Can We Recycle Cities?
When I sit down in the playroom with my toddler to build a city, we use a classic set of wood blocks.
There are tall and short rectangles, squares, triangles, and cylinders that make excellent columns. Together we build fantastical arches and towers. I usually only get to admire the work for an instant before it all comes tumbling down with the ferocity of a three-year-old’s fist. And then we do it all again, using the exact same blocks.
If only this was how building construction really worked. Instead, when you tear down a building, 90 percent of it ends up in a landfill. Construction and demolition waste is the biggest contributor to landfills in both the United States and Europe . The result is not just an architectural shame but an environmental tragedy.
But what if buildings could be recycled just like my kid’s cityscape? In a 10,000 square foot barn in Cleveland stands a heavy steel apparatus that looks a lot like a medieval torture device. It’s part of a system invented by architect Christopher Maurer called the Biocycler that turns construction debris into wood-like bricks and panels by binding it with mycelium, the root-like structure of mushrooms.
Imagine you’re a piece of lumber from a Victorian-era Midwestern home that has just been demolished. Instead of heading to a landfill, you are hoisted into a wood chipper that turns you into sawdust. You are then steam treated and seeded with mycelium, which grows all around you and binds your sawdust fibers together. As this damp mixture dries, you take shape: bricks, panels, or other forms. Finally, you are cooked at 100 degrees Celsius, like a loaf of bread. When you come out of the oven, you are pressed into a biomaterial, ready for use in a new building.
“Fungus is famous for bringing life from death,” says Maurer, founder of Redhouse Architecture, from inside the barn he and his team transformed into a hybrid design studio, industrial grow house, and manufacturing plant. “We’re continuing to find ways that this is superior to common building materials.”
Mycelium can play roles that would ordinarily require multiple materials in a traditional building. The bricks are strong enough to bear loads like cinder blocks, insulate like fiberglass, and withstand fire like gypsum.
In the 1970s, Swiss architect Walter Stahel suggested the concept of circular economies, or loops of “reuse, repair, and remanufacture,” to reduce waste from consumer products, including buildings.  By the time Michael Braungart and William McDonough published Cradle to Cradle in 2002, a small but growing group of architects had been trying to make the building industry more circular and focused on reducing waste. 
In 2015, Copenhagen-based 3XN Architects proposed how new highrises could be built on the core of older buildings, preserving their existing structure rather than tearing them down. All new components would be modular and built to be readjusted and shuffled as offices turned into apartments, or taken apart and used again for entirely new purposes. 
“We talk about buildings as material banks,” says 3XN’s founder Kasper Guldager Jensen. “You can think of buildings as a resource center with intrinsic value. And when you have to take a building down, you actually see it as valuable.” 3XN has so far completed one concept building and has a handful in development.
Maurer’s idea may be even more radical: attempting to use demolished buildings as fodder for mycelium. Architects have been trying to use mycelium as a building material since artist Phil Ross developed the concept of mycotecture as early as 2009. Ross built pup tent-sized arches of mycelium bricks for museum exhibitions. Visitors could sip tea from mushrooms growing on the installation. A few years later, Ecovative Design, a mycelium products company, designed its own mycelium insulation, an attempt to prove that cradle-to-cradle circularity could work in construction . Finally, when David Benjamin won the Museum of Modern Art’s Young Architects Program in 2014 for a project to create mycelium towers over the courtyard at MoMA PS1, a trend had been set.
Sometimes called “nature’s glue,” advocates see mycelium as the Swiss Army knife of sustainable design, because it can be grown from agricultural and industrial byproducts and can make bricks, packing foam, furniture, and even leather.
Maurer was inspired after working for four years in Malawi and Rwanda for studioMDA and Mass Design Group to build affordable, sustainable housing in limited resource areas. When he came home to Cleveland in 2013, he thought that perhaps the grand idea he was chasing in Africa — using recycled, local materials to build new buildings — could also combat the housing crisis in suburban America.
Much of the area around Maurer’s studio never recovered from the 2008 recession. Homes across Ohio have been abandoned, foreclosed, or left empty, rotting, and unsafe. In eight cities across the state, over 41,000 homes will need to be demolished before 2021 as part of a national strategy for rebuilding the nation’s cities, according to the Brookings Institution. 
“There are always going to be these homes that need to be demolished, so the goal is to put them to good use,” Maurer says.
Still, recycling demolished buildings into new materials has a long way to go. First, there is the basic life cycle analysis with regards to the costs of water, time, and energy of recycling a building with mycelium. Second, there are the safety hurdles. Construction materials are heavily regulated by the American Society for Testing and Materials (ASTM), an international group that standardizes construction specifications, practices, and test methods. Construction products must undergo strenuous weather tests, fire tests, smoke tests, rot and mold tests, and breaking tests, all using professional equipment and standardized environments. These tests are prohibitively expensive for small firms like Redhouse.
While Mauer waits for the US construction industry to catch up, he has turned his attention back to Africa. He is partnering with the government of Namibia and the MIT Center for Bits and Atoms to build a community of mycelium dwellings in a region called Brakwater. It’s