Ecological materials: a mushroom brick and a wooden block
However, more ecological solutions have been around for a long time, such as mud or hemp bricks, or concrete made from flax fibers. In a more original and much more recent way, bricks of a new nature have appeared: the wooden brick, born in the forests devastated by the storm of 1999, and the mushroom brick, inspired by a traditional Indonesian cake.
Ecological concrete blocks made of wood
The idea of a wooden brick, or wooden block ("BVB"), is not quite recent. The 1999 storm had left mountains of timber in its path that could not be used for construction, at least not using the usual techniques. There remained the possibility of cutting compact blocks of wood, similar to concrete blocks. And the result was surprising. Five times lighter, BVB is also six times cheaper to build, while being significantly cleaner than concrete.
Far from producing greenhouse gases, on the contrary, wood traps CO2 throughout its life. Recyclable, participating in the sustainable management of French forests, this “eco-material” is also an excellent thermal insulator, far superior to concrete, and also a very good acoustic insulator. BVB walls are also very dense, allowing them to withstand fire at least as well as concrete walls.
On a practical level, the realization of constructions in BVB is somewhat like a game of lego. There is no question here of cement to bind the concrete blocks, but rather of screws and nails. Ideal for self-construction, this technique however requires good knowledge of DIY, and a certain know-how.
Finally, BVB construction is much more economical than concrete construction, and much faster, as the wood does not need to dry. Once treated against parasites, BVB walls have a foolproof longevity, again likely to compete very seriously with concrete. An advantage which significantly reduces the initial investment, the BVB being on average three to four times more expensive than the classic concrete block.
A mushroom brick inspired by an Indonesian cake
Even more revolutionary than the wooden brick, there is the mushroom brick, created by an Indonesian company, Mycotech. The technique uses the mycelium of the fungus, which is the vegetative and filamentous part of the fungus, roughly comparable to the roots of chlorophyll plants. The mycelium has a strong capacity to penetrate the substrate, effectively breaking down the organic matter encountered. Mycotech's idea is also inspired by a traditional Indonesian soy-based food product, “tempeh”, using the same properties of mycelium.
The soybeans are colonized by the mycelium, providing a very compact cake. Mycotech therefore reused the concept, by letting the mycelium stretch into the substrate, giving it the desired shape, in this case that of a brick again very compact. The product obtained is advertised as very strong, similar to a classic terracotta brick, but also powerfully insulating, non-flammable and waterproof.
By its very nature, the Mycotech brick is a model of sustainable development, emitting no embodied energy, on the contrary storing CO2 and avoiding the importation of expensive construction materials, and composed only of natural elements. The substrate used for the growth of the mycelium comes from plant waste produced by Indonesian agriculture (120 million tonnes per year): corn stalks, or in particular wood chips.
Thus, in addition to drastically reducing production costs, this method makes it possible to promote plant waste from Indonesian agriculture, until now destined for incineration for lack of anything better. Small-scale farmers are also benefiting from it, profiting from materials previously of no market value. The economic model devised by Mycotech is thus proving to be both ecological, economical, and profitable for all, a not so common finding.