Greening the City

Biosourced materials aren't necessarily green

Site map
All the texts
Credits
Home page

From yak wool yurts and mud huts to the most modern constructions, materials of natural origin have always found a use in building.   And now, with increasing awareness of ecological issues, such materials are being used even more. They play a role in the structure, cladding and above all insulation of buildings. As well as conventional biosourced insulating materials such as cork and wood fibers, many other materials have recently made a breakthrough, such as those based on hemp, cotton or flax fibers, straw, duck feathers, sheep's wool, etc. Recently, we've even seen insulating materials based on algae and oyster shells! Some of these biosourced materials are treated in order to prevent the occurrence of mites, clothes-moths or fungi. This is why it's important to verify not only their technical performance but also their inoffensiveness to future occupants (1). As for their added value, this theoretically concerns the 'grey energy' that is saved by using such materials, in other words all the energy required to produce them and transport them to the construction site. However, with regard to its energy budget, a panel that has traveled several thousand kilometers before being installed may not be quite so green after all, even if it is made of cork!

1 – See the French reference data base on the environmental and health performance of building materials (INIES) http://www.inies.fr/