Caps et Marais d’Opale Regional Nature Park ACCOMPANIED SELF-RENOVATION

FEEDBACK FROM 2019 SITE LE WAST

North façade of the house.

What is Auto-Réhabilitation Accompagnée (accompanied self-renovation - ARA)? ARA is an assistance tool enabling owners to renovate their own home or building in accordance with industry standards, with the support of a professional trained to supervise the work. This arrangement concerns the inhabitants of Caps et Marais d’Opale Regional Nature Park (Park), with priority given to owners of homes of historic value constructed prior to 1948, who wish to renovate their house using environmentally friendly materials. The aim is to make the home more energy efficient, while preserving the architectural characteristics which contribute to the identity of the local area. In order to ensure people take advantage of this arrangement, the project is partly participatory. A team of volunteers, keen to learn some renovation techniques, comes to give a hand. For a few hours, the site becomes a place for interaction, learning and fun. This sheet shows an example of the work conducted as part of the accompanied self-renovation of a detached house built prior to 1948.

Site description Techniques and materials

Loft insulation of a detached house through injection

n ARA work? Reinforcement of rafters, n Date of construction? Before 1948. Reinforcement of the insulation under the roof slopes as well roof structure used as n Area? 15m² of gable, 104m² of roof as on the east gable of the loft using chambers (i.e. 52m²/roof slope). injected cellulose wadding, installation of an airtight membrane. n Project duration? Around 2 weeks, with 7 days of ARA support. n Where? in Le Wast. Insulation under the n Who is involved? Institut des Mines et Télécom (IMT) of Lille-Douai roof slopes as well as (Mohammed-Hichem Benzaama, Lala on the east gable of Rajaoarisoa and a team of students); the loft using injected Sylvain Huret, coordinating architect cellulose wadding of the renovation work and guide. and installation of an airtight membrane. ACCOMPANIED SELF-RENOVATION

An essential step: the overall project review Work executed under an ARA The owner’s view Work executed outside an It is essential to plan the project as far in advance as possible. The Park had «Thermal and acoustic quality has several conversations with the owner to determine its needs, deadlines and mo- ARA 3 days of assistance for 4 days of assistance for insulation been secured. I no longer hear tivations. the installation of rafter and airtightness Work was carried out directly by the street noise and my heating only reinforcements owner or external agents: comes on very cold days.» A comprehensive assessment of the house is then conducted to identify any The insulation was installed by the = Removal of glass wool in the flaws in the dwelling and thus adapt the work. The owner and guide constructed mechanical injection of cellulose unused loft space, rafter reinforcements which also form wadding packaged in bulk, with a = Change of windows on the ground This project, part of a European Before the project began, Sylvain Huret, the coordinating architect of the chambers to receive the cellulose thickness of 25cm under the roof floor, programme called SHINE, bene- renovation work, met the owner to discuss an issue in the roof structure. wadding through injection. Around slope (giving a thermal resistance = Installation of a double-glazed fited from a thermal analysis car- The investigations conducted enabled a study of the technical and finan- 1/4 of the rafters were damaged or of R = 6m²K/W) and 15cm against window (east façade gable), ried out free of charge by the IMT cial feasibility of the loft insulation work. incorrectly aligned (i.e. 15 axes). the gable (R = 3.7m²K/W). Humidity = Installation of a roof subframe to (Institut des Mines et Télécom) of In order to address this, the rafter and airtightness are managed by the provide light. Lille-Douai, highlighting points of During the work, the project guide showed how to execute some of the reinforcements were attached to installation of a variable membrane. the shell that require monitoring, most delicate work (reinforcement of the roof structure, construction of the existing rafters using wooden using sensors installed prior to chambers to receive the injection of cellulose wadding, installation of battens (class 2 treated softwood, Thus, in winter, the vapour-barrier the work. Other sensors will be the insulation by injection, finishings) correctly and in accordance with in 36X63mm sections) to enable the membrane prevents humidity from installed after the work, which will industry standards. installation of OSB panels (9mm in getting into the loft. In summer, it make it possible to observe im- thickness). ensures drying towards the interior. provements in terms of the ther- Excess humidity evaporates throu- mal performance of the house ghout the year, preventing any risk (see supplement: “The SHINE of mildew. European programme in Les Caps et Marais d’Opale Regio- nal Nature Park”). Installation of a double-glazed window in the gable

