To choose to build in an ecological way is not attached to the topicality. It has been already millenia that our ancestors build ecological by using the matters at their disposal. The technique of cob is part of these means of construction and exists since years and is even always applied in certain countries of the world.
Building technique in cob
Construction in cob implies the use of a mixture of ground and plants on a timber structure called half-timbering. Relatively simple to implement, the use of cob is a perfect solution for auto--construction.
Half-timbering is composed of a framework out of wooden and cob forms the roughcasting which fills this framework to form walls.
The matters used for the composition of the walls are available in quantity in the medium which surrounds you. The manufacturing costs will thus be reduced considerably.
The principle of cob is simple. The raw material is made up of a mixture of argillaceous ground, straw, sand and lime. Completely natural elements.
The ground must be removed beforehand from these stones then versed in a mixer of type concrete-mixer if you do not want to make it with the hand, with straw or another vegetable fiber as well as water, that one mixes until obtaining a homogeneous substance. The quantity of water used is not as considerable as one could believe it.
The mixture is then applied to the formed half-timbering of a network of spindles out of wooden and beams. For an optimal installation, pose nails of 6 cm at least a little everywhere on the timber structure to make hold cob on the walls.
Three weeks after the display of cob, one can proceed to the coating of the walls to obtain more sealing, to equalize the whole, but also to have a smoother effect.
Advantages and disadvantages of cob
The main advantage of the use of cob is of course the weak environmental impact to build. The matters are available locally and at will according to your site.
Completely biodegradable, it is a éco material par excellence. You can even use natural pigments for the color of your walls. What completely reduces the negative consequences to the environment.
Cob constitutes also a good heat insulator and sound. Qualities of the ground make this kind of material, a substance which absorbs perfectly the ambient moisture and which can restore it. Thermal inertia is also considerable making it possible to ensure a stable temperature within the house.
Solid and profiting from a long longevity, this kind of construction economically returns more profitable than a traditional construction at the time of the phase of construction and in its use of dwelling. The energy performances of this kind of construction are rather considerable, it uses in particular only 3% of the energy used in a concrete construction.
However, it is necessary to take care to cover the walls external of sand or very fine clay a coating or lime to improve the lifetime of the frame.
On the other hand, the building site can require more efforts which are proportional in keeping with project. Indeed, a small construction can require up to 15 tons of ground.
In the same way, the construction standards not having been established yet, constructions in cob are not accepted by the bankers as a mortage pledge. |
