BBC Effinergie: wood frame house in Lozere

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Le wooden lounge Forum Marvejols BBC has a wooden house in Lozere

The first BBC-certified wooden house in Lozère called "the most watertight house in France" (BBC: Bâtiment Basse Consommation)

In February 2010, the company ORLHAC sarl built the first wooden house in Lozere labeled BBC (House Lagloire to Montrodat) according to the plans of architect Nathalie Crepin. The results of the blower door test (Q4 = 0,07) for the labeling of the building, have a much better performance than necessary to label BBC (Q4 = 0,60) and even to those of the label LIABILITIES (Q4 = 0,20).

The tests passed hands down, this wooden house was qualified as "the most watertight house in France ..." by SIRTEME, certifier organization. The Grenelle 2 law, published in the official gazette on 13 July 2010, aims to improve energy efficiency in buildings and harmonize planning tools.

In view of this publication, this construction built in February was very avant-garde because of the new regulations and test scores.

Questions to Jean-Pierre Orlhac, manufacturer and Nathalie Crépin, architect

CCI: Can you clarify what a BBC home?

JPO: It is a low energy house. The designation BBC Effinergie is an energy performance label constructions. It refers to new buildings whose very low energy requirements (for heating, hot water, ventilation, ...) can significantly reduce fuel consumption and thus the cost of running the house, but also its gas emissions Greenhouse effect.

NC: A BBC home has every interest to meet the criteria of a bioclimatic building to take full advantage of environmental inputs before calling technology (solar photovoltaic, solar thermal, heating system ...). Bioclimatism allows use from the design of a house, the advantages of the microclimate of the implantation site (sunshine, prevailing winds, soil inertia ...) without neglecting the human side of the project, that is -dire functionality and comfort. A bioclimatic house must strive for energy independence through a symbiosis with the natural environment.

CCI: What are the difficulties in the implementation of this type of work? and what a blower door test?

JPO: To achieve an efficient and economical home from an energy point of view, healthy and comfortable for its occupants and at an acceptable cost, it is necessary to adopt a comprehensive approach from the design of the house.

It will in particular ensure the compactness of the house, its orientation, the level of insulation of walls and woodwork, the airtightness at the choice of ventilation and heating system.

Obtaining the BBC Effinergie Label requires a very high level of insulation, but it also incorporates an imperative parameter control of the airtightness of the walls. This is to eradicate parasites cold air intakes, which may represent 25% of heat loss of traditional buildings (cold air entered by decision, on the perimeter of the openings through the roof ...).
The aim of the infiltrometry test is to measure these parasitic air leaks and penetrations. For this purpose, a "blower door" and pressure sensors are connected to a computer for controlling the measurements. The building is pressurized and depressed to simulate the effect of wind on the exterior walls and measure the rate of air exchange by leaks. This test was carried out during construction (self-checking phase) and at the end of the construction site to check that the house meets the requirements of the BBC-Effinergie label.

The results of the infiltrometry test are excellent (9 times better than the requirements of the BBC label, 3 times better than the label PASSIVE HOUSE) and confirm the performance of the low energy wood wall "ORLHAC" developed by our office internal study, manufactured and implemented by the ORLHAC carpenter team.

ICC: What are the challenges in the design of this type of project?

NC: The labeling of a BBC building is obtained after tests and mainly thermal and energy studies. The difficulty in designing this type of building is that thermal requirements should not take precedence over all the parameters related to the project design: functionality, integration to the site, comfort of life, and costs ... The draft Mr. and Mrs. Lagloire is as such a success because no concession aesthetic and functional (eg accessibility) was made at the expense of its thermal performance.

CCI: Is the wood a particularly suitable material for designing houses BBC?

JPO: That's exactly right. timber construction, well designed and well controlled, is well positioned to meet the thermal performance requirements and control construction costs. Wood is also a natural, renewable and clean, which has a beneficial effect on the potential for global warming: it can store a large amount of carbon; between 20 and 30 tons for a detached house.

NC: The benefits of designing a BBC house wood frame are multiple. This offers more freedom for the integration of windows or bioclimatic greenhouses. The timber also facilitates the junctions between the vertical walls, the horizontal walls and openings. The building gains in coherence and thereby the thermal bridges and air are reduced. Thanks to prefabrication of timber frame, the on-site assembly of duration is fast and risk approximation diminished.

CCI: A common idea is that wooden buildings have a lower life expectancy than "traditional" buildings (concrete, bricks, stone, etc.). What do you think ?

