricesaspx
Section 3 General guidance
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L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
11
Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Conservation of fuel and power Approved Document L1B
Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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Published by NBS part of RIBA Enterprises Ltd and available from
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15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
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RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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L1B
Conservation of fuel and power Approved Document L1B
2
Section 1 Introduction
What is an Approved Document
11 This Approved Document which takeseffect on 1 October 2010 has been approvedand issued by the Secretary of State to providepractical guidance on ways of complying with the
energy efficiency requirements (see Section 2)and regulation 7 of the Building Regulations 2010(SI 20102214) for England and Wales Regulation2(1) of the Building Regulations defines theenergy efficiency requirements as therequirements of regulations 23 26 28 29 40and Part L of Schedule 1 The BuildingRegulations 2010 are referred to throughout theremainder of this Document as lsquothe BuildingRegulationsrsquo
12 The intention of issuing Approved Documentsis to provide guidance about compliance withspecific aspects of building regulations in some
of the more common building situations Theyset out what in ordinary circumstances may beaccepted as reasonable provision for compliancewith the relevant requirement(s) of buildingregulations to which they refer
13 If guidance in an Approved Documentis followed there will be a presumption ofcompliance with the requirement(s) covered bythe guidance However this presumption can beoverturned so simply following guidance doesnot guarantee compliance for example if theparticular case is unusual in some way thenlsquonormalrsquo guidance may not be applicable It is
also important to note that there may well beother ways of achieving compliance with therequirements There is therefore no obligationto adopt any particular solution contained inthis Approved Document if you would preferto meet the relevant requirement in someother way Persons intending to carry outbuilding work should always check with theirbuilding control body either the local authorityor an approved inspector that their proposalscomply with building regulations
14 It is important to note that this ApprovedDocument as well as containing guidance also
contains extracts from the Regulations Suchregulatory text must be complied with as statedFor example the requirement that fixed building services must be commissioned (regulation 44)is a regulatory requirement There is therefore noflexibility to ignore this requirement neither cancompliance with this particular regulation bedemonstrated via any route other than that setout in regulation 44
15 The guidance contained in this ApprovedDocument relates only to the particularrequirements of the Building Regulations that thedocument addresses (set out in Section 2)
However building work may be subject to morethan one requirement of building regulations Insuch cases the work will also have to comply
with any other applicable requirements ofbuilding regulations
16 There are Approved Documents that giveguidance on each of the Parts of Schedule 1 andon regulation 7 A full list of these is provided at
the back of this document
Consideration of technical risk
17 Building work to existing dwellings mustsatisfy all the technical requirements set outin regulations 23 22 28 and 29 of and Schedule1 to the Building Regulations When consideringthe incorporation of energy efficiency measuresin dwellings attention should alsobe paid in particular to the need to comply withPart B (fire safety) Part C (site preparation andresistance to contaminants and moisture) Part E(resistance to the passage of sound) Part F
(ventilation) paragraph G3 (hot water supply andsystems) Part J (combustion appliances and fuelstorage systems) and Part P (electrical safety)of Schedule 1 to the Building Regulations aswell as Part L The adoption of any particularenergy efficiency measure should not involveunacceptable technical risk of for instanceexcessive condensation Designers and buildersshould refer to the relevant Approved Documentsand to other generally available good practiceguidance to help minimise these risks
How to use this Approved Document
18 This Approved Document is subdividedinto seven sections as detailed below Thesesections are followed by supporting appendices
This introductory section sets out the generalcontext in which the guidance in this ApprovedDocument must be considered
Section 2 sets out the relevant legal requirementscontained in the Building Regulations
Section 3 contains general guidance includingthe definition of key terms the types of buildingwork covered by this Approved Documentthe types of building work that are exempt
procedures for notifying work materials andworkmanship and health and safety issues
Section 4 gives guidance on reasonableprovision for various types of building work
Section 5 deals with the particular case of workto thermal elements
Section 6 gives guidance in support of therequirement for consequential improvements for buildings over 1000 m2
Section 7 describes the information that shouldbe provided to occupiers to help them achievereasonable standards of energy efficiency inpractice
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Approved Document L1B Conservation of fuel and power
INTRODUCTION L1B
19 In this document the following conventionshave been adopted to assist understanding andinterpretation
a Texts shown against a green background areextracts from the Building Regulations 2010(SI 20102214) or Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)and set out the legal requirements that relateto compliance with the energy efficiency requirements of building regulations As statedpreviously there is no flexibility in respect ofsuch text it defines a legal requirement notguidance for typical situations It should alsobe remembered that as noted abovebuilding works must comply with all the otherapplicable requirements of building regulations
b Key terms are defined in paragraph 31 andare printed in bold italic text
c Details of technical publications referred toin the text of this Approved Document will be
given in footnotes and repeated as referencesat the end of the document A reference to apublication is likely to be made for one of twomain reasons The publication may containadditional or more comprehensive technicaldetail which it would be impractical toinclude in full in the Approved Document butwhich is needed to fully explain ways ofmeeting the requirements or it is a source ofmore general information The reason for thereference will be indicated in each case Thereference will be to a specified edition of thedocument The Approved Document may beamended from time to time to include newreferences or to refer to revised editionswhere this aids compliance
d Additional commentary in italic text appearsafter some numbered paragraphs Thiscommentary is intended to assist understandingof the immediately preceding paragraph orsub-paragraph or to direct readers tosources of additional information but is notpart of the technical guidance itself
Where you can get further help
110 If you do not understand the technical
guidance or other information set out in this Approved Document and the additional detailedtechnical references to which it directs you thereare a number of routes through which you canseek further assistance
bull the Department for Communities andLocal Government websitewwwcommunitiesgovuk
bull the Planning Portal websitewwwplanningportalgovuk
bull if you are the person undertaking the buildingwork you can seek assistance either from
your local authority building control service orfrom your approved inspector (depending onwhich building control service you are using
bull persons registered with a competent personself-certification scheme may be able to gettechnical advice from their scheme operator
bull if your query is of a highly technical natureyou may wish to seek the advice of aspecialist or industry technical body forthe relevant subject
Responsibility for compliance111 It is important to remember that if youare the person (eg designer builder installer)carrying out building work to which anyrequirement of building regulations applies youhave a responsibility to ensure that the workcomplies with any such requirement The buildingowner may also have a responsibility for ensuringcompliance with building regulation requirementsand could be served with an enforcement noticein cases of non-compliance
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Conservation of fuel and power Approved Document L1B
L1B
21 This Approved Document which takeseffect on 1 October 2010 deals with the energyefficiency requirements in the BuildingRegulations Regulation 2(1) of the BuildingRegulations defines the energy efficiency requirements as the requirements of regulations23 26 28 40 and Part L of Schedule 1 Theenergy efficiency requirements relevantto existing dwellings are in regulations 23 28 29and 40 of and Part L of Schedule 1 to thoseRegulations as set out below
Requirements relating to thermal elements ndash Regulation 23
(1) Where a person intends to renovate a thermal element
such work shall be carried out as is necessary to ensure that the
whole thermal element complies with the requirements of
paragraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the new thermal
element shall comply with the requirements of paragraph L1(a)
(i) of Schedule 1
Consequential improvements to energy performance
Regulation 28
(1) Paragraph (2) applies to an existing building with a total
useful floor area over 1000 m2 where the proposed building
work consists of or includesmdash
(a) an extension
(b) the initial provision of any fixed building services or
(c) an increase to the installed capacity of any fixed
building services
(2) Subject to paragraph (3) where this paragraph applies
such work if any shall be carried out as is necessary to ensure
that the building complies with the requirements of Part L of
Schedule 1
(3) Nothing in paragraph (2) requires work to be carried out if
it is not technically functionally or economically feasible
Energy performance certificates ndash Regulation 29
(1) This regulation applies wheremdash
(a) a building is erected or
(b) a building is modified so that it has a greater or fewer
number of parts designed or altered for separate use than it
previously had where the modif ication includes the provision
or extension of any of the fixed services for heating hot water
air conditioning or mechanical ventilation
(2) The person carrying out the work shallmdash
(a) give an energy performance certificate for the building
to the owner of the building and
(b) give to the local authority notice to that effect
including the reference number under which the energy
performance certificate has been registered in accordance withregulation 17F(4)
Section 2 The requirements
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Approved Document L1B Conservation of fuel and power
THE REQUIREMENTS L1B
Energy performance certificates ndash Regulation 29 (continued)
(3) The energy performance certificate and notice shall be
given not later than f ive days after the work has been completed
(4) An energy performance certificate mustmdash
(a) express the asset rating of the building in a way
approved by the Secretary of State under regulation 24
(b) include a reference value such as a current legal
standard or benchmark
(c) be issued by an energy assessor who is accredited to
produce energy performance certificates for that category of
building and
(d) include the following informationmdash
(i) the reference number under which the certificate
has been registered in accordance with regulation 30(4)
(ii) the address of the building
(iii) an estimate of the total useful floor area of the
building
(iv) the name of the energy assessor who issued it
(v) the name and address of the energy assessorrsquos
employer or if he is self-employed the name under which he
trades and his address
(vi) the date on which it was issued and
(vii) the name of the approved accreditation scheme of
which the energy assessor is a member
(5) The energy performance certificate must be accompanied
by a recommendation report containing recommendations for
the improvement of the energy performance of the building
issued by the energy assessor who issued the energy
performance certificate
(6) Certification for apartments or units designed or alteredfor separate use in blocks may be basedmdash
(a) except in the case of a dwelling on a common
certification of the whole building for blocks with a common
heating system or
(b) on the assessment of another representative apartment
or unit in the same block
(7) Wheremdash
(a) a block with a common heating system is divided into
parts designed or altered for separate use and
(b) one or more but not all of the parts are dwellings
certification for those parts which are not dwellings may be based on a common certification of all the parts which are not
dwellings
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L1B THE REQUIREMENTS
6
Conservation of fuel and power Approved Document L1B
Requirement Limits on application
Schedule 1 ndash Part L Conservation of fuel and power
L1 Reasonable provision shall be made for the conservation of
fuel and power in buildings by
(a) limiting heat gains and lossesmdash
(i) through thermal elements and other parts of the
building fabric and
(ii) from pipes ducts and vessels used for space
heating space cooling and hot water services
(b) providing fixed building services whichmdash
(i) are energy efficient
(ii) have effective controls and
(iii) are commissioned by testing and adjusting as
necessary to ensure they use no more fuel and power than is
reasonable in the circumstances and
Regulation 40 providing to the owner sufficient informationabout the building the fixed building services and their
maintenance requirements so that the building can be operated
in such a manner as to use no more fuel and power than is
reasonable in the circumstances
LIMITATION ON REQUIREMENTS
22 In accordance with regulation 8 of theBuilding Regulations the requirements in Parts Ato D F to K and N (except for paragraphs G2 H2and J7) of Schedule 1 to the Building Regulations
do not require anything to be done except for thepurpose of securing reasonable standards ofhealth and safety for persons in or about buildings(and any others who may be affected by buildingsor matters connected with buildings)
23 Paragraph G2 is excluded as it deals withwater efficiency and paragraphs H2 and J7 areexcluded from regulation 8 because they dealdirectly with prevention of the contamination ofwater Parts E and M (which deal respectivelywith resistance to the passage of sound andaccess to and use of buildings) are excludedfrom regulation 8 because they address the
welfare and convenience of building users Part Lis excluded from regulation 8 because it addressesthe conservation of fuel and power
24 In addition regulation 4(2) of the BuildingRegulations states that where the work is beingcarried out in order to comply with regulation 23(requirements relating to renovation or replacementof a thermal element ) regulation 22 (requirementsrelating to a change of a buildingrsquos energy status)or regulation 28 ( consequential improvements to energy performance) and is not a materialalteration it need comply only with the requirementsof Part L
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Approved Document L1B Conservation of fuel and power
L1B
Key terms
31 The following are key terms used in thisdocument
BCB means Building Control Body a local
authority or an approved inspectorCommissioning means the advancement ofa fixed building service following installationreplacement or alteration of the whole or partof the system from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances without prejudice to the needto comply with health and safety requirementsFor each system commissioning includessetting-to-work regulation (that is testing andadjusting repetitively) to achieve the specified
performance the calibration setting up andtesting of the associated automatic controlsystems and recording of the system settingsand the performance test results that have beenaccepted as satisfactory
Consequential improvements means thoseenergy efficiency improvements required byregulation 28
Controlled service or fitting means a service orfitting in relation to which Part G (sanitation hotwater safety and water efficiency) H (drainageand waste disposal) J (combustion appliancesand fuel storage systems) L (conservation of fuel
and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement
Dwelling means a self-contained unit includinga house or a flat designed to be used separatelyto accommodate a single household ( Rooms for residential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings)
Energy efficiency requirements means therequirements of regulations 23 26 28 29 and40 of and Part L of Schedule 1 to the BuildingRegulations
In respect of existing dwellings the applicable requirements consist of Part L and regulations 23 38 and 40
Fixed building services means any part of orany controls associated with
a fixed internal or external lighting systems butdoes not include emergency escape lightingor specialist process lighting or
b fixed systems for heating hot water airconditioning or mechanical ventilation
Room for residential purposes means a room ora suite of rooms which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel anhotel a boarding house a hall of residence or a
residential home but does not include a room in ahospital or other similar establishment used forpatient accommodation
lsquo Renovationrsquo in relation to a thermal elementmeans the provision of a new layer in the thermalelement (other than where that new layer isprovided solely as a means of repair to a flatroof) or the replacement of an existing layer butexcludes decorative finishes and lsquorenovatersquo shallbe construed accordingly
Simple payback means the amount of time itwill take to recover the initial investment through
