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The combination of wood and stone gives charm to a typical

farmhouse.

Key dates The farm dates back to before 1900.Beginning of the plans : 2006 Planning permission secured : 2010. Works : 2011 to 2012.

In order to preserve the stone farmhouse they inherited from their parents, Anne and Michel wished to renovate it. They have given it a second life by creating 5 holiday lets. To give the holiday units a more contemporary look, they wanted to marry ancient materials taken from the site with 21st century ones, without losing the essence of the location. The Eco-friendliness of the dwellings is shown through the use of recyclable or reused materials (stones, beams, doors) as well as natural heating and sanitation systems.

Introduction

Saint Brieuc

Quimper

Vannes

Rennes

Baden

Les Eco-Logis

Overview - Photo © Servane Guihaire - Constructys Bretagne

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ContextThe owners crated a limited company (SARL) called Les Eco Logis de Lairmarc’h, enabling them to offer visitors welcoming, easy to heat and eco-friendly holiday lets.The project is in a fairly popular tourist area: Le Golfe du Morbihan, between the sea and countryside. The buildings are south facing. The T – shape enables 3 of the lets to be south facing while the other 2 are west-facing.The proximity of the coast means that the Local Plan Area is restrictive, and the only possible change of use for the building was to holiday accommodation and the only contractor accepted was a farmer.

These holiday dwellings, covering an area of 370 sq m (3980 sqft) are attached to, and in close proximity, to the farm; privacy was therefore a requirement put forward by the architect. Therefore, the layout was also influenced by the desire to keep cars away to make the site wheelchair friendly. One of the lets is especially converted for disabled people, as laid out in the regulation for disabled access (law of 11/02/2005).

Plan © A’Dao

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French-British collective Libnam3

Building overview Two different systems were used for the renovation ; the existing buildings are in stone while the extension is timber-framed.The stone buildings are on shallow existing foundations. The internal solid wall was insulated by blowing 15 cm of cellulose fibre and covered by gypsum boards (Fermacell). Where there was a higher risk of damp, walls have been insulated with cork.The timber frame is made of pinewood beams (45x145 mm) and laid on a concrete slab, which is insulated underneath by sheets of polyurethane 10 cm thick (Sporema brand). The wall insulation is made of cellulose fibre, applied between timber posts, and covered by

chipboard to assure continuity of the outer-shell.The distribution of the internal layout is made of steel frame and plasterboard (BA13) or gypsum boards (Fermacell), using wood wool as an insulator.The window and door frames were tailor-made by MC France. They are made of wood and steel, and double glazed. They do not come with rolling blinds as they would look inappropriate on listed buildings and would create thermal bridges.The holiday lets are all equipped with a wood burner with different capacity depending on the area to heat. Electrical heating can be used when necessary. However, in order to promote the use of renewable energy, the wood is provided for free while electricity is charged on top of the rental price.

Framing - Photo © Yann Denion - CICS

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The ventilation is a Hygro B type (outlet and inlet air hygro adjustable).

A 10 m3 water tank was installed to recover rainwater for watering, toilets and washing machines (situated in the communal laundry at the entrance). The water sewage treatment is done by phyto-purification ponds. Structure of the roof, from outside in : slates - battens - cellulose fibre - vapour barrier - gypsum boards (Fermacell).

Structure of the stone walls : Stone - Whitewash - rain barrier - Douglas fir frame - 15 cm thick cellulose fibre - vapour barrier - gypsum boards (Fermacell).

Structure of the partition walls : 22 mm Douglas fir cladding - battens (thermal gap) - Wood fibre boards (6 cm Pavatex) - Rain barrier - Bracing pannels (18 cm OSBracing) - 15 cm insulated frame - Vapour barrier - Gypsum boards (Fermacell).

Timber-framed extension - Photo © Servane Guihaire - Constructys Bretagne

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Technical focus : Stone and insulationCellulose fibre (made of recycled newspapers) is commonly used as insulation for timber frame buildings, but more rarely for stone buildings. The cellulose fibre used on site (by Isocel) is produced by a company called Celaouate in Morlaix, from recycled local papers such as Le Télégramme, which ensures a low carbon footprint due to its local production.As well as cellulose fibre’s insulating quality, it has greater thermal mass than mineral wool. This makes it a useful product to reduce the temperature difference inside the building, in particular during heat waves. Married with stone, cellulose fibre provides comfort in the summer time, and the holiday

lets are used mainly during warm months.

