Build an ecological house: what materials to choose?

Construct and furnish his house with the help of natural materials, it is possible. Here is our selection of eco-friendly products.

construction materials

Construction and building materials

Save energy and preserve their health

Today, the industrialised countries spend approximately 80% of their time inside a room, office or housing. Yet, few architects or contractors are concerned about health problems related to habitat.

To save energy, the housing has become increasingly tight, thus promoting the development of micro-organisms, vectors, asthma and other respiratory illnesses. Opt for a green building, it is first of all respect the health of the occupants and make the choice of natural materials adapted to bio-climatic conditions of the location (amount of sunlight, prevailing winds, rain water, ground water, etc.).

Build with natural materials

To limit the harvesting of natural resources, during the construction of dwellings, houses or apartments can be made using materials of renewable origin, such as wood, hemp, straw, mud or bricks monomur...

The wood

In France, only a single house out of the fifteen is built with wood, compared to one in two in Japan and nine in ten in Scandinavia. "The number of wooden buildings increases by 15 % every year, finds Hervé Boivin, Abibois, the association interprofessionnelle du bois in Brittany. It is a recyclable material, renewable (provided they are from well managed forests), which stores CO2 during its growth, and the guard a prisoner when the tree is cut. In addition, it is fifteen times more insulating than concrete."

Qualities that explain his return to grace, in particular, to construct the skeleton of the buildings that we can then "fill in" with other eco-friendly materials, such as bricks made of hemp or straw bales for example.

The hemp

Plant environmentally friendly, it grows easily, even in a poor land, requires little fertilizer, little water and no pesticides. Mixed with lime, its fibers are a concrete placed between boards, formwork, branches. Once the concrete of hemp dry, they are removed and it protects the wall at the inside and the outside using a coating (about 500 €/m2). The implementation of this material requires to follow certain rules. For the neophytes, manufacturers offer bricks of hemp prefab can be used without particular qualification (approximately 30 €/m2).

The straw

The idea of building a house of straw that reminds you of a little too the story of the three little pigs ? Don't worry, in France, the oldest building of straw, built at Montargis in 1921, is still standing and in perfect condition ! The principle : one builds a wood frame that is then filled with bales of straw before the coat of lime to protect the walls of the fire (approximately 1 to 2 € the bunch).

The thickness of the material provides excellent insulation capacity comparable to that of a wall of cinder block-lined 24 cm of rock wool. The construction of straw meeting a lot of success among home builders, but few professionals have mastered (60 to 2 000 €/m2). In addition, the straw being regarded in France as an insulator, the manufacturer, therefore, can not allow his client to benefit from the ten-year warranty as usual.

The raw earth

Like straw, the mud is a material that is recyclable, renewable, non-polluting and available locally. You can mount it between two branches or use bricks made from a mixture of earth and lime spent in a press and left to dry for several weeks (about 60 €/m2). In both cases, it is necessary to protect the house from inclement weather with "boots" and a "hat", that is to say, a stone base, or brick, and advanced to roof.

The bricks monomur

For those who prefer a more traditional materials, bricks monomur are a good compromise. These brick and tile are very thick (30 to 50 cm) are covered by alveoli. The air they contain and their high thermal inertia to isolate the building. A great resistance, they permit the construction of multi-storey and the masons professionals are adapting to it easily (about 50 €/m2 for a thickness of 30 cm). Very popular, these bricks are unfortunately not the most ecological material that is : cooking (several hours at 1 000 °C in ovens to gas) requires a lot of energy grey !

Insulation material, high performance

Some green building materials, such as straw and the brick monowall, also serve as insulation. But if the walls of your home are made of cinder block or land, there are insulating performance identical to those of the mineral wools without their disadvantages health. Which one to choose ?

"It depends on the climate, the altitude and the orientation of the house," explains Alain Drouilleau, the manager of the Store of nature, which sells eco-friendly materials since 1996 (www.eco-logis.com). And of the implementation. Do we want to isolate it from the inside or the outside ? For rigid insulation, which also serves as of inner wall or is it scheduled ?"

Cellulose wadding and cork

The insulating environmentally friendly the most used in Europe is the cotton cellulose, which is composed of waste paper or sludge from paper mill. It has the same insulating power than wool, mineral, but its production requires much less energy : 6 kWh, compared to 150 kWh (rock wool) 250 kWh (glass wool), according to Ademe. It is found in bulk, to instill in containers, or panels (17-19 €/m2 for 10 cm thickness).

Its closest competitor, cork, brings together all the qualities : lightweight, rot-proof, water-repellent, non-flammable, impervious to fungus and insects. It offers a thermal performance comparable to those of cotton cellulose, but its price is higher (30 €/m2). "These are the two most high-performance materials for sound insulation," said Alain Drouilleau.

Hemp and flax

Hemp is also an effective solution and easy to implement, as it is presented in the form of panels or flexible rolls of different thicknesses, which does not mandate the intervention of a professional (from 13 to 16 €/m2). Like hemp, flax is grown easily and does not require inputs of pollutants. The fibers are processed into insulating panels which absorb moisture well, which is why we have used them for a long time in Northern Europe (from 15 to 17 €/m2).

Sheep wool

Insulating unexpected, sheep wool comes in rolls. "We recommend it for the atlantic regions, because it can accumulate moisture and release it without damage, unlike hemp which is mildew," says Alain Drouilleau. Material renewable, recyclable, and inexpensive (13 to 15 €/m2), the sheep wool has two drawbacks : it is not very effective against the heat, and it attracts the moths. Used as insulator, therefore it must absolutely be treated... with an environmentally friendly product naturally!