energy savings and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT When making thiscalculation the following guidance should be used
a the marginal additional cost is the additionalcost (materials and labour) of incorporating(eg) additional insulation not the whole costof the work
b the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to the BCB andbe confirmed in a report signed by a suitablyqualified person
c the annual energy savings should beestimated using SAP 20091
d for the purposes of this Approved Documentthe energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings Current energy prices can be obtainedfrom the DECC website2
Thermal element is defined in regulation 2(3)of the Building Regulations as follows
2(3) In these Regulations lsquothermal elementrsquomeans a wall floor or roof (but does not includewindows doors roof windows or roof-lights)which separates a thermally conditioned part ofthe building (lsquothe conditioned spacersquo) from
a the external environment (including theground) or
b in the case of floors and walls another part ofthe building which is
i unconditioned
1 wwwbrecouksap20092 wwwdeccgovukencontentcmsstatisticspublicationpricespricesaspx
Section 3 General guidance
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Conservation of fuel and power Approved Document L1B
L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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GENERAL GUIDANCE L1B
9
Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Approved Document L1B Conservation of fuel and power
INTRODUCTION L1B
19 In this document the following conventionshave been adopted to assist understanding andinterpretation
a Texts shown against a green background areextracts from the Building Regulations 2010(SI 20102214) or Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)and set out the legal requirements that relateto compliance with the energy efficiency requirements of building regulations As statedpreviously there is no flexibility in respect ofsuch text it defines a legal requirement notguidance for typical situations It should alsobe remembered that as noted abovebuilding works must comply with all the otherapplicable requirements of building regulations
b Key terms are defined in paragraph 31 andare printed in bold italic text
c Details of technical publications referred toin the text of this Approved Document will be
given in footnotes and repeated as referencesat the end of the document A reference to apublication is likely to be made for one of twomain reasons The publication may containadditional or more comprehensive technicaldetail which it would be impractical toinclude in full in the Approved Document butwhich is needed to fully explain ways ofmeeting the requirements or it is a source ofmore general information The reason for thereference will be indicated in each case Thereference will be to a specified edition of thedocument The Approved Document may beamended from time to time to include newreferences or to refer to revised editionswhere this aids compliance
d Additional commentary in italic text appearsafter some numbered paragraphs Thiscommentary is intended to assist understandingof the immediately preceding paragraph orsub-paragraph or to direct readers tosources of additional information but is notpart of the technical guidance itself
Where you can get further help
110 If you do not understand the technical
guidance or other information set out in this Approved Document and the additional detailedtechnical references to which it directs you thereare a number of routes through which you canseek further assistance
bull the Department for Communities andLocal Government websitewwwcommunitiesgovuk
bull the Planning Portal websitewwwplanningportalgovuk
bull if you are the person undertaking the buildingwork you can seek assistance either from
your local authority building control service orfrom your approved inspector (depending onwhich building control service you are using
bull persons registered with a competent personself-certification scheme may be able to gettechnical advice from their scheme operator
bull if your query is of a highly technical natureyou may wish to seek the advice of aspecialist or industry technical body forthe relevant subject
Responsibility for compliance111 It is important to remember that if youare the person (eg designer builder installer)carrying out building work to which anyrequirement of building regulations applies youhave a responsibility to ensure that the workcomplies with any such requirement The buildingowner may also have a responsibility for ensuringcompliance with building regulation requirementsand could be served with an enforcement noticein cases of non-compliance
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Conservation of fuel and power Approved Document L1B
L1B
21 This Approved Document which takeseffect on 1 October 2010 deals with the energyefficiency requirements in the BuildingRegulations Regulation 2(1) of the BuildingRegulations defines the energy efficiency requirements as the requirements of regulations23 26 28 40 and Part L of Schedule 1 Theenergy efficiency requirements relevantto existing dwellings are in regulations 23 28 29and 40 of and Part L of Schedule 1 to thoseRegulations as set out below
Requirements relating to thermal elements ndash Regulation 23
(1) Where a person intends to renovate a thermal element
such work shall be carried out as is necessary to ensure that the
whole thermal element complies with the requirements of
paragraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the new thermal
element shall comply with the requirements of paragraph L1(a)
(i) of Schedule 1
Consequential improvements to energy performance
Regulation 28
(1) Paragraph (2) applies to an existing building with a total
useful floor area over 1000 m2 where the proposed building
work consists of or includesmdash
(a) an extension
(b) the initial provision of any fixed building services or
(c) an increase to the installed capacity of any fixed
building services
(2) Subject to paragraph (3) where this paragraph applies
such work if any shall be carried out as is necessary to ensure
that the building complies with the requirements of Part L of
Schedule 1
(3) Nothing in paragraph (2) requires work to be carried out if
it is not technically functionally or economically feasible
Energy performance certificates ndash Regulation 29
(1) This regulation applies wheremdash
(a) a building is erected or
(b) a building is modified so that it has a greater or fewer
number of parts designed or altered for separate use than it
previously had where the modif ication includes the provision
or extension of any of the fixed services for heating hot water
air conditioning or mechanical ventilation
(2) The person carrying out the work shallmdash
(a) give an energy performance certificate for the building
to the owner of the building and
(b) give to the local authority notice to that effect
including the reference number under which the energy
performance certificate has been registered in accordance withregulation 17F(4)
Section 2 The requirements
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Approved Document L1B Conservation of fuel and power
THE REQUIREMENTS L1B
Energy performance certificates ndash Regulation 29 (continued)
(3) The energy performance certificate and notice shall be
given not later than f ive days after the work has been completed
(4) An energy performance certificate mustmdash
(a) express the asset rating of the building in a way
approved by the Secretary of State under regulation 24
(b) include a reference value such as a current legal
standard or benchmark
(c) be issued by an energy assessor who is accredited to
produce energy performance certificates for that category of
building and
(d) include the following informationmdash
(i) the reference number under which the certificate
has been registered in accordance with regulation 30(4)
(ii) the address of the building
(iii) an estimate of the total useful floor area of the
building
(iv) the name of the energy assessor who issued it
(v) the name and address of the energy assessorrsquos
employer or if he is self-employed the name under which he
trades and his address
(vi) the date on which it was issued and
(vii) the name of the approved accreditation scheme of
which the energy assessor is a member
(5) The energy performance certificate must be accompanied
by a recommendation report containing recommendations for
the improvement of the energy performance of the building
issued by the energy assessor who issued the energy
performance certificate
(6) Certification for apartments or units designed or alteredfor separate use in blocks may be basedmdash
(a) except in the case of a dwelling on a common
certification of the whole building for blocks with a common
heating system or
(b) on the assessment of another representative apartment
or unit in the same block
(7) Wheremdash
(a) a block with a common heating system is divided into
parts designed or altered for separate use and
(b) one or more but not all of the parts are dwellings
certification for those parts which are not dwellings may be based on a common certification of all the parts which are not
dwellings
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L1B THE REQUIREMENTS
6
Conservation of fuel and power Approved Document L1B
Requirement Limits on application
Schedule 1 ndash Part L Conservation of fuel and power
L1 Reasonable provision shall be made for the conservation of
fuel and power in buildings by
(a) limiting heat gains and lossesmdash
(i) through thermal elements and other parts of the
building fabric and
(ii) from pipes ducts and vessels used for space
heating space cooling and hot water services
(b) providing fixed building services whichmdash
(i) are energy efficient
(ii) have effective controls and
(iii) are commissioned by testing and adjusting as
necessary to ensure they use no more fuel and power than is
reasonable in the circumstances and
Regulation 40 providing to the owner sufficient informationabout the building the fixed building services and their
maintenance requirements so that the building can be operated
in such a manner as to use no more fuel and power than is
reasonable in the circumstances
LIMITATION ON REQUIREMENTS
22 In accordance with regulation 8 of theBuilding Regulations the requirements in Parts Ato D F to K and N (except for paragraphs G2 H2and J7) of Schedule 1 to the Building Regulations
do not require anything to be done except for thepurpose of securing reasonable standards ofhealth and safety for persons in or about buildings(and any others who may be affected by buildingsor matters connected with buildings)
23 Paragraph G2 is excluded as it deals withwater efficiency and paragraphs H2 and J7 areexcluded from regulation 8 because they dealdirectly with prevention of the contamination ofwater Parts E and M (which deal respectivelywith resistance to the passage of sound andaccess to and use of buildings) are excludedfrom regulation 8 because they address the
welfare and convenience of building users Part Lis excluded from regulation 8 because it addressesthe conservation of fuel and power
24 In addition regulation 4(2) of the BuildingRegulations states that where the work is beingcarried out in order to comply with regulation 23(requirements relating to renovation or replacementof a thermal element ) regulation 22 (requirementsrelating to a change of a buildingrsquos energy status)or regulation 28 ( consequential improvements to energy performance) and is not a materialalteration it need comply only with the requirementsof Part L
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Approved Document L1B Conservation of fuel and power
L1B
Key terms
31 The following are key terms used in thisdocument
BCB means Building Control Body a local
authority or an approved inspectorCommissioning means the advancement ofa fixed building service following installationreplacement or alteration of the whole or partof the system from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances without prejudice to the needto comply with health and safety requirementsFor each system commissioning includessetting-to-work regulation (that is testing andadjusting repetitively) to achieve the specified
performance the calibration setting up andtesting of the associated automatic controlsystems and recording of the system settingsand the performance test results that have beenaccepted as satisfactory
Consequential improvements means thoseenergy efficiency improvements required byregulation 28
Controlled service or fitting means a service orfitting in relation to which Part G (sanitation hotwater safety and water efficiency) H (drainageand waste disposal) J (combustion appliancesand fuel storage systems) L (conservation of fuel
and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement
Dwelling means a self-contained unit includinga house or a flat designed to be used separatelyto accommodate a single household ( Rooms for residential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings)
Energy efficiency requirements means therequirements of regulations 23 26 28 29 and40 of and Part L of Schedule 1 to the BuildingRegulations
In respect of existing dwellings the applicable requirements consist of Part L and regulations 23 38 and 40
Fixed building services means any part of orany controls associated with
a fixed internal or external lighting systems butdoes not include emergency escape lightingor specialist process lighting or
b fixed systems for heating hot water airconditioning or mechanical ventilation
Room for residential purposes means a room ora suite of rooms which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel anhotel a boarding house a hall of residence or a
residential home but does not include a room in ahospital or other similar establishment used forpatient accommodation
lsquo Renovationrsquo in relation to a thermal elementmeans the provision of a new layer in the thermalelement (other than where that new layer isprovided solely as a means of repair to a flatroof) or the replacement of an existing layer butexcludes decorative finishes and lsquorenovatersquo shallbe construed accordingly
Simple payback means the amount of time itwill take to recover the initial investment through
energy savings and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT When making thiscalculation the following guidance should be used
a the marginal additional cost is the additionalcost (materials and labour) of incorporating(eg) additional insulation not the whole costof the work
b the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to the BCB andbe confirmed in a report signed by a suitablyqualified person
c the annual energy savings should beestimated using SAP 20091
d for the purposes of this Approved Documentthe energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings Current energy prices can be obtainedfrom the DECC website2
Thermal element is defined in regulation 2(3)of the Building Regulations as follows
2(3) In these Regulations lsquothermal elementrsquomeans a wall floor or roof (but does not includewindows doors roof windows or roof-lights)which separates a thermally conditioned part ofthe building (lsquothe conditioned spacersquo) from
a the external environment (including theground) or
b in the case of floors and walls another part ofthe building which is
i unconditioned
1 wwwbrecouksap20092 wwwdeccgovukencontentcmsstatisticspublicationpricespricesaspx
Section 3 General guidance
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L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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GENERAL GUIDANCE L1B
9
Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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L1B GENERAL GUIDANCE
10
Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
11
Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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Conservation of fuel and power Approved Document L1B
L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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Approved Document L1B Conservation of fuel and power
GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Conservation of fuel and power Approved Document L1B
L1B
21 This Approved Document which takeseffect on 1 October 2010 deals with the energyefficiency requirements in the BuildingRegulations Regulation 2(1) of the BuildingRegulations defines the energy efficiency requirements as the requirements of regulations23 26 28 40 and Part L of Schedule 1 Theenergy efficiency requirements relevantto existing dwellings are in regulations 23 28 29and 40 of and Part L of Schedule 1 to thoseRegulations as set out below
Requirements relating to thermal elements ndash Regulation 23
(1) Where a person intends to renovate a thermal element
such work shall be carried out as is necessary to ensure that the
whole thermal element complies with the requirements of
paragraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the new thermal
element shall comply with the requirements of paragraph L1(a)
(i) of Schedule 1
Consequential improvements to energy performance
Regulation 28
(1) Paragraph (2) applies to an existing building with a total
useful floor area over 1000 m2 where the proposed building
work consists of or includesmdash
(a) an extension
(b) the initial provision of any fixed building services or
(c) an increase to the installed capacity of any fixed
building services
(2) Subject to paragraph (3) where this paragraph applies
such work if any shall be carried out as is necessary to ensure
that the building complies with the requirements of Part L of
Schedule 1
(3) Nothing in paragraph (2) requires work to be carried out if
it is not technically functionally or economically feasible
Energy performance certificates ndash Regulation 29
(1) This regulation applies wheremdash
(a) a building is erected or
(b) a building is modified so that it has a greater or fewer
number of parts designed or altered for separate use than it
previously had where the modif ication includes the provision
or extension of any of the fixed services for heating hot water
air conditioning or mechanical ventilation
(2) The person carrying out the work shallmdash
