Mycelium-bound building materials

Sustainable Construction, KIT Karlsruhe; Alternative Construction Materials, FCL, Singapore-ETH Centre

Against the background of the climate change and the depletion of natural fossil resources, it is clear that in the future we will not be able to build our cities the way we do today. Biologically produced and degradable materials play a key role in the development and establishment of circular and sustainable construction systems. Until now, natural resources have been extracted from the earth and disposed of in a linear process. This approach has profound consequences for our planet. The fungal research of the Professorship of Sustainable Construction at KIT Karlsruhe aims at establishing new biological cycles in the construction industry.

The mycelium-bound building materials consist of renewable raw materials and are produced using biological processes.

The picture of the fruiting bodies of fungi is very familiar to us. The mycelium, a kind of extensive underground root network, normally remains invisible. It grows very extensively, densely and homogeneously and represents the digestive system of the organism.

In the production of mycelium-bound building elements, the binding power that this root network provides is used. Agricultural waste or waste from the wood and food industry serves as food for the fungus and thus as a starting material for the growth process. Like a natural adhesive, the mycelium network binds the organic substrate as it grows. This process takes place in specially made moulds, so that any geometry can be produced.

The Professorship of Sustainable Construction at the KIT in Karlsruhe produces these grown building materials in form of different building blocks or panel materials. They combine several properties: thermal and acoustic insulation, tailor-made mechanical strength (comparable to that of polystyrene foams up to that of plywood), biodegradability and low energy consumption during production.

The growth of mycelium biocomposites takes place in controlled conditions in the laboratory and is therefore independent of a country's climate and the availability of fertile soil.

In the MycoTree project, a spatial branching structure, building blocks of mycelium were used as load-bearing components. Thanks to a sophisticated geometry, the shape follows the course of the forces, whereby the relatively weak material is kept under pressure and can thus be used as a load-bearing component. The MycoTree was created in collaboration with the Block Research Group at the Swiss Federal Institute of Technology (ETH) Zurich. Its entire structure consists of mycelium-bound building materials and connecting elements made of bamboo.