Difficulties encountered by the owner “A part of the roof structure of Details of rafter reinforcements. the house has serious structural Instrumentation phase through the installation of sensors (heat, humidity and light) before the energy efficiency work. problems and prioritising the energy work to carry out was complicated. Using an ARA site helped me get expert advice from a professional builder.” ARA budget The question of responsibilities For the work: When the project has been properly The guide’s 7 days of technical support from a craftsman €3,323, inc. VAT defined before the start of the work, the various parties sign an agreement. This view 80% borne by Les Caps et Marais d’Opale includes: = a commitments contract which «The owner of the house had just Regional Nature Park (€2,658, inc. VAT) establishes the missions and had an unpleasant experience obligations of each party, Cost of materials €6,000, inc. VAT = with a company. Thanks to the a site contract which specifies the ARA arrangement, it was possible Borne by the owner. work to execute according to the ARA arrangement, the schedule and the to establish a relationship of trust Total of €6,664, inc. VAT, to be borne by the owner. post-project maintenance advice, with professional builders. In = a specific article on the insurance addition to considerable energy policies that should be taken out. and financial savings, the project This is a guarantee of the correct enabled human interactions execution of the various phases of the Picture after insulation work under the roof slope. You will notice that the holes made for that were valuable for everyone injection have been filled in to ensure perfect airtightness. involved.» ACCOMPANIED SELF-RENOVATION

Focus on .... Insulation of roof slopes with cellulose wadding The cellulose wadding is made of 100% recycled material (obtained from paper and newspapers). In addition to the thermal insulation of the buildings (thermal resistance of 7m²K/W on a thickness of 273mm, density of 47kg/m3), cellulose wadding also has excellent acoustic properties. Cellulose wadding as thermal insulation may be installed in 3 ways: blowing into unused roof space, injection into a sloped roof and injection into walls. The method described here is injection into a sloped roof.

=Materials: 2. Laying of the vapour barrier for injection - Cellulose wadding. 600kg of cellulose wadding are needed for Once the chambers have been completed, the vapour barrier is insulation of a thickness of 273mm over 100m², variable vapour-barrier installed on the inner side (heated volume). To do this, the vapour membrane, installation accessories (adhesive and sealing glue) barrier is rolled out and stapled to the intermediate purlins and boards. - Wood for chambers (rafters, OSB-type wooden panels), As soon as the vapour barrier has been installed, airtightness is =Equipment: injection machine, masks, gloves, goggles, ensured by attaching the strips of vapour barrier to each other, as measuring tools, cutting tools (saw, cutter), well as the side gables and walls, using the glues and adhesives =Time: 1 day to inject the wadding over an area of brought specifically for this purpose. 104m² by 2 people, =Cost: Cellulose wadding (1.13/kg), variable vapour-barrier 3. Battening and injection membrane (2.82/m² inc. VAT), adhesive tape for attaching In order to ensure that the vapour barrier does not swell too much overlapping strips (21.02 inc. VAT), double-sided adhesive tape under pressure during injection, battens must be fixed to the to attach joints to edges of underlays (6.34 inc. VAT), sealing intermediate purlins and boards, perpendicular to the chambers. glue for attaching to rough or mineral construction components Then, simply inject the cellulose wadding into the chambers, with (6.76 inc. VAT). a density of 47 to 55kg/m3. This will prevent the insulation from settling over time. 1. Preparation of chambers Chambers, between 45 and 60cm in width, are constructed as a support with the roof underlay and intermediate purlins. There are more attachment points (stapling, counter-battens) than usual to ensure that the vapour-barrier membrane is firmly fixed in place. May 2019. Photo credits: Les Caps et Marais d’Opale Regional Nature Park Example of an operator injecting cellulose wadding under the roof slope. Source: www.biofib.com. Park Resources = Technical guide: “Energy audits in traditional buildings”, more information 2013 = Technical guide: “Green renovation in Les Caps et Marais = Lucie Duterte, green renovation project manager d’Opale: How can we insulate and protect older +33 (0)3 21 87 86 26 or [email protected] homes?”, 2014 = ARA project feedback sheet, 2016 = ARA Réty project feedback sheet, 2016 = ARA project feedback sheet, 2017 Park Offices: = ARA Conteville-lès-Boulogne project feedback sheet, 2018 > Manoir du Huisbois, Le Wast = ARA Le Wast project feedback sheet, 2019 > Maison du Marais, Saint-Martin-lez-Tatinghem = ARA project feedback sheet, 2019 postal address: BP 22, 62142 LE WAST Download at https://www.parc-opale.fr/patrimoines/bati/ara Tel. +33 (0)3 21 87 90 90 [email protected] 1.2 Le positionnement « Une autre vie s’invente ici » The financiers: www.parc-opale.frla typographie Facebook: Parc Opale Une autre vie s’invente ici

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Parcs naturels régionaux de Charte d’utilisation du logotype – septembre 2013 – 15