(a) give an energy performance certificate for the building
to the owner of the building and
(b) give to the local authority notice to that effect
including the reference number under which the energy
performance certificate has been registered in accordance withregulation 17F(4)
Section 2 The requirements
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Approved Document L1B Conservation of fuel and power
THE REQUIREMENTS L1B
Energy performance certificates ndash Regulation 29 (continued)
(3) The energy performance certificate and notice shall be
given not later than f ive days after the work has been completed
(4) An energy performance certificate mustmdash
(a) express the asset rating of the building in a way
approved by the Secretary of State under regulation 24
(b) include a reference value such as a current legal
standard or benchmark
(c) be issued by an energy assessor who is accredited to
produce energy performance certificates for that category of
building and
(d) include the following informationmdash
(i) the reference number under which the certificate
has been registered in accordance with regulation 30(4)
(ii) the address of the building
(iii) an estimate of the total useful floor area of the
building
(iv) the name of the energy assessor who issued it
(v) the name and address of the energy assessorrsquos
employer or if he is self-employed the name under which he
trades and his address
(vi) the date on which it was issued and
(vii) the name of the approved accreditation scheme of
which the energy assessor is a member
(5) The energy performance certificate must be accompanied
by a recommendation report containing recommendations for
the improvement of the energy performance of the building
issued by the energy assessor who issued the energy
performance certificate
(6) Certification for apartments or units designed or alteredfor separate use in blocks may be basedmdash
(a) except in the case of a dwelling on a common
certification of the whole building for blocks with a common
heating system or
(b) on the assessment of another representative apartment
or unit in the same block
(7) Wheremdash
(a) a block with a common heating system is divided into
parts designed or altered for separate use and
(b) one or more but not all of the parts are dwellings
certification for those parts which are not dwellings may be based on a common certification of all the parts which are not
dwellings
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L1B THE REQUIREMENTS
6
Conservation of fuel and power Approved Document L1B
Requirement Limits on application
Schedule 1 ndash Part L Conservation of fuel and power
L1 Reasonable provision shall be made for the conservation of
fuel and power in buildings by
(a) limiting heat gains and lossesmdash
(i) through thermal elements and other parts of the
building fabric and
(ii) from pipes ducts and vessels used for space
heating space cooling and hot water services
(b) providing fixed building services whichmdash
(i) are energy efficient
(ii) have effective controls and
(iii) are commissioned by testing and adjusting as
necessary to ensure they use no more fuel and power than is
reasonable in the circumstances and
Regulation 40 providing to the owner sufficient informationabout the building the fixed building services and their
maintenance requirements so that the building can be operated
in such a manner as to use no more fuel and power than is
reasonable in the circumstances
LIMITATION ON REQUIREMENTS
22 In accordance with regulation 8 of theBuilding Regulations the requirements in Parts Ato D F to K and N (except for paragraphs G2 H2and J7) of Schedule 1 to the Building Regulations
do not require anything to be done except for thepurpose of securing reasonable standards ofhealth and safety for persons in or about buildings(and any others who may be affected by buildingsor matters connected with buildings)
23 Paragraph G2 is excluded as it deals withwater efficiency and paragraphs H2 and J7 areexcluded from regulation 8 because they dealdirectly with prevention of the contamination ofwater Parts E and M (which deal respectivelywith resistance to the passage of sound andaccess to and use of buildings) are excludedfrom regulation 8 because they address the
welfare and convenience of building users Part Lis excluded from regulation 8 because it addressesthe conservation of fuel and power
24 In addition regulation 4(2) of the BuildingRegulations states that where the work is beingcarried out in order to comply with regulation 23(requirements relating to renovation or replacementof a thermal element ) regulation 22 (requirementsrelating to a change of a buildingrsquos energy status)or regulation 28 ( consequential improvements to energy performance) and is not a materialalteration it need comply only with the requirementsof Part L
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Approved Document L1B Conservation of fuel and power
L1B
Key terms
31 The following are key terms used in thisdocument
BCB means Building Control Body a local
authority or an approved inspectorCommissioning means the advancement ofa fixed building service following installationreplacement or alteration of the whole or partof the system from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances without prejudice to the needto comply with health and safety requirementsFor each system commissioning includessetting-to-work regulation (that is testing andadjusting repetitively) to achieve the specified
performance the calibration setting up andtesting of the associated automatic controlsystems and recording of the system settingsand the performance test results that have beenaccepted as satisfactory
Consequential improvements means thoseenergy efficiency improvements required byregulation 28
Controlled service or fitting means a service orfitting in relation to which Part G (sanitation hotwater safety and water efficiency) H (drainageand waste disposal) J (combustion appliancesand fuel storage systems) L (conservation of fuel
and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement
Dwelling means a self-contained unit includinga house or a flat designed to be used separatelyto accommodate a single household ( Rooms for residential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings)
Energy efficiency requirements means therequirements of regulations 23 26 28 29 and40 of and Part L of Schedule 1 to the BuildingRegulations
In respect of existing dwellings the applicable requirements consist of Part L and regulations 23 38 and 40
Fixed building services means any part of orany controls associated with
a fixed internal or external lighting systems butdoes not include emergency escape lightingor specialist process lighting or
b fixed systems for heating hot water airconditioning or mechanical ventilation
Room for residential purposes means a room ora suite of rooms which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel anhotel a boarding house a hall of residence or a
residential home but does not include a room in ahospital or other similar establishment used forpatient accommodation
lsquo Renovationrsquo in relation to a thermal elementmeans the provision of a new layer in the thermalelement (other than where that new layer isprovided solely as a means of repair to a flatroof) or the replacement of an existing layer butexcludes decorative finishes and lsquorenovatersquo shallbe construed accordingly
Simple payback means the amount of time itwill take to recover the initial investment through
energy savings and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT When making thiscalculation the following guidance should be used
a the marginal additional cost is the additionalcost (materials and labour) of incorporating(eg) additional insulation not the whole costof the work
b the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to the BCB andbe confirmed in a report signed by a suitablyqualified person
c the annual energy savings should beestimated using SAP 20091
d for the purposes of this Approved Documentthe energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings Current energy prices can be obtainedfrom the DECC website2
Thermal element is defined in regulation 2(3)of the Building Regulations as follows
2(3) In these Regulations lsquothermal elementrsquomeans a wall floor or roof (but does not includewindows doors roof windows or roof-lights)which separates a thermally conditioned part ofthe building (lsquothe conditioned spacersquo) from
a the external environment (including theground) or
b in the case of floors and walls another part ofthe building which is
i unconditioned
1 wwwbrecouksap20092 wwwdeccgovukencontentcmsstatisticspublicationpricespricesaspx
Section 3 General guidance
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Conservation of fuel and power Approved Document L1B
L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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GENERAL GUIDANCE L1B
9
Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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L1B GENERAL GUIDANCE
10
Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Approved Document L1B Conservation of fuel and power
THE REQUIREMENTS L1B
Energy performance certificates ndash Regulation 29 (continued)
(3) The energy performance certificate and notice shall be
given not later than f ive days after the work has been completed
(4) An energy performance certificate mustmdash
(a) express the asset rating of the building in a way
approved by the Secretary of State under regulation 24
(b) include a reference value such as a current legal
standard or benchmark
(c) be issued by an energy assessor who is accredited to
produce energy performance certificates for that category of
building and
(d) include the following informationmdash
(i) the reference number under which the certificate
has been registered in accordance with regulation 30(4)
(ii) the address of the building
(iii) an estimate of the total useful floor area of the
building
(iv) the name of the energy assessor who issued it
(v) the name and address of the energy assessorrsquos
employer or if he is self-employed the name under which he
trades and his address
(vi) the date on which it was issued and
(vii) the name of the approved accreditation scheme of
which the energy assessor is a member
(5) The energy performance certificate must be accompanied
by a recommendation report containing recommendations for
the improvement of the energy performance of the building
issued by the energy assessor who issued the energy
performance certificate
(6) Certification for apartments or units designed or alteredfor separate use in blocks may be basedmdash
(a) except in the case of a dwelling on a common
certification of the whole building for blocks with a common
heating system or
(b) on the assessment of another representative apartment
or unit in the same block
(7) Wheremdash
(a) a block with a common heating system is divided into
parts designed or altered for separate use and
(b) one or more but not all of the parts are dwellings
certification for those parts which are not dwellings may be based on a common certification of all the parts which are not
dwellings
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L1B THE REQUIREMENTS
6
Conservation of fuel and power Approved Document L1B
Requirement Limits on application
Schedule 1 ndash Part L Conservation of fuel and power
L1 Reasonable provision shall be made for the conservation of
fuel and power in buildings by
(a) limiting heat gains and lossesmdash
(i) through thermal elements and other parts of the
building fabric and
(ii) from pipes ducts and vessels used for space
heating space cooling and hot water services
(b) providing fixed building services whichmdash
(i) are energy efficient
(ii) have effective controls and
(iii) are commissioned by testing and adjusting as
necessary to ensure they use no more fuel and power than is
reasonable in the circumstances and
Regulation 40 providing to the owner sufficient informationabout the building the fixed building services and their
maintenance requirements so that the building can be operated
in such a manner as to use no more fuel and power than is
reasonable in the circumstances
LIMITATION ON REQUIREMENTS
22 In accordance with regulation 8 of theBuilding Regulations the requirements in Parts Ato D F to K and N (except for paragraphs G2 H2and J7) of Schedule 1 to the Building Regulations
do not require anything to be done except for thepurpose of securing reasonable standards ofhealth and safety for persons in or about buildings(and any others who may be affected by buildingsor matters connected with buildings)
23 Paragraph G2 is excluded as it deals withwater efficiency and paragraphs H2 and J7 areexcluded from regulation 8 because they dealdirectly with prevention of the contamination ofwater Parts E and M (which deal respectivelywith resistance to the passage of sound andaccess to and use of buildings) are excludedfrom regulation 8 because they address the
welfare and convenience of building users Part Lis excluded from regulation 8 because it addressesthe conservation of fuel and power
24 In addition regulation 4(2) of the BuildingRegulations states that where the work is beingcarried out in order to comply with regulation 23(requirements relating to renovation or replacementof a thermal element ) regulation 22 (requirementsrelating to a change of a buildingrsquos energy status)or regulation 28 ( consequential improvements to energy performance) and is not a materialalteration it need comply only with the requirementsof Part L
I N E V E R I N
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Approved Document L1B Conservation of fuel and power
L1B
Key terms
31 The following are key terms used in thisdocument
BCB means Building Control Body a local
authority or an approved inspectorCommissioning means the advancement ofa fixed building service following installationreplacement or alteration of the whole or partof the system from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances without prejudice to the needto comply with health and safety requirementsFor each system commissioning includessetting-to-work regulation (that is testing andadjusting repetitively) to achieve the specified
performance the calibration setting up andtesting of the associated automatic controlsystems and recording of the system settingsand the performance test results that have beenaccepted as satisfactory
Consequential improvements means thoseenergy efficiency improvements required byregulation 28
Controlled service or fitting means a service orfitting in relation to which Part G (sanitation hotwater safety and water efficiency) H (drainageand waste disposal) J (combustion appliancesand fuel storage systems) L (conservation of fuel
and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement
Dwelling means a self-contained unit includinga house or a flat designed to be used separatelyto accommodate a single household ( Rooms for residential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings)
Energy efficiency requirements means therequirements of regulations 23 26 28 29 and40 of and Part L of Schedule 1 to the BuildingRegulations
In respect of existing dwellings the applicable requirements consist of Part L and regulations 23 38 and 40
Fixed building services means any part of orany controls associated with
a fixed internal or external lighting systems butdoes not include emergency escape lightingor specialist process lighting or
b fixed systems for heating hot water airconditioning or mechanical ventilation
Room for residential purposes means a room ora suite of rooms which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel anhotel a boarding house a hall of residence or a
residential home but does not include a room in ahospital or other similar establishment used forpatient accommodation
lsquo Renovationrsquo in relation to a thermal elementmeans the provision of a new layer in the thermalelement (other than where that new layer isprovided solely as a means of repair to a flatroof) or the replacement of an existing layer butexcludes decorative finishes and lsquorenovatersquo shallbe construed accordingly
Simple payback means the amount of time itwill take to recover the initial investment through
energy savings and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT When making thiscalculation the following guidance should be used
a the marginal additional cost is the additionalcost (materials and labour) of incorporating(eg) additional insulation not the whole costof the work
b the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to the BCB andbe confirmed in a report signed by a suitablyqualified person
c the annual energy savings should beestimated using SAP 20091
d for the purposes of this Approved Documentthe energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings Current energy prices can be obtainedfrom the DECC website2
Thermal element is defined in regulation 2(3)of the Building Regulations as follows
2(3) In these Regulations lsquothermal elementrsquomeans a wall floor or roof (but does not includewindows doors roof windows or roof-lights)which separates a thermally conditioned part ofthe building (lsquothe conditioned spacersquo) from
a the external environment (including theground) or
b in the case of floors and walls another part ofthe building which is
i unconditioned
1 wwwbrecouksap20092 wwwdeccgovukencontentcmsstatisticspublicationpricespricesaspx
Section 3 General guidance
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L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
11
Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Conservation of fuel and power Approved Document L1B
Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
N
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GUIDANCE RELATING TO BUILDING WORK L1B
15
Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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L1B GUIDANCE RELATING TO BUILDING WORK
16
Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
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ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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L1B THE REQUIREMENTS
6
Conservation of fuel and power Approved Document L1B
Requirement Limits on application
Schedule 1 ndash Part L Conservation of fuel and power