JPO: There are no particular problems on the durability of wood constructions. There are numerous examples in France and abroad. Here, one of the oldest houses in Saint Chely d'Apcher, home of Miss BONNET, is a timbered house with wooden support structure ... Of course, as with all construction materials, wood requires a good design and know-how of implementation.

NC: This misconception is understandable, here in Lozère, because historically the building material was stone. In areas (eg Alsace) or countries (eg Sweden) in which the buildings were constructed of wood, this preconceived idea does not exist. We find buildings with centuries-built timber (forerunner of the wooden frame), or adobe houses.

CCI: Do you think it is possible and profitable to design buildings BBC to higher dimensions (semi-apartment buildings, kindergartens, schools, ...)?

JPO: Of course. The search for thermal performance, control of operating and heating costs, occupant well-being and respect for the environment is also present in collective buildings. The large BBC buildings appear here and there: social housing, schools, crèches, administrative buildings. In 2009, we took part in the construction of a "passive" administrative building of 350 m2: although it is located in an unfavorable climate zone, this building does not require a traditional heating system or air conditioning.

NC: As the building is large easier it is to design the BBC because the more you can make the compact building, the more decreases the surface of the outer walls and thus the sources of losses. Today I work for example in the design of a timber housing in Ispagnac, which is common to several families. The association of the buildings there allows a reduction in energy costs.

CCI: What is the future of the wooden house and the BBC in Lozere?

JPO: Environmental issues, energy management and regulatory developments lead us to prefer low energy consumption buildings. To achieve this, the wood will remain a reliable, comfortable, economical and respectful of our environment.

NC: After this experience, I direct all my sites to test the seal because it provides a guarantee to the quality of implementation. More companies are likely to experience the BBC over this implementation mindful of detail will become obvious.

Moreover, the Lozère is the department with the lowest average temperature, the heating-related energy expenditure is important, the return on investment is very fast. This should logically be very incentive for developing BBC Lozère.

Questions to Mr. and Mrs. Lagloire, project promoters

ICC: Why and how did you get the urge to build this type of home?

SL: Initially, we did not know the concept of the BBC, we wanted a bioclimatic house and integrated into our build environment (semi urban Caussenard atmosphere). So we appealed to Nathalie CREPIN was sensitized bioclimatism. She designed the house on these principles plus an accessibility constraint for a person in a wheelchair. On this basis, we filed a building permit on February 6 2010 and obtained two months later. At this point, we still do not have a notion of the BBC.

Later, during a discussion with Mathieu COUDERC, in charge of the Department of renewable energy, we discovered the BBC and its financial benefits (energy savings and tax benefits).

Soon, we sought information and local artisans to adapt our project with BBC requirements. We met with the company ORLHAC who worked on wooden houses with high energy performance. The seriousness and motivation of this business we decided to embark on the adventure of the BBC. So we gathered all the companies with which we planned to work and we presented them our project and BBC as no craftsman had no experience in this area, we asked them if they agreed to play the game and they all accepted. We wish also to thank again because they were great in the quality of their work.

ICC: Why wood? Is it easy to carry a wooden house project in Lozere?

SL: My parents have a wood frame house came directly from Germany for thirty years and it is built, it is still comfortable and reasonably consuming energy. Looking at the design of this house, we saw that the Germans were well ahead in wood construction.

CCI: How long took place from the project idea to the layout in your house?

SL: The idea of ​​the strict consensus BBC project emerged the 13 2009 April when we met with Mathieu Couderc (the permit was already obtained), and we moved the 26 August.

CCI: Is there an extra cost in this project compared to a so-called "classic" house? Is it compensated and how?

SL: Basically, we had a house with an original design (greenhouse arched), specific equipment (Canadian well, comfort ventilation, solar thermal, solar photovoltaic, breezes sun), we used still little used materials by artisans (wood wool, fermacell, tiles larch) which increases the cost compared to a conventional actual construction, but it was a personal choice.

The cost of the house is estimated at 1 600 € TTC / m2.

With experience, we have learned that we can still make the BBC a more modest cost. We believe the BBC, it is mostly a reflection (often common sense) on the orientation of the house, insulation, choice of materials and electrical equipment (including ventilation) and most of all excellent quality of implementation on tightness parasite air and on the latter point, the company ORLHAC brilliantly showed that she was very competent.

- Wood forum salon Marvejols
- Visit eco-habitat forum, BBC and HQE ...
- Discussion of the labels and standards of ecological and economical housing


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