Here, the cellulose fibre was blown into the wooden frame and sealed by a vapour barrier. The device blows the cellulose fibre through an opening in the vapour barrier which is then tightly sealed. Moisture must not reach the insulation. This requires careful implementation in respect of the stone, such as pointing the outside walls and the protection of the lower parts. For example, rain barriers have been applied at the bottom of walls and loose cork was put in the areas most exposed to capillary rise.It is important to note that borax is integrated into cellulose fibre. This mineral has fire retardant properties and enables protection from fungus and rodents. In 2012 and 2013, in France, the public health safety of this additive caused controversy. For

Interior - Photo © Servane Guihaire - Constructys Bretagne

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Barriers and solutionsOn a legal and regulatory level, several problems were encountered. For example, the site is situated in a conservation area, so it was necessary to communicate with Architecte des Batiments de France (French equivalent of English

Heritage), especially for the creation of West-facing openings and the modification of the facade.To put the phytopurification (water treatement using a reed bed) in place, it was necessary to explain to the Syndicat Intercommunal d’Alimentation en Eau Potable (Local water board) what the system was about. The constant evolution of the techniques can bring misunderstandings from regulation bodies which can slow down eco-construction. This is one of the reasons why companies have to keep training to obtain certificates as well as skills.For the cellulose fibre, the company CICS underwent training with different organisations: Domus

a while, building regulations used ammonium salts, but finally chose to reinstate the use of borax; and for good reasons since ammonium may degrade into ammonia and this has potential health risks, whereas borax has been judged to have a low impact, below a 5% threshold.The cellulose fibre industry has however decided to start research work to identify substitute to these salts.

Bedroom - Photo © Servane Guihaire - Constructys Bretagne

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(supplier), Tyeco2, Ecolusis and ARFAB (airtight). They also attended training in Energy-saving in the building industry. Monitoring by the main contractor on site, discussions with the architect, and regular site reports allowed better communication between the trades, even if it did not avoid all the problems. For instance, there was a large turnover of employees in one company which complicated the passing down of some instructions. However, to reach the target thermal performance, each contractor had to pay attention to the work of others.There are many technical constraints

that guided the homeowners’ choices : lime and hemp concrete is interesting in terms of insulation but would have resulted in walls that were too thick ; a heat-recovery device would have been complicated to install for 5 independent cottages ; solar panels would have resulted in a lot of wiring and trouble during a possible division of dwellings in the future.Finally, a few technical problems occurred on the building site : creating weep holes on the cement-rendered stone walls was very complicated, the gypsum boards were heavy and difficult to cut, and the concrete slab took time to dry in winter as the building was well insulated.

Inside - Photo © Servane Guihaire - Constructys Bretagne

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StakeholdersMain contractor : SARL Les Eco Logis de Lairmarc’h (Baden)Architect : A’Dao (Rennes)Project manager : Gérard Lucas (Les Fougerêts) Masonry : Pelbois (Pluherlin)Carpentry-Joinery : Burban (Malansac)Insulation – internal walls : CICS (Saint Nicolas du Tertre)Services : SARL Coué Crété (St Martin/Oust) Plumbing : Lubert (Limerzel)Electricity : Cornec Pac Elec (Plougoumelen)Tiling : Roux SARL (Guegon) Stairs : Potier JP (Rieux) Decorating : Le Tournel Sarl (La Gacilly) Wood burners : Nicolas Cheminées (Lanester) Landscaping and sewage : Aubat (Landaul) Phytopurification Conception : Aquatiris (Landevant)

Linkwww.lafermh-baden.fr

Costs Project management : 8.6% of the global of the build : £41,167 before taxGroundwork and connection to services : £27,526 before taxMasonry and structural work : £85,315 before taxFrame : £58,189 before taxRoofing and waterproofing : £40,644 before taxIndoors and outdoors joinery : £54,875 before taxElectricity and heating : £35,967 before taxInternal walls and insulation : £71,730Plumbing : £25,918 before taxTiling : £27,430 before taxStairs : £9,152 before taxDecorating : £25,901 before tax Total : £503,814 before tax, equivalent to £1,361 per sq m

A partial thermal survey was done during the study phase in order to choose the correct materials. The building did not aim to achieve any specific eco-labels, the wish being to make a more energy-efficient

PerformancePerspective © A’Dao

building with environmentally friendly materials.Following readings, it was found that eight people consume twelve euros worth of hot water and electricity per week (about 90 kWh).

ContactConstructys Bretagnewww.constructys-bretagne.fr