L1 Reasonable provision shall be made for the conservation of
fuel and power in buildings by
(a) limiting heat gains and lossesmdash
(i) through thermal elements and other parts of the
building fabric and
(ii) from pipes ducts and vessels used for space
heating space cooling and hot water services
(b) providing fixed building services whichmdash
(i) are energy efficient
(ii) have effective controls and
(iii) are commissioned by testing and adjusting as
necessary to ensure they use no more fuel and power than is
reasonable in the circumstances and
Regulation 40 providing to the owner sufficient informationabout the building the fixed building services and their
maintenance requirements so that the building can be operated
in such a manner as to use no more fuel and power than is
reasonable in the circumstances
LIMITATION ON REQUIREMENTS
22 In accordance with regulation 8 of theBuilding Regulations the requirements in Parts Ato D F to K and N (except for paragraphs G2 H2and J7) of Schedule 1 to the Building Regulations
do not require anything to be done except for thepurpose of securing reasonable standards ofhealth and safety for persons in or about buildings(and any others who may be affected by buildingsor matters connected with buildings)
23 Paragraph G2 is excluded as it deals withwater efficiency and paragraphs H2 and J7 areexcluded from regulation 8 because they dealdirectly with prevention of the contamination ofwater Parts E and M (which deal respectivelywith resistance to the passage of sound andaccess to and use of buildings) are excludedfrom regulation 8 because they address the
welfare and convenience of building users Part Lis excluded from regulation 8 because it addressesthe conservation of fuel and power
24 In addition regulation 4(2) of the BuildingRegulations states that where the work is beingcarried out in order to comply with regulation 23(requirements relating to renovation or replacementof a thermal element ) regulation 22 (requirementsrelating to a change of a buildingrsquos energy status)or regulation 28 ( consequential improvements to energy performance) and is not a materialalteration it need comply only with the requirementsof Part L
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Approved Document L1B Conservation of fuel and power
L1B
Key terms
31 The following are key terms used in thisdocument
BCB means Building Control Body a local
authority or an approved inspectorCommissioning means the advancement ofa fixed building service following installationreplacement or alteration of the whole or partof the system from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances without prejudice to the needto comply with health and safety requirementsFor each system commissioning includessetting-to-work regulation (that is testing andadjusting repetitively) to achieve the specified
performance the calibration setting up andtesting of the associated automatic controlsystems and recording of the system settingsand the performance test results that have beenaccepted as satisfactory
Consequential improvements means thoseenergy efficiency improvements required byregulation 28
Controlled service or fitting means a service orfitting in relation to which Part G (sanitation hotwater safety and water efficiency) H (drainageand waste disposal) J (combustion appliancesand fuel storage systems) L (conservation of fuel
and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement
Dwelling means a self-contained unit includinga house or a flat designed to be used separatelyto accommodate a single household ( Rooms for residential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings)
Energy efficiency requirements means therequirements of regulations 23 26 28 29 and40 of and Part L of Schedule 1 to the BuildingRegulations
In respect of existing dwellings the applicable requirements consist of Part L and regulations 23 38 and 40
Fixed building services means any part of orany controls associated with
a fixed internal or external lighting systems butdoes not include emergency escape lightingor specialist process lighting or
b fixed systems for heating hot water airconditioning or mechanical ventilation
Room for residential purposes means a room ora suite of rooms which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel anhotel a boarding house a hall of residence or a
residential home but does not include a room in ahospital or other similar establishment used forpatient accommodation
lsquo Renovationrsquo in relation to a thermal elementmeans the provision of a new layer in the thermalelement (other than where that new layer isprovided solely as a means of repair to a flatroof) or the replacement of an existing layer butexcludes decorative finishes and lsquorenovatersquo shallbe construed accordingly
Simple payback means the amount of time itwill take to recover the initial investment through
energy savings and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT When making thiscalculation the following guidance should be used
a the marginal additional cost is the additionalcost (materials and labour) of incorporating(eg) additional insulation not the whole costof the work
b the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to the BCB andbe confirmed in a report signed by a suitablyqualified person
c the annual energy savings should beestimated using SAP 20091
d for the purposes of this Approved Documentthe energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings Current energy prices can be obtainedfrom the DECC website2
Thermal element is defined in regulation 2(3)of the Building Regulations as follows
2(3) In these Regulations lsquothermal elementrsquomeans a wall floor or roof (but does not includewindows doors roof windows or roof-lights)which separates a thermally conditioned part ofthe building (lsquothe conditioned spacersquo) from
a the external environment (including theground) or
b in the case of floors and walls another part ofthe building which is
i unconditioned
1 wwwbrecouksap20092 wwwdeccgovukencontentcmsstatisticspublicationpricespricesaspx
Section 3 General guidance
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Conservation of fuel and power Approved Document L1B
L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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GENERAL GUIDANCE L1B
9
Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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L1B GENERAL GUIDANCE
10
Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
11
Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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Conservation of fuel and power Approved Document L1B
L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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Approved Document L1B Conservation of fuel and power
GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Conservation of fuel and power Approved Document L1B
Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Approved Document L1B Conservation of fuel and power
L1B
Key terms
31 The following are key terms used in thisdocument
BCB means Building Control Body a local
authority or an approved inspectorCommissioning means the advancement ofa fixed building service following installationreplacement or alteration of the whole or partof the system from the state of static completionto working order by testing and adjusting asnecessary to ensure that the system as a wholeuses no more fuel and power than is reasonable inthe circumstances without prejudice to the needto comply with health and safety requirementsFor each system commissioning includessetting-to-work regulation (that is testing andadjusting repetitively) to achieve the specified
performance the calibration setting up andtesting of the associated automatic controlsystems and recording of the system settingsand the performance test results that have beenaccepted as satisfactory
Consequential improvements means thoseenergy efficiency improvements required byregulation 28
Controlled service or fitting means a service orfitting in relation to which Part G (sanitation hotwater safety and water efficiency) H (drainageand waste disposal) J (combustion appliancesand fuel storage systems) L (conservation of fuel
and power) or P (electrical safety) of Schedule 1to the Building Regulations imposes a requirement
Dwelling means a self-contained unit includinga house or a flat designed to be used separatelyto accommodate a single household ( Rooms for residential purposes are not dwellings so ApprovedDocument L2B applies to work in such buildings)
Energy efficiency requirements means therequirements of regulations 23 26 28 29 and40 of and Part L of Schedule 1 to the BuildingRegulations
In respect of existing dwellings the applicable requirements consist of Part L and regulations 23 38 and 40
Fixed building services means any part of orany controls associated with
a fixed internal or external lighting systems butdoes not include emergency escape lightingor specialist process lighting or
b fixed systems for heating hot water airconditioning or mechanical ventilation
Room for residential purposes means a room ora suite of rooms which is not a dwelling-house or aflat and which is used by one or more persons tolive and sleep and includes a room in a hostel anhotel a boarding house a hall of residence or a
residential home but does not include a room in ahospital or other similar establishment used forpatient accommodation
lsquo Renovationrsquo in relation to a thermal elementmeans the provision of a new layer in the thermalelement (other than where that new layer isprovided solely as a means of repair to a flatroof) or the replacement of an existing layer butexcludes decorative finishes and lsquorenovatersquo shallbe construed accordingly
Simple payback means the amount of time itwill take to recover the initial investment through
energy savings and is calculated by dividingthe marginal additional cost of implementing anenergy efficiency measure by the value of theannual energy savings achieved by that measuretaking no account of VAT When making thiscalculation the following guidance should be used
a the marginal additional cost is the additionalcost (materials and labour) of incorporating(eg) additional insulation not the whole costof the work
b the cost of implementing the measure shouldbe based on prices current at the date theproposals are made known to the BCB andbe confirmed in a report signed by a suitablyqualified person
c the annual energy savings should beestimated using SAP 20091
d for the purposes of this Approved Documentthe energy prices that are current at the timeof the application to building control shouldbe used when evaluating the annual energysavings Current energy prices can be obtainedfrom the DECC website2
Thermal element is defined in regulation 2(3)of the Building Regulations as follows
2(3) In these Regulations lsquothermal elementrsquomeans a wall floor or roof (but does not includewindows doors roof windows or roof-lights)which separates a thermally conditioned part ofthe building (lsquothe conditioned spacersquo) from
a the external environment (including theground) or
b in the case of floors and walls another part ofthe building which is
i unconditioned
1 wwwbrecouksap20092 wwwdeccgovukencontentcmsstatisticspublicationpricespricesaspx
Section 3 General guidance
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L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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GENERAL GUIDANCE L1B
9
Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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L1B GENERAL GUIDANCE
10
Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
11
Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Conservation of fuel and power Approved Document L1B
L1B GENERAL GUIDANCE
ii an extension falling within class VII inSchedule 2 or
iii where this paragraph applies conditionedto a different temperature
and includes all parts of the element between thesurface bounding the conditioned space and theexternal environment or other part of the building
as the case may be2(4) Paragraph 2(3)(b)(iii) only applies to a buildingwhich is not a dwelling where the other part ofthe building is used for a purpose which is notsimilar or identical to the purpose for which theconditioned space is used
Note that this definition encompasses the walls and floor of a swimming pool basin where this is part of an existing dwelling
Types of work covered by this
Approved Document
32 This Approved Document is intended togive guidance on what in ordinary circumstancesmay be considered reasonable provision forcompliance with the requirements of regulation23 and 28 of and Part L of Schedule 1 to theBuilding Regulations for those carrying outbuilding work to existing dwellings In addition itgives guidance on compliance with regulations43 44 and 27 of the Building Regulations and20(1) (4) and (6) of the Building (ApprovedInspectors etc) Regulations 2010 (SI 20102215)(lsquothe Approved Inspectors Regulationsrsquo)
Buildings exclusively containing rooms for residential purposes such as nursing homes student accommodation and similar are notdwellings and in such cases ApprovedDocument L2B applies
33 In particular this Approved Documentgives guidance on compliance with the energyefficiency requirements where the followingoccurs
a the construction of an extension (seeparagraphs 41 to 49)
b a material change of use or a change to the
buildingrsquos energy status including such workas loft and garage conversions (paragraphs411 to 416)
c the provision or extension of a controlled service or controlled fitting (paragraphs417 to 437)
d the replacement or renovation of a thermalelement (Section 5)
34 Where the activities include building workin a dwelling that is part of a mixed-use buildingaccount should also be taken of the guidance in Approved Document L2B in relation to those
parts of the building that are not dwellingsincluding any common areas
It should be noted that dwellings are defined as self-contained units Rooms for residential
purposes are not dwellings and so ApprovedDocument L2B applies to them
Dwellings within the scope of the
energy efficiency requirements
35 The energy efficiency requirements ofthe Building Regulations apply only to buildings
which are roofed constructions having walls andwhich use energy to condition the indoor climateFor dwellings the requirements will apply to
bull the erection of a dwelling (guidance on this isgiven in Approved Document L1A)
bull the extension of a dwelling other than someextensions falling within Class VII in Schedule2 to the Building Regulations or
bull the carrying out of any building work to or inconnection with an existing dwelling or anextension to an existing dwelling
Dwellings exempt from theenergy efficiency requirements
36 There are two exemptions from the energyefficiency requirements that may apply tobuilding work to existing dwellings or extensionsto existing dwellings
a Buildings which are
bull listed in accordance with section 1 ofthe Planning (Listed Buildings andConservation Areas) Act 1990
bull in a conservation area designated in
accordance with section 69 of that Act orbull included in the schedule of monuments
maintained under section 1 of the AncientMonuments and Archaeological Areas Act 1979
For these buildings the exemption appliesonly to the extent that compliance with theenergy efficiency requirements wouldunacceptably alter the character orappearance of such existing dwellingsGuidance on these buildings is given inparagraphs 37 to 314 below
b Carports covered yards covered ways andsome conservatories or porches attached toexisting dwellings Guidance on these isgiven at paragraphs 315 and 316 below
Historic and traditional buildings which mayhave an exemption
37 As mentioned above in paragraph 36a thefollowing classes of buildings have an exemptionfrom the energy efficiency requirements wherecompliance would unacceptably alter thecharacter or appearance of the buildings
a listed buildings
b buildings in conservation areas and
c scheduled ancient monuments
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GENERAL GUIDANCE L1B
9
Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
L I N E V E R I N
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L1B GENERAL GUIDANCE
10
Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
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Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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Approved Document L1B Conservation of fuel and power
GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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GUIDANCE RELATING TO BUILDING WORK L1B
15
Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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GENERAL GUIDANCE L1B
9
Approved Document L1B Conservation of fuel and power
Historic and traditional buildings wherespecial considerations may apply
38 There are three further classes of buildingswhere special considerations in making reasonableprovision for the conservation of fuel or powermay apply
a buildings which are of architectural and
historical interest and which are referred to asa material consideration in a local authorityrsquosdevelopment plan or local developmentframework
b buildings which are of architectural andhistorical interest within national parks areasof outstanding natural beauty registeredhistoric parks and gardens registeredbattlefields the curtilages of scheduledancient monuments and world heritage sites
c buildings of traditional construction withpermeable fabric that both absorbs andreadily allows the evaporation of moisture
39 When undertaking work on or inconnection with a building that falls within oneof the classes listed above the aim should be toimprove energy efficiency as far as is reasonablypracticable The work should not prejudice thecharacter of the host building or increase the riskof long-term deterioration of the building fabricor fittings
310 The guidance given by English Heritage3 should be taken into account in determiningappropriate energy performance standards forbuilding work in historic buildings
311 In general new extensions to historic ortraditional dwellings should comply with thestandards of energy efficiency as set out in this Approved Document The only exception wouldbe where there is a particular need to matchthe external appearance or character of theextension to that of the host building (seeparagraph 42)
