Every time a building is built or demolished, dumpsters full of construction waste head to landfills—and each year in the U.S., the construction and demolition industry generates around twice as much trash as all of the other waste in cities. The materials often can’t easily be recycled. But by redesigning common materials, a U.K.-based startup called Biohm is working to help the industry shift to a circular model.
At a factory a few hours west of London that will open early next year, the company will soon begin mass-producing its first product: insulation made from mycelium, the thread-like roots that connect mushrooms. The material is biodegradable and eliminates other environmental problems caused by typical foam insulation. But it also outperforms the standard product.
“We found that mycelium, or mushroom-based networks and structures, are incredibly similar to the structures that you get in engineered plastic-insulation products,” says Ehab Sayed, founder and director of innovation at Biohm. In tests, they found that the material does a better job of insulating than alternatives like foam, with less thermal conductivity, and in a fire, it’s slower to burn. Tests also suggest that it’s as durable as standard insulation. But unlike standard insulation, it can be safely composted at the end of its life, or easily reused to make more insulation.
The company grows mycelium by agricultural byproducts to the fungus, which helps make the final product carbon negative. Then it lets it grow to the size of a standard insulation panel. “What you’ll end up with is an insulation panel that’s been completely naturally formed,” Sayed says. Once it’s grown to the correct size, it’s cured into a rigid, strong material.
By starting with mushrooms, the material avoids several challenges. Typical foam insulation begins with fossil fuels, which “obviously has an impact on resource depletion on the carbon and energy footprints of the product,” he says. The products are also usually made with a gas that is far more potent than CO2 in terms of climate change, although the industry is introducing newer alternatives because of regulation. Other products can start with natural materials, but then add formaldehyde and other toxic chemicals like flame retardants. On construction sites, the dust from cutting insulation can be unhealthy for workers; even inside a house, insulation can emit volatile organic compounds that reduce indoor air quality.
The company, which is one of the 2021 winners of the Index Award, a prize focused on social impact, is simultaneously developing other green construction materials, including plant-based concrete and a fiberboard alternative made from food waste. It also plans to later launch a new circular construction system that uses all of the materials in combination. Then there are plans for new factories in the U.K. and the Netherlands.
The company’s current facility will produce the insulation at a small scale, with enough for around 30 homes a month. Still, even as it’s first launching, the cost of the product can compete with higher-end insulation. As it scales up production, the cost will come down far enough that the product can be used in affordable housing. The fact that the company uses waste helps reduce the cost. “The only two ingredients are the waste stream for the feedstock, which is a waste that we collect as a waste collection service, and the mycelium, which we culture and grow ourselves in our facilities,” says Sayed. “So you basically have no raw material that you’re having to pay for us to start with, which really makes things more achievable when you’re producing at scale.”
Corrections: We’ve updated this article to reflect that the company does not use sawdust as a feed for the mushrooms and eliminate references to the British Board of Agrément’s rating of the product; the board provides accreditation but does not give official ratings.