312 Particular issues relating to work in historicbuildings that warrant sympathetic treatment andwhere advice from others could therefore bebeneficial include
a restoring the historic character of a buildingthat has been subject to previousinappropriate alteration eg replacementwindows doors and rooflights
b rebuilding a former historic building (egfollowing a fire or filling a gap site in a terrace)
c making provisions enabling the fabric of historicbuildings to lsquobreathersquo to control moisture andpotential long-term decay problems
313 In assessing reasonable provision forenergy efficiency improvements for historicbuildings of the sort described in paragraphs 37
and 38 it is important that the BCB takes intoaccount the advice of the local authorityrsquos
3 wwwenglish-heritageorguk
conservation officer The views of the conservationofficer are particularly important where buildingwork requires planning permission andor listedbuilding consent
314 Other classes of buildings to which specialconsiderations apply are usually non-domestic incharacter and so are covered in ADL2A and ADL2B
Conservatories and porches
315 Regulation 21 of the Building Regulationsexempts some conservatory and porch extensionsfrom the energy efficiency requirements Theexemption applies only for conservatories or porches
bull which are at ground level
bull where the floor area is less than 30 m2
bull where the existing walls doors and windowsin the part of the dwelling which separatesthe conservatory are retained or if removedreplaced by walls windows and doors whichmeet the energy efficiency requirements and
bull where the heating system of the dwelling isnot extended into the conservatory or porch
316 Where any conservatory or porch doesnot meet all the requirements in the precedingparagraph it is not exempt and must complywith the relevant energy efficiency requirements(see paragraphs 48 and 49 below)
Notification of work covered by
the Energy Efficiency requirements
317 In most instances in order to comply withthe Building Regulations it will be necessary tonotify a BCB before the work starts Where youchoose to use the local authority and any workrelates to the common parts of a block of flatsthis must be by deposit of full plans For otherexisting dwellings this could be either in the formof a deposit of full plans or by a building noticeThere is no set procedure where the BCB is an Approved Inspector provided they have beennotified at least 5 days before work starting
318 In certain situations however you do notneed to notify a BCB
a Where the work is being carried out by aperson registered with a relevant competentperson self-certification scheme listed inSchedule 3 to the Building Regulations noadvance notification to the BCB is needed(see paragraphs 319 to 322)
b Where the work involves an emergency repaireg to a failed boiler or a leaking hot watercylinder in accordance with regulation 12(7)of the Building Regulations there is no needto delay making the repair in order to makean advance notification to the BCB Howeverin such cases it will still be necessary for thework to comply with the relevant requirementsand to give a notice to the BCB at the earliestopportunity unless an installer registered under
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L1B GENERAL GUIDANCE
10
Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
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Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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Approved Document L1B Conservation of fuel and power
GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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GUIDANCE RELATING TO BUILDING WORK L1B
15
Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
N L I N E V E R I N
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
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B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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L1B GENERAL GUIDANCE
10
Conservation of fuel and power Approved Document L1B
an appropriate competent person schemecarries out the work A completion certificatecan then be issued in the normal way
c Where the work is of a minor nature asdescribed in the schedule of non-notifiablework (Schedule 4 to the Building Regulations)the work must still comply with the relevantrequirements but need not be notified to the BCB (see paragraphs 323 to 325)
Competent person self-certification schemes
319 It is not necessary to notify a BCB inadvance of work which is to be carried out bya person registered with a competent personself-certification scheme listed in Schedule 3 tothe Building Regulations In order to join such ascheme a person must demonstrate competenceto carry out the type of work the scheme coversand also the ability to comply with all relevantrequirements in the Building Regulations
320 Where work is carried out by a personregistered with a competent person schemeregulation 20 of the Building Regulations 2010and regulation 20(1) of the Building (ApprovedInspectors etc) Regulations 2010 require that theoccupier of the building be given within 30 days ofthe completion of the work a certificate confirmingthat the work complies fully with all applicablebuilding regulation requirements There is also arequirement to give the BCB a notice of the workcarried out again within 30 days of the completionof the work These certificates and notices areusually made available through the scheme operator
321 BCBs are authorised to accept thesecertificates and notices as evidence of compliancewith the requirements of the Building RegulationsLocal authority inspection and enforcementpowers remain unaffected although they arenormally used only in response to a complaintthat work does not comply
322 A list of authorised self-certification schemesand the types of work for which they are authorisedcan be found at wwwcommunitiesgovuk
Work which need not be notified
323 Schedule 4 to the Building Regulations
sets out types of work where there is no requirementto notify a BCB that work is to be carried outThese types of work are mainly of a minor naturewhere there is no significant risk to health safetyor energy efficiency Note that the health safetyand energy efficiency requirements continue toapply to these types of work and that only theneed to notify a BCB has been removed In additionwhere only non-notifiable work is carried out by amember of a competent person self-certificationscheme there is no requirement for a certificateof building regulations compliance to be given tothe occupier or the BCB
324 The types of non-notifiable work inSchedule 4 relevant to the energy efficiency requirements of the Regulations are
a In a heating hot water ventilation or air-
conditioning system the replacement of anypart which is not a combustion appliance(such as a radiator valve or pump) or theaddition of an output device (such as aradiator or fan) or the addition of a controldevice (such as a thermostatic radiator valve)However the work will remain notifiablewhenever commissioning is possible and
necessary to enable a reasonable use of fueland power (see paragraphs 430 to 437)
b The installation of a stand-alone self-contained fixed heating hot water ventilationor air-conditioning service Such servicesmust consist only of a single appliance andany associated controls and must not beconnected to or form part of any other fixed building service Examples of non-notifiableservices would be a fixed electric heater amechanical extractor fan in a kitchen orbathroom and a room air-conditioning unitHowever if any of the following apply the
work will remain notifiable building worki the service is a combustion appliance
ii any electrical work associated with theinstallation is notifiable
iii commissioning is possible and wouldaffect the servicersquos energy efficiency (seeparagraphs 430 to 438)
iv in the case of a ventilation appliance theappliance is installed in a room containinga natural draught open-flued combustionappliance or service such as a gas firewhich uses a chimney as its flue
c Installation of thermal insulation in a roofspace or loft space where this is the onlywork carried out and the work is not carriedout to comply with any requirement in theBuilding Regulations ie the work is carriedout voluntarily
325 Schedule 4 also sets out what typesof electrical installation work in dwellings arenon-notifiable Full information on this is givenin Approved Document P
Materials and workmanship
326 Any building work which is subject to therequirements imposed by Schedule 1 to theBuilding Regulations should in accordance withregulation 7 be carried out with proper materialsand in a workmanlike manner
327 You may show that you have compliedwith regulation 7 in a number of ways Theseinclude demonstrating the appropriate use of
bull a product bearing CE marking in accordancewith the Construction Products Directive(89106EC)4 as amended by the CE MarkingDirective (9368EC)5 the Low Voltage
4 As implemented by the Construction Products Regulations 1991
(SI 19911620)5 As implemented by the Construction Products (Amendment) Regulations
1994 (SI 19943051)
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GENERAL GUIDANCE L1B
11
Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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Conservation of fuel and power Approved Document L1B
L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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GENERAL GUIDANCE L1B
11
Approved Document L1B Conservation of fuel and power
Directive (200695EC)6 and the EMCDirective (2004108 EC)7
bull a product complying with an appropriatetechnical specification (as defined in thoseDirectives mentioned above) a BritishStandard or an alternative national technicalspecification of a Member State of theEuropean Union or Turkey 8 or of anotherState signatory to the Agreement on theEuropean Economic Area (EEA) that providesan equivalent level of safety and protection
bull a product covered by a national or Europeancertificate issued by a European Technical Approval Issuing body provided theconditions of use are in accordance with theterms of the certificate
328 You will find further guidance in the Approved Document which specifically supportsregulation 7 on materials and workmanship
Independent certification schemes329 There are many UK product certificationschemes Such schemes certify compliance withthe requirements of a recognised standard that isappropriate to the purpose for which the materialis to be used Materials which are not so certifiedmay still conform to a relevant standard
330 Many certification bodies that approveproducts under such schemes are accreditedby the United Kingdom Accreditation Service(UKAS) Such bodies can issue certificates onlyfor the categories of product covered under theterms of their accreditation
331 BCBs may take into account thecertification of products components materialsor structures under such schemes as evidence ofcompliance with the relevant standard Similarly BCBs may accept the certification of the installationor maintenance of products componentsmaterials or structures under such schemes asevidence of compliance with the relevant standardNonetheless before accepting that certificationconstitutes compliance with building regulationsa BCB should establish in advance that therelevant scheme is adequate for that purpose
Standards and technical specifications332 Building regulations are made for specificpurposes including securing the health safetywelfare and convenience of people in or aboutbuildings furthering the conservation of fuel andpower furthering the protection or enhancementof the environment and facilitating sustainabledevelopment Guidance contained in standardsand technical approvals referred to in ApprovedDocuments may be relevant to compliance withbuilding regulations to the extent that it relates tothose purposes However it should be noted that
6 As implemented by the Electrical Equipment (Safety) Regulations 1994
(SI 19943260)7 As implemented by the Electromagnetic Compatibility Regulations 2006
(SI 20063418)8 Decision No 195 of the ECndashTurkey Association Council of 22 December 1995
guidance in standards and technical approvalsmay also address other aspects of performancesuch as serviceability or aspects which althoughthey relate to health and safety are not coveredby building regulations
333 When an Approved Document makesreference to a named standard or document therelevant version of the standard or document isthe one listed at the end of the ApprovedDocument Until the reference in the ApprovedDocument is revised the standard or documentlisted remains the approved source but if theissuing body has published a revised or updatedversion any content that addresses the relevantrequirements of the Building Regulations may beused as a source of guidance
334 The appropriate use of a product thatcomplies with a European Technical Approval asdefined in the Construction Products Directivewill meet the relevant requirements
335 The Department for Communities andLocal Government intends to issue periodicamendments to its Approved Documents toreflect emerging harmonised Europeanstandards Where a national standard is to bereplaced by a European harmonised standardthere will be a coexistence period during whicheither standard may be referred to At the endof the coexistence period the national standardwill be withdrawn
The Workplace (Health Safety and
Welfare) Regulations 1992
336 The Workplace (Health Safety andWelfare) Regulations 1992 as amended apply tothe common parts of flats and similar buildings ifpeople such as cleaners wardens and caretakersare employed to work in these common partsThese Regulations contain some requirementswhich affect building design The main requirementsare now covered by the Building Regulationsbut for further information see Workplace health safety and welfare Workplace (Health Safety andWelfare) Regulations 1992 Approved Code ofPractice and guidance HSE publication L24 1996
337 Where the requirements of the BuildingRegulations that are covered by this ApprovedDocument do not apply to dwellings theprovisions may still be required in the situationsdescribed above in order to satisfy the WorkplaceRegulations
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Conservation of fuel and power Approved Document L1B
L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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Approved Document L1B Conservation of fuel and power
GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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L1B GUIDANCE RELATING TO BUILDING WORK
14
Conservation of fuel and power Approved Document L1B
Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
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RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Conservation of fuel and power Approved Document L1B
L1B
THE EXTENSION OF A DWELLING
Reference method
Fabric standards
41 Reasonable provision would be for theproposed extension to incorporate the following
a newly constructed thermal elements thatmeet the standards set out in paragraphs 51to 56
b doors windows roof windows and rooflightsthat meet the standards set out in paragraphs419 to 423
c improvements to fabric elements that are tobecome thermal elements following theguidance in paragraphs 56 to 511
Area of windows roof windows and doors42 In most circumstances reasonableprovision would be to limit the total area ofwindows roof windows and doors in extensionsso that it does not exceed the sum of
a 25 per cent of the floor area of the extensionplus
b the total area of any windows or doors whichas a result of the extension works no longerexist or are no longer exposed
As a general guide if the area of glazing is much less than 20 per cent of the total floor area some
parts of the extension and especially the part ofthe dwelling it covers may experience poor levelsof daylight resulting in increased use of electric lighting Areas of glazing greater than 25 per cent may be acceptable especially if this is required to make the extension consistent with the external appearance or character of the host buildingIn such cases and where practical either theU-value of the window should be improved relative to the standard set out in paragraph 41b or other compensating measures appliedfollowing the guidance set out in paragraphs 44 to 47
Heating and lighting in the extension
43 Where a fixed building service isprovided or extended as part of constructing theextension reasonable provision would be tofollow the guidance in paragraphs 426 to 437
Optional approaches with more
design flexibility
44 The approach set out in paragraphs 41to 43 is somewhat prescriptive The followingparagraphs offer more flexible approaches to
demonstrating that reasonable provision hasbeen made These alternative approaches allowsome elements of the design to be relaxedthrough compensating measures elsewhere
Area-weighted U-value method
45 One way of complying would be toshow that the area-weighted U-value of all theelements in the extension is no greater than thatof an extension of the same size and shape that
complies with the fabric standards referred to inparagraph 41 and the opening area standardsin paragraph 42 Any fixed building service provided or extended as part of constructingthe extension should follow the guidance inparagraphs 424 to 437
The area-weighted U-value is given by thefollowing expression
(U1 A 1 ) (U2 x A 2 ) (U3 x A 3 ) hellip)983092 (A 1 A 2 A 3 hellip)
Whole dwelling calculation method
46 Where even greater design flexibility isrequired reasonable provision would be to useSAP 2009 to show that the calculated carbondioxide (CO
2 ) emission rate from the dwelling
with its proposed extension is no greater than forthe dwelling plus a notional extension built to thestandards of paragraphs 41 to 43 The openingsin the notional extension should conform withparagraph 42 with door area set equal to thedoor area of the proposed extension with theremainder of the openings being classified aswindows The data in SAP 2009 Appendix Scan be used to estimate the performance of theelements of the existing building where these
are unknown
Approved Document C gives limiting values for individual elements to minimise condensation risk
47 If as part of achieving the standard set outin paragraph 46 upgrades are proposed to theexisting dwelling such upgrades should beimplemented to a standard that is no worse thanset out in the relevant guidance contained in this Approved Document The relevant standards forimproving retained thermal elements are as setout in column (b) of Table 3
Where it is proposed to upgrade the original
building the standards set out in this ApprovedDocument are cost-effective and should be implemented in full It will be worthwhile implementing them even if the improvement is greater than necessary to achieve complianceIn some cases therefore the standard of theextended dwelling may be better than that required by paragraph 46 alone Paragraph 47 sets limits on design flexibility and ensures that no cost-effective improvement opportunities aretraded away
Conservatories and porches
48 Where the extension is a conservatoryor porch that is not exempt from the energyefficiency requirements (see paragraphs 315
Section 4 Guidance relating to building work
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Approved Document L1B Conservation of fuel and power
GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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L1B GUIDANCE RELATING TO BUILDING WORK
14
Conservation of fuel and power Approved Document L1B
Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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GUIDANCE RELATING TO BUILDING WORK L1B
15
Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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L1B GUIDANCE RELATING TO BUILDING WORK
16
Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Approved Document L1B Conservation of fuel and power
GUIDANCE RELATING TO BUILDING WORK L1B
and 316 above) then reasonable provisionwould be to provide
a Effective thermal separation between theheated area in the existing dwelling iethe walls doors and windows betweenthe dwelling and the extension should beinsulated and draught proofed to at leastthe same extent as in the existing dwelling
b Independent temperature and onoff controlsto any heating system installed within theextension Any fixed building service installedwithin the extension should also conform to thestandards set out in paragraphs 424 to 437
c Glazed elements should meet the standardsset out in Table 1 and opaque elementsshould meet the standards set out in Table 2However the limitations on total area ofwindows roof windows and doors as setout at paragraph 42 above do not apply
49 Removing and not replacing any or all ofthe thermal separation between the dwelling andan existing exempt extension or extending thedwellingrsquos heating system into the extensionmeans the extension ceases to be exempt (seeparagraphs 315 and 316 above) This constitutesa change to the buildingrsquos energy status(Regulation 22) In such situations the extensionshould be treated as a conventional extensionand reasonable provision would be to demonstratethat the extension meets the guidance set out inparagraphs 41 to 47 above
Swimming pool basins
410 Where a swimming pool is being providedin a building the U-value of the basin (walls andfloor) should be not worse than 025 Wm2K ascalculated according to BS EN ISO 133709
MATERIAL CHANGE OF USE AND
CHANGE OF ENERGY STATUS
Material change of use
411 Material changes of use (see regulation 5of the Building Regulations) covered by thisdocument are where after the change
a the building is used as a dwelling wherepreviously it was not
b the building contains a flat where previouslyit did not or
c the building which contains at least onedwelling contains a greater or lesser numberof dwellings than it did previously
9 BS EN ISO 13370 Thermal performance of buildings Heat transfer via
the ground Calculation methods
Change of energy status
412 A change to a buildingrsquos energy status isdefined in regulation 2(1) as
any change which results in a building becominga building to which the energy efficiencyrequirements of these Regulations apply wherepreviously it was not
413 The requirements relating to a changeto energy status are in regulation 22
Where there is a change in a buildingrsquos energystatus such work if any shall be carried outto ensure that the building complies with theapplicable requirements of regulation 40 andPart L of Schedule 1
414 In this regulation lsquobuildingrsquo means thebuilding as a whole or parts of the building thathave been designed or altered to be usedseparately
For example this could occur where a previouslyunheated building or parts of the building that have been designed or altered to be used separately were to be heated in future or where a previously exempt building were no longerwithin the exempted categories A material alteration (regulation 3(2) and (3)) may result in a change in buildings energy status
415 In normal circumstances reasonableprovision where there is a material change ofuse or a change to the buildingrsquos energy statuswould be
a Where controlled services or fittings arebeing provided or extended to meet thestandards set out in paragraphs 417 to 437If the area of openings in the newly createddwelling is more than 25 per cent of the totalfloor area either the area of openings shouldbe reduced to be not greater than 25 per centor the larger area should be compensated forin some other way using the proceduredescribed in paragraph 416
b Where the work involves the provision of athermal element to meet the standards setout in paragraphs 51 to 56
For the purposes of Building Regulations provision means both new and replacement elements
c Where any thermal element is beingretained to upgrade it following the guidancegiven in paragraphs 511 to 513
d Where an existing window (including roofwindow or rooflight) or door which separatesa conditioned space from an unconditionedspace or the external environment has aU-value that is worse than 33 Wm2K toprovide replacement units following theguidance in paragraphs 419 to 423
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L1B GUIDANCE RELATING TO BUILDING WORK
14
Conservation of fuel and power Approved Document L1B
Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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L1B GUIDANCE RELATING TO BUILDING WORK
14
Conservation of fuel and power Approved Document L1B
Option providing more design
flexibility
416 To provide more design flexibility SAP2009 can be used to demonstrate that the totalCO
2 emissions from all the dwellings in the
building as it will become are no greater than ifeach dwelling had been improved following the
guidance set out in paragraph 415
WORK ON CONTROLLED
FITTINGS AND SERVICES
417 Controlled services or fittings aredefined in regulation 2 as follows
Controlled service or fitting means a service orfitting in relation to which Part G H J L or P ofSchedule 1 imposes a requirement
418 In the context of this Approved Documentthe application of the term controlled fitting to awindow roof window rooflight or door refers to awhole unit ie including the frame Consequentlyreplacing the glazing whilst retaining an existingframe is not providing a controlled fitting andso such work is not notifiable and does not haveto meet the Part L standards although wherepractical it would be sensible to do so Similararguments apply to a new door in an existing frame
Controlled fittings
419 Where windows roof windows rooflightsor doors are to be provided reasonable provision
in normal cases would be the installation ofdraught-proofed units whose performance is noworse than given in Table 1 In addition insulatedcavity closers should be installed where appropriateWhere the replacement windows are unable tomeet the requirements of Table 1 because of theneed to maintain the external appearance of thefaccedilade or the character of the building replacementwindows should meet a centre pane U-valueof 12Wm2K or single glazing should besupplemented with low-e secondary glazing Inthis latter case the weather stripping should be onthe secondary glazing to minimise condensationrisk between the primary and secondary glazing
420 U-values shall be calculated using themethods and conventions set out in BR 44310and should be based on the whole unit (ie in thecase of a window the combined performance ofthe glazing and frame) The U-value of thewindow can be calculated for
a the smaller of the two standard windowsdefined in BS EN 14351-111 or
b the standard window configuration set outin BR 443 or
c the specific size and configuration of theactual window
10 BR 443 Conventions for U-value calculations BRE 200611 EN 14351-1 Windows and doors ndash Product standard performance
characteristics 2006
SAP 2009 Table 6e gives values for differentwindow configurations that can be used in the absence of test data or calculated values
421 The U-values for roof windows androoflights given in this Approved Document arebased on the U-value having been assessedwith the roof window or rooflight in the verticalposition If a particular unit has been assessedin a plane other than the vertical the standardsgiven in this Approved Document should bemodified by making an adjustment that isdependent on the slope of the unit followingthe guidance in BR 443
Table 1 Standards for controlledfittings
Fitting Standard
Window roof window orrooflight
WER Band C or better (seeparagraph 422) or U-value
16 Wm2
KDoors with gt50 of internalface glazed
U-value = 18 Wm2K
Other doors U-value = 18 Wm2K
422 The Window Energy Rating (WER) is givenby the following equation
WER 1967 ((1 f) gglass ) ndash 685 (U (00165 AL))
Where f is the frame factor ie the percentage ofthe window obscured by frame and gaskets
gglass is the normal total solar energy transmittanceof the glass as determined by BS EN 410
U is the whole window U-value as specified inparagraph 420 and 421 and
AL is the air leakage through the window inm3 hm2 at 50 Pa pressure difference based ontesting to BS 6375ndash12009 Note that AL isbased on the whole window area not per unitlength of opening light
The following rating bands define the windowenergy rating label
Band A WER
0Band B 0 WER ndash10
Band C ndash10 WER ndash20
Band D ndash20 WER ndash30
Band E ndash30 WER ndash50
Band F ndash50 WER ndash70
Band G ndash70 WER
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GUIDANCE RELATING TO BUILDING WORK L1B
15
Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
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L1B GUIDANCE RELATING TO BUILDING WORK
16
Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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GUIDANCE RELATING TO BUILDING WORK L1B
15
Approved Document L1B Conservation of fuel and power
BCBs may accept a WER declaration from acertification scheme that provides a quality-assuredprocess and supporting audit trail from calculatingthe performance of the window through to installationas evidence of compliance Notwithstanding thesuggested performance values set out aboveguidance on energy-efficient windows isavailable from the Energy Saving Trust12
423 If a window is enlarged or a new onecreated then the area of windows roof windowsrooflights and doors should not exceed 25 percent of the total floor area of the dwelling unlesscompensating measures are included elsewherein the work
Controlled services
424 Whenever a fixed building service isextended or provided reasonable provisionwould be demonstrated by following theguidance set out in the Domestic BuildingServices Compliance Guide13 The Guide coversthe following services
a heating and hot water systems (includinginsulation of pipes ducts and vessels
b mechanical ventilation
c mechanical coolingair-conditioning
d fixed internal lighting
e fixed external lighting
f renewable energy systems
425 The efficiency claimed for the fixed building service should be based on the appropriate teststandard as set out in the Domestic BuildingServices Compliance Guide and the test datashould be certified by a notified body It would bereasonable for BCBs to accept such data at facevalue In the absence of such quality-assureddata BCBs should satisfy themselves that theclaimed performance is justified
426 When replacing an existing appliancethe efficiency of the new appliance should notbe significantly less than the efficiency of theappliance being replaced If the replacementinvolves a fuel switch then the relative carbonemissions associated with the new and existingfuels should be considered when assessing thereasonableness of the proposed new applianceThe Domestic Building Services Compliance Guidecontains the detailed guidance on this issue
427 If a renewable energy generator suchas a wind turbine or photovoltaic array is beingreplaced the new system should have anelectrical output that is not less than theoriginal installation
12 httpwwwenergysavingtrustorgukHome-improvements-and-
productsHome-insulation-glazingGlazing13 Domestic Building Services Compliance Guide DCLG 2010 edition
428 When replacing a heating applianceconsideration should be given to connectingto any existing local heat networks If the workinvolves pipework changes consideration shouldbe given to providing capped off connections tofacilitate subsequent connection to a plannedlocal heat network
429 If a particular technology is not coveredin the Domestic Building Services ComplianceGuide reasonable provision would be demonstratedby showing that the proposed technology givesa performance that is no worse than a referencesystem of the same type whose details are givenin the Guide
COMMISSIONING OF FIXED
BUILDING SERVICES
430 Paragraph L1(b)(iii) of Schedule 1 to theBuilding Regulations requires fixed building services to be commissioned by testing andadjustment as necessary to ensure that they useno more fuel and power than is reasonable in thecircumstances In order to demonstrate that theheating and hot water systems have beenadequately commissioned regulation 44 states
44 Commissioning
(1) This regulation applies to building work inrelation to which paragraph F1(2) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed system formechanical ventilation or any associated controlswhere testing and adjustment is not possible
(2) This regulation applies to building work inrelation to which paragraph L1(b) of Schedule 1imposes a requirement but does not apply tothe provision or extension of any fixed buildingservice where testing and adjustment is notpossible or would not affect the energy efficiencyof that fixed building service
(3) Where this regulation applies the personcarrying out the work shall for the purpose ofensuring compliance with paragraph F1(2) orL1(b) of Schedule 1 give to the local authority anotice confirming that the fixed building services
have been commissioned in accordance with aprocedure approved by the Secretary of State
(4) The notice shall be given to the local authorityndash
a not later than the date on which the noticerequired by regulation 16(4) is required to begiven or
b where that regulation does not apply not morethan 30 days after completion of the work
I N
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L1B GUIDANCE RELATING TO BUILDING WORK
16
Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
N
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
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B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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L1B GUIDANCE RELATING TO BUILDING WORK
16
Conservation of fuel and power Approved Document L1B
431 Reasonable provision would be to preparea commissioning plan identifying the systemsthat need to be tested and the tests that will becarried out The notice required by regulation20C should confirm that the commissioning planhas been followed and that every system hasbeen inspected in an appropriate sequence andto a reasonable standard and that the test results
confirm that performance is reasonably inaccordance with the design requirements
432 Not all fixed building services will need tobe commissioned With some systems adjustmentis not possible as the only controls are lsquoonrsquo andlsquooffrsquo switches Examples of this would be somemechanical extraction systems or single fixedelectrical heaters In other cases commissioning would be possible but in the specific circumstanceswould have no effect on energy use
Fixed building services which do not requirecommissioning should be identified in thecommissioning plan along with the reasonfor not requiring commissioning
433 Where commissioning is carried out itmust be done in accordance with a procedureapproved by the Secretary of State For heatingand hot water systems the approved proceduresare set out in the Domestic Building ServicesCompliance Guide For ventilation systemsan approved procedure would be to followthe guidance in the Domestic VentilationCompliance Guide14
434 Commissioning is often carried out by theperson who installs the system In other cases it
may be carried out by a subcontractor or by aspecialist firm It is important that whoever carriesit out follows the relevant approved procedure indoing so
435 Where a building notice or full plans havebeen given to a local authority BCB the notice ofcompletion of commissioning should be given tothat BCB within 5 days of the completion of thecommissioning work In other cases for examplewhere work is carried out by a person registeredwith a competent person scheme (see paragraphs319 to 322) it must be given within 30 days
14 Domestic Ventilation Compliance Guide DCLG 2010
436 Where an approved inspector is the BCBthe notice of completion of commissioning should generally be given to the approvedinspector within 5 days of the completion ofwork However where the work is carried outby a person registered with a competent personscheme (see paragraph 319 to 322) the noticemust be given within 30 days Where the
installation of fixed building services whichrequire commissioning is carried out by aperson registered with a competent personscheme the notice of commissioning will begiven by that person
437 Until the BCB receives the commissioningnotice it cannot be reasonably satisfied that Part Lhas been complied with and consequently isunlikely to be able to give a completionfinalcertificate
N
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
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RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
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RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
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B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Approved Document L1B Conservation of fuel and power
L1B
51 New thermal elements must comply withPart L1(a)(i) of Schedule 1 to the BuildingRegulations Work on existing thermal elements must comply with regulation 23 of the BuildingRegulations which states
23ndash(1) Where a person intends to renovate athermal element such work shall be carried outas is necessary to ensure that the whole thermalelement complies with the requirements ofparagraph L1(a)(i) of Schedule 1
(2) Where a thermal element is replaced the newthermal element shall comply with the requirementsof paragraph L1(a)(i) of Schedule 1
THE PROVISION OF THERMAL
ELEMENTS
U-values52 U-values shall be calculated using themethods and conventions set out in BR 443
53 Reasonable provision for newly constructedthermal elements such as those constructedas part of an extension would be to meet thestandards set out in Table 2
54 Reasonable provision for those thermalelements constructed as replacements forexisting elements would be to meet the standardsset out in Table 2
Table 2 Standards for new thermalelements
Element1 Standard (Wm2K)2
Wall 028
Pitched roof ndash insulation at ceiling level 016
Pitched roof ndash insulation at rafter level 018
Flat roof or roof with integral insulation 018
Floors3 0224
Swimming pool basin 025
Notes
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquoincludes the wall parts (cheeks) of dormer windows
2 Area-weighted average values
3 A lesser provision may be appropriate where meeting such astandard would result in a reduction of more than 5 in theinternal floor area of the room bounded by the wall
4 A lesser provision may be appropriate where meeting such a standardwould create significant problems in relation to adjoining floor levelsThe U-value of the floor of an extension can be calculated using theexposed perimeter and floor area of the whole enlarged dwelling
Continuity of insulation and
airtightness
55 The building fabric should be constructedso that there are no reasonably avoidable thermal
bridges in the insulation layers caused by gapswithin the various elements at the joints betweenelements and at the edges of elements suchas those around window and door openingsReasonable provision should also be made toreduce unwanted air leakage through the newenvelope parts The work should comply with allthe requirements of Schedule 1 but particularattention should be paid to Parts F and J
56 A suitable approach to showing therequirement has been achieved would be toadopt Accredited Construction Details atwwwplanningportalgovuk
It is impractical to expect thermal bridge andtemperature factor calculations for work inexisting buildings
RENOVATION OF THERMAL
ELEMENTS
57 For the purposes of this Approved Document renovation of a thermal element through
a the provision of a new layer means either ofthe following activities
i Cladding or rendering the external surface
of the thermal element or
ii Dry-lining the internal surface of athermal element
b the replacement of an existing layer meanseither of the following activities
i Stripping down the element to expose thebasic structural components (brick blockwork timbermetal frame joistsrafters etc) and then rebuilding toachieve all the necessary performancerequirements As discussed in paragraph39 particular considerations apply to
renovating elements of traditionalconstruction or
ii Replacing the water proof membrane ona flat roof
58 Where a thermal element is subject to a renovation through undertaking an activity listedin paragraph 57a or 57b the performance of thewhole element should be improved to achieveor better the relevant U-value set out in column(b) of Table 3 provided the area to be renovatedis greater than 50 per cent of the surface of theindividual element or 25 per cent of the total
building envelope When assessing this areaproportion the area of the element should betaken as that of the individual element not all theelements of that type in the building The area of
Section 5 Guidance on thermal elements
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
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RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Conservation of fuel and power Approved Document L1B
L1B GUIDANCE ON THERMAL ELEMENTS
the element should also be interpreted in thecontext of whether the element is beingrenovated from inside or outside eg if removingall the plaster finish from the inside of a solidbrick wall the area of the element is the area ofexternal wall in the room If removing externalrender it is the area of the elevation in which thatwall sits
This means that if all the roofing on the flat roof of an extension is being stripped down the area ofthe element is the roof area of the extension notthe total roof area of the dwelling Similarly if the rear wall of a single-storey extension was being re-rendered it should be upgraded to the standardsof Table 3 column (b) even if it was less than50 per cent of the total area of the buildingelevation when viewed from the rear If plaster is being removed from a bedroom wall the relevant area is the area of the external wall in the room not the area of the external elevation whichcontains that wall section This is because the
marginal cost of dry-lining with insulated plasterboard rather than plain plasterboard is small
59 If achievement of the relevant U-value setout in column (b) of Table 3 is not technically orfunctionally feasible or would not achieve a simple payback of 15 years or less the elementshould be upgraded to the best standard that istechnically and functionally feasible and whichcan be achieved within a simple payback of nogreater than 15 years Guidance on this approachis given in Appendix A
510 When renovating thermal elements thework should comply with all the requirements inSchedule 1 but particular attention should bepaid to Parts F and J
RETAINED THERMAL ELEMENTS
511 Part L of Schedule 1 to the BuildingRegulations applies to retained thermalelements in the following circumstances
a where an existing thermal element is part ofa building subject to a material change of use
b where an existing element is to become part ofthe thermal envelope where previously it wasnot eg as part of a loft or garage conversionwhere the space is now to be heated
512 Reasonable provision would be to upgradethose thermal elements whose U-value is worsethan the threshold value in column (a) of Table 3to achieve the U-values given in column (b) ofTable 3 provided this is technically functionallyand economically feasible A reasonable test ofeconomic feasibility is to achieve a simple payback of 15 years or less Where the standardgiven in column (b) is not technically functionally
or economically feasible then the thermalelement should be upgraded to the beststandard that is technically and functionallyfeasible and delivers a simple payback period of15 years or less Generally this lesser standardshould not be worse than 07 Wm2K
Examples of where lesser provision than column(b) might apply are where the thickness of the additional insulation might reduce usable floor area of any room by more than 5 per cent orcreate difficulties with adjoining floor levels orwhere the weight of the additional insulation might not be supported by the existing structural
frame513 When upgrading retained thermalelements the work should comply with allthe requirements in Schedule 1 but particularattention should be paid to Parts F and J
Table 3 Upgrading retained thermal elements
Element1 (a) Threshold U-value Wm2middotK 8 (b) Improved U-value Wm2middotK 8
Wall ndash cavity insulation2 070 055
Wall ndash external or internal insulation3 070 030
Floor45 070 025
Pitched roof ndash insulation at ceiling level 035 016
Pitched roof ndash insulation between rafters6 035 018
Flat roof or roof with integral insulation7 035 018
1 lsquoRoofrsquo includes the roof parts of dormer windows and lsquowallrsquo includes the wall parts (cheeks) of dormer windows
2 This applies only in the case of a wall suitable for the installation of cavity insulation Where this is not the case it should be treated as lsquowall ndash external orinternal insulationrsquo
3 A lesser provision may be appropriate where meeting such a standard would result in a reduction of more than 5 in the internal floor area of the roombounded by the wall
4 The U-value of the floor of an extension can be calculated using the exposed perimeter and floor area of the whole enlarged building
5 A lesser provision may be appropriate where meeting such a standard would create significant problems in relation to adjoining floor levels
6 A lesser provision may be appropriate where meeting such a standard would create limitations on head room In such cases the depth of the insulationplus any required air gap should be at least to the depth of the rafters and the thermal performance of the chosen insulant should be such as to achievethe best practicable U-value
7 A lesser provision may be appropriate if there are particular problems associated with the load-bearing capacity of the frame or the upstand height
8 Area-weighted average values
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Approved Document L1B Conservation of fuel and power
L1B
61 Regulation 28 of the Building Regulationsmay require additional work to be undertaken tomake an existing building more energy efficient
when certain types of building work are proposed62 This requirement arises in existing buildingswith a total useful floor area of over 1000 m2 where the proposed work consists of
a an extension
b the initial provision of any fixed building service (other than a renewable energygenerator)
c an increase to the installed capacity of anyfixed building service (other than arenewable energy generator)
63 Consequential improvements shouldonly be carried out to the extent that they aretechnically functionally and economically feasible
64 Only a relatively small number of existingdwellings will exceed 1000 m2 in size Where thereis doubt the BCB can be consulted for advice
65 Technical guidance on achieving compliancewith regulation 28 is not given in this ApprovedDocument but where the regulation applies it isavailable in Approved Document L2B
Section 6 Consequential improvements toenergy performance
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
N L I N E V E R I N
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APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
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Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
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Conservation of fuel and power Approved Document L1B
L1B
71 On completion of the work in accordancewith regulation 40 the owner of the dwelling should be provided with sufficient informationabout the building the fixed building services and their operating and maintenancerequirements so that the dwelling can be operatedin such a manner as to use no more fuel andpower than is reasonable in the circumstancesThis requirement applies only to the work thathas actually been carried out eg if the workinvolves replacing windows there is no obligationon the contractor to provide details on theoperation of the heating system
72 Where the work involves the provision of anew heating system a way of complying wouldbe to provide a suitable set of operating andmaintenance instructions aimed at achievingeconomy in the use of fuel and power in termsthat householders can understand in a durableformat that can be kept and referred to over theservice life of the system(s) The instructionsshould be directly related to the particularsystem(s) installed as part of the work that hasbeen carried out
73 Without prejudice to the need to complywith health and safety requirements anyinstructions should explain to the occupier of thedwelling how to operate the system(s) efficientlyThis should include
a the making of adjustments to timingtemperature and flow control settings
b what routine maintenance is needed toenable operating efficiency to be maintainedat a reasonable level through the servicelive(s) of the system(s)
Section 7 Providing information
N L I N E V E R I N
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
N L I N E V E R I N
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
E R I N
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 263124
Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
N L I N E V E R I N
N L I N E V E R I N
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3031
APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
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Approved Document L1B Conservation of fuel and power
L1B
Appendix A Work to thermal elements
1 Where work involves the renovation of athermal element an opportunity exists forcost-effective insulation improvements to beundertaken at marginal additional cost Thisappendix provides guidance on the cost-effectiveness of insulation measures whenundertaking various types of work on athermal element
2 Table A1 sets out the circumstances and thelevel of performance that would be consideredreasonable provision in ordinary circumstancesWhen dealing with existing dwellings someflexibility in the application of standards is necessaryto ensure that the context of each scheme canbe taken into account while securing as far aspossible the reasonable improvement The finalcolumn in Table A1 provides guidance on anumber of specific issues that may need to beconsidered in determining an appropriate courseof action As part of this flexible approach it willbe necessary to take into account technical riskand practicality in relation to the dwelling underconsideration and the possible impacts on anyadjoining building In general the proposed worksshould take account of
a the requirements of any other relevant partsof Schedule 1 to the Building Regulations
b the general guidance on technical risk relatingto insulation improvements contained inBR 26215
c for buildings falling within the categories setout in paragraphs 37 to 38 the guidanceproduced by English Heritage
Where it is not reasonable in the context of theworks project to achieve the performance set outin Table A1 the level of performance achievedshould be as close to this as practically possible
3 Table A1 incorporates in outline form examplesof construction that would achieve the proposedperformance but designers are free to use anyappropriate construction that satisfies the energyperformance standard so long as they do notcompromise performance with respect to any
other part of the Building Regulations4 General guidance is available from suchsources as the Energy Saving Trust and relevantBritish Standards
15 BR 262 Thermal insulation Avoiding risks BRE 2002
N L I N E V E R I N
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Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
E R I N
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WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
N L I N E V E R I N
8112019 Part L_Regs
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Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
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Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
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Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
N L I N E V E R I N
N L I N E V E R I N
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Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3031
APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 243122
Conservation of fuel and power Approved Document L1B
L1B WORK TO THERMAL ELEMENTS
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Pitched roof constructions16
Renewal of roof covering ndash No
living accommodation in the roofvoid ndash existing insulation (if any) atceiling level No existing insulationexisting insulation less than50 mm in poor condition andor likely to be significantlydisturbed or removed as partof the planned work
016 Provide loft insulation ndash
250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fill orequivalent
Assess condensation risk in roof space and
make appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide accessto and insulation of services in the roof void
Renewal of roof covering ndash Existinginsulation in good condition andwill not be significantly disturbedby proposed works Existinginsulation thickness 50 mm or morebut less than 100 mm
016 Top up loft insulation to atleast 250 mm mineral fibreor cellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in line with therequirements of Part C relating to the controlof condensation Additional provision maybe required to provide insulation and accessto services in the roof void
Where the loft is already boarded out and
the boarding is not to be removed as part ofthe work the practicality of insulation workswould need to be considered
Renewal of the ceiling to cold loftspace Existing insulation at ceilinglevel removed as part of the works
016 Provide loft insulation ndash250 mm mineral fibre orcellulose fibre as quiltlaid between and acrossceiling joists or loose fillor equivalent This may beboarded out
Assess condensation risk in roof space andmake appropriate provision in accordancewith the requirements of Part C relatingto the control of condensation Additionalprovision may be required to provide insulationand access to services in the roof void
Where the loft is already boarded out andthe boarding is not to be removed as partof the work insulation can be installed fromthe underside but the target U-value maynot be achievable
Renewal of roof covering ndashLiving accommodation in roofspace (room-in- the-roof typearrangement) with or withoutdormer windows
018 Cold structure ndash Insulation(thickness dependent onmaterial) placed betweenand below rafters
Warm structure ndash Insulationplaced between and aboverafters
Assess condensation risk (particularlyinterstitial condensation) and makeappropriate provision in accordance withthe requirements of Part C relating to thecontrol of condensation (Clause 84 ofBS 52502002 and BS EN ISO 137882002
Practical considerations with respect to anincrease in structural thickness (particularlyin terraced dwellings) may necessitate alower performance target
Dormer window constructions
Renewal of cladding to side walls 030 Insulation (thicknessdependent on material)placed between andor
fixed to outside of wallstuds Or fully externalto existing structuredepending on construction
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
Renewal of roof covering ndash Follow guidance onimprovement to pitched orflat roofs as appropriate
Assess condensation risk and makeappropriate provision in accordance with therequirements of Part C
E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 2531
WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 263124
Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 273125
Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 283126
Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 293127
Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3031
APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 2531
WORK TO THERMAL ELEMENTS L1B
23
Approved Document L1B Conservation of fuel and power
16 Specification of thickness of insulation is based on lambda values (conductivity) of 004 WmK
Table A1 Cost-effective U-value targets when undertaking renovation works to
thermal elements
Proposed works Target U-value(Wm2K)
Typical construction Comments (reasonablenesspracticability and cost- effectiveness)
Flat roof constructions
Renewal of roof covering ndash Existing
insulation if any less than 100mm mineral fibre (or equivalentresistance) or in poor conditionand likely to be significantlydisturbed or removed as partof the planned work
018 Insulation placed between
and over joists as requiredto achieve the targetU-value ndash Warm structure
Assess condensation risk and make
appropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Renewal of the ceiling to flat roofarea Existing insulation removedas part of the works
018 Insulation placed betweenand to underside of joiststo achieve target U-value
Assess condensation risk and makeappropriate provision in accordance withthe requirements of Part C Also see BS62292003 for design guidance
Where ceiling height would be adverselyaffected a lower performance target may beappropriate
Solid wall constructions
Renewal of internal finish toexternal wall or applying a finish forthe first time
030 Dry-lining to inner face ofwall ndash insulation betweenstuds fixed to wall toachieve target U-value ndashthickness dependenton insulation and studmaterial used
Insulated wall board fixedto internal wall surfaceto achieve the requiredU-value ndash thicknessdependent on materialused
Assess the impact on internal floor area Ingeneral it would be reasonable to accept areduction of no more than 5 in the areaof a room However the use of the roomand the space requirements for movementand arrangements of fixtures fittings andfurniture should be assessed
In situations where acoustic attenuationissues are particularly important (egwhere insulation is returned at party walls)a less demanding U-value may be moreappropriate In such cases the U-valuetarget may have to be increased to 035 orabove depending on the circumstances
Assess condensation and other moisturerisks and make appropriate provision inaccordance with the requirements of PartC This will usually require the provision ofa vapour control and damp protection tocomponents Guidance on the risks involvedis provided in BR 262 and on the technicaloptions in Energy Saving Trust publications
Renewal of finish or cladding toexternal wall area or elevation(render or other cladding) orapplying a finish or cladding for thefirst time
030 External insulation systemwith rendered finish orcladding to give requiredU-value
Assess technical risk and impact ofincreased wall thickness on adjoiningbuildings
Ground floor constructions
Renovation of a solid or suspendedfloor involving the replacement ofscreed or a timber floor deck
See comment Solid floor ndash replace screedwith an insulated floor deckto maintain existing floorlevel
Suspended timber floor ndashfit insulation between floor joists prior to replacementof floor deck
The cost-effectiveness of floor insulation iscomplicated by the impact of the size andshape of the floor (perimeterarea ratio)In many cases existing un-insulated floorU-values are already relatively low whencompared with wall and roof U-valuesWhere the existing floor U-value is greaterthan 070 Wm2K then the addition ofinsulation is likely to be cost-effective Analysis shows that the costndashbenefit curvefor the thickness of added insulation is veryflat and so a target U-value of 025 Wm2Kis appropriate subject to other technicalconstraints (adjoining floor levels etc)
V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 263124
Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 273125
Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 283126
Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 293127
Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3031
APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 263124
Conservation of fuel and power Approved Document L1B
L1B
BRE
wwwbrecouk
BR 262 Thermal insulation avoiding risks 2001ISBN 978 186081 515 7
BRE Report BR 443 Conventions for U-valuecalculations 2006 (Available at wwwbrecouk uvalues)
Department for Business
Innovation and Skills
wwwbisgovuk
Technical Standards and Regulations Directive9834EC (Available at wwwbisgovukpolicies innovationinfrastructureStandardisationtech-standards-directive)
Department for Energy andClimate Change (DECC)
wwwdeccgovuk
The Governmentrsquos Standard AssessmentProcedure for energy rating of dwellings SAP2009 (Available at wwwbrecouksap2009)
Current Energy Prices (wwwdeccgovuken contentcmsstatisticspublicationspricespricesaspx)
Department for Communities and
Local Government (DCLG)wwwcommunitiesgovuk
Accredited Construction Details for Part L (Available to download fromwwwplanningportalgovukengland professionalsen1115314255826html)
Energy Saving Trust (EST)
wwwestorguk
Energy Efficient Glazing ndash guidance(Available at wwwenergysavingtrustorguk
Home-improvements-and-productsHome-insulation-glazingGlazing)
English Heritage
wwwenglish-heritageorguk
Building Regulations and Historic Buildings 2002(revised 2004) and other guidance
Health and Safety Executive (HSE)
wwwhsegovuk
L24 Workplace Health Safety and Welfare
Workplace (Health Safety and Welfare)Regulations1992 Approved Code of Practiceand Guidance The Health and SafetyCommission 1992 ISBN 978 0 71760 413 5
NBS (on behalf of the Department
for Communities and Local
Government)
wwwthebuildingregscom
Domestic Building Services Compliance GuideDCLG 2010
Domestic Ventilation Compliance GuideDCLG 2010
(Both available to download from wwwplanningportalgovuk)
Legislation
Ancient Monuments and Archaeological Areas Act 1979
Listed Buildings and Conservation Areas) Act 1990
SI 19911620 Construction ProductsRegulations 1991
SI 19943051 Construction Products (Amendment)Regulations 1994
SI 19943260 Electrical Equipment (Safety)Regulations 1994
SI 20002214 The Building Regulations 2010
SI 20002215 The Building (Approved Inspectorsetc) Regulations 2010
SI 20063418 Electromagnetic Compatibility
Regulations 2006Decision No 195 of the EC-Turkey AssociationCouncil of 22 December 1995
Appendix B Documents referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 273125
Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 283126
Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 293127
Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3031
APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 273125
Approved Document L1B Conservation of fuel and power
L1B
BS EN ISO 133702007 Thermal performance ofbuildings Heat transfer via the groundCalculation methods
BS EN 14351-12006 Windows and doors
Product standard performance characteristicsWindows and external pedestrian doorsetswithout resistance to fire andor smoke leakagecharacteristics
BS EN 4101998 Glass in building Determinationof luminous and solar characteristics of glazing
BS 6375-12009 Performance of windowsand doors Classification for weathertightnessand guidance on selection and specification
BS 52502002 Code of practice for controlof condensation in buildings
BS EN ISO 137882002 Hygrothermal
performance of building components andbuilding elements
BS 62292003 Flat roofs with continuouslysupported coverings Code of practice
Appendix C Standards referred to
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 283126
Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 293127
Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3031
APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 283126
Conservation of fuel and power Approved Document L1B
L1B
Index
A
Accredited construction detailsschemes 56
Airtightness 55 Ancient monuments 36 37 Approved Document L1B
Conventions 19Purpose 11ndash16Types of work covered 32ndash34
Architectural interest 38 Area-weighted U-value 45
B
BCBSee Building Control Body (BCB)
British Standards Appendix CBR 262 2002 Appendix A BS EN 14351 2006 420BS EN ISO 13370 410
Building Control Body (BCB)Definition 31
Notice of completion ofcommissioning 435ndash437Notification of work 317ndash318
Building fabricStandards 41See also Thermal elements
Building log book 72ndash73Building Regulations 21ndash24
Appendix BBuilding services
See Fixed building services
C
Cavity walls Table 3CE marking 327Certification
Competent person self-certificationschemes 319ndash322
Product certification schemes329ndash331
Change of energy status 412ndash415Change of use 411 415Cladding 57Commissioning
Definition 31Fixed building services 430ndash437
Common areas 336Competent person self-certification
schemes 319ndash322Compliance with requirements
12ndash13 111Materials and workmanship 327
331Self-certification 321
Consequential improvements 21 3161ndash65
Conservation areas 36 37Conservatories 315ndash316 48ndash49Controlled fittings 417ndash423 Table 1
Definition 31Controlled services 422 424ndash429
Definition 31
D
DERSee Dwelling CO
2 Emission Rate
(DER)Design flexibility 44ndash47 416Doors Table 1 42 48 415 419
Dormer windows Table A1Dry lining 57Dwelling
Definition 31Dwelling CO
2 Emission Rate (DER)
46ndash47
E
Emergency repairs 318Energy efficiency requirements 21
Compliance with 12ndash13 111Definition 31Exemptions 36Fixed building services 425ndash426
Energy performance
Consequential improvements 3161ndash65See also Dwelling CO
2 Emission Rate
(DER)Energy Performance Certificate
21ndash24Energy status change 412ndash415European standards 335European Technical Approval 327
334Exemptions 36Extensions 35 41ndash410
Consequential improvements 62Historic or traditional dwelling 311
F
FabricSee Building fabric
Fixed building services 424ndash427Commissioning 430ndash437Consequential improvements 62Definition 31Replacement 426System efficiencies 425ndash426See also Controlled services Heating
and hot water systems LightingFlat roofs 57 58 Table A1Floors
Upgrades Table 3U-values Table 2 Table A1
GGlazing
See Windows
H
Health and safety 336ndash337Heating and hot water systems
Commissioning 430ndash437Controls 48Extensions 43Non-notifiable work 324See also Fixed building services
Historic buildings 36ndash313
I
Independent certification schemes 329ndash331
Information provision 71ndash73Insulation
See Thermal insulation
Internal lighting 43
L
Legislation Appendix BEuropean 327See also Building Regulations
Lighting 43Limitation on requirements 22ndash24Listed buildings 36 37Low and zero carbon (LZC)
technologies 427 429
M
Maintenance instructions 72ndash73
Material change of use 411 415Materials and workmanship 326ndash328Minor works 323ndash325Mixed-use buildings 34Multiple dwellings 411
N
National parks 38Non-notifiable work 323ndash325Notice of completion of
commissioning 435ndash437Notification of work 317ndash318
O
Operating and maintenanceinstructions 72ndash73
P
Payback period 59 512Porches 315ndash316Product certification schemes
329ndash331Publications (excluding BSI and
European Standards) Appendix BConstruction Products Regulations
1991 (SI 19911620) 327Conventions for U-value calculations
(BR 443 2006) 420Domestic Building Services
Compliance Guide (DCLG 2010)424Domestic Ventilation Compliance
Guide (DCLG 2010) 433Electrical Equipment (Safety)
Regulations 1994 (SI 19943260)327
Electromagnetic CompatibilityRegulations 2006 (SI 20063418)327
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 293127
Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3031
APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 293127
Approved Document L1B Conservation of fuel and power
INDEX L1B
R
Rendering 57 58Renewable energy systems 427Renovation 33 47
Definition 31Historic and traditional buildings 312Thermal elements 51 57ndash510
Appendix A Table A1Replacement
Appliances 426ndash428Thermal elements 51 58Windows 419 423
Replacement windows 415Replastering 58Rooflights Table 1 421Roofs
Renovation 57 58Upgrades Table 3U-values Table 2 Table A1
Roof windows 42 48 415 419 421Table 1
Room for residential purposesDefinition 31
S
SAP 2009 46Self-certification schemes 319ndash322Simple payback 59 512
Definition 31Standard Assessment Procedure
(SAP 2009) 46Standards 332ndash335
See also British StandardsSwimming pools Table 2 410
T
Technical specifications 332ndash335Thermal bridges 55ndash56Thermal elements 51ndash513
Definition 31Renovation 57ndash510 Appendix A
Table A1Replacement 51 58Retained 511ndash513Upgrades 59 512ndash513 Table 3U-values 52ndash54
Thermal insulation 324 55ndash56 Appendix A
Thermal separation 48 49Traditional construction 38
U
Upgrades 47Thermal elements 59 512ndash513
Table 3
U-values 415 51 Table 2 Area-weighted 45Controlled fittings 419ndash423 Table 1Renovation targets Table A1
W
WallsUpgrades Table 3U-values Table 2 Table A1
Whole dwelling calculation method 46ndash47
Window Energy Rating (WER) 422Windows
Area of glazing 42
Conservatories and porches 48Replacement 415U-values 419ndash423 Table 1
Workmanship 326ndash328Workplace (Health Safety and
Welfare) Regulations 1992 336ndash337
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3031
APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3031
APPROVED DOCUMENTSThe following documents have been approvedand issued by the First Secretary of State for thepurpose of providing practical guidance withrespect to the requirements of the BuildingRegulations 2010
Approved Document A Structure
2004 edition incorporating 2010 amendments Approved Document B (Fire safety) ndash Volume1 Dwellinghouses2006 edition incorporating 2010 amendments
Approved Document B (Fire safety) ndash Volume2 Buildings other than dwellinghouses2006 edition incorporating 2007 and 2010amendments
Approved Document C Site preparation andresistance to contaminants and moisture2004 edition incorporating 2010 amendments
Approved Document D Toxic substances1992 edition incorporating 2002 and 2010amendments
Approved Document E Resistance to thepassage of sound2003 edition incorporating 2004 and 2010amendments
Approved Document F Ventilation2010 edition incorporating further 2010 amendments
Approved Document G Sanitation hot watersafety and water efficiency2010 edition incorporating further 2010 amendments
Approved Document H Drainage and wastedisposal2002 edition incorporating 2010 amendments
Approved Document J Combustionappliances and fuel storage systems2010 edition incorporating further 2010 amendments
Approved Document K Protection from falling
collision and impact1998 edition incorporating 2000 and 2010amendments
Approved Document L1A Conservation offuel and power ndash New dwellings2010 edition incorporating further 2010 amendments
Approved Document L1B Conservation offuel and power ndash Existing dwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document L2A Conservation offuel and power ndash New buildings other than
dwellings2010 edition incorporating further 2010 amendments
Approved Document L2B Conservation offuel and power ndash Existing buildings other thandwellings2010 edition incorporating further 2010 and 2011amendments
Approved Document M Access to and use ofbuildings2004 edition incorporating 2010 amendments
Approved Document N Glazing ndash safety inrelation to impact opening and cleaning
1998 edition incorporating 2000 and 2010amendments
Approved Document P Electrical safety ndashDwellings2006 edition incorporating 2010 amendments
Approved Document to support regulation 7Materials and workmanship1999 edition incorporating 2010 amendments
N L I N E V E R I N
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
8112019 Part L_Regs
httpslidepdfcomreaderfullpart-lregs 3131
Published by NBS part of RIBA Enterprises Ltd and available from
RIBA Bookshops Mail Order
15 Bonhill Street
London EC2P 2EA
Telephone ordersGeneral enquiries 020 7256 7222
Fax orders 020 7374 2737
Email orders salesribabookshopscom
Or order online at
wwwthenbscombuildingregs
RIBA Bookshops
RIBA 66 Portland Place London WIB 1AD Telephone 020 7256 7222
Birmingham amp Midland Institute Margaret Street Birmingham B3 3SP Telephone 0121 233 2321
RSUA 2 Mount Charles Belfast BT7 1NZ Telephone 02890 323 760
CUBE 113-115 Portland Street Manchester M1 6DW Telephone 0161 236 7691
milkandsugar 82 Wood Street Liverpool L1 4DQ Telephone 0151 707 4380
ISBN 978 1 85946 325 3
Stock code 72233
copy Crown Copyright 2010
Reprint December 2010 with corrections
Copyright in the typographical arrangement rests with the Crown
This publication excluding logos may be reproduced free of charge in any formator medium for research private study or for internal circulation within anorganisation This is subject to it being reproduced accurately and not used in amisleading context The material must be acknowledged as Crown copyright andthe title of the publication specified This documentpublication is value addedIf you wish to re-use please apply for a Click-Use Licence for value addedmaterial at wwwopsigovukclick-usesystemonlinepLoginasp or by writing tothe Office of Public Sector Information Information Policy Team Kew RichmondSurrey TW9 4DU Email licensingopsigovuk If you require this publication inan alternative format please email alternativeformatscommunitiesgsigovuk
wwwthenbscom
B ui l d i n g
R e g ul at i o
n s 2 0 1 0
A P P R OV E D
D O C UME NT L 1 B
C o
n s er v a t i on of f u el an d p ow
er
N L I N E V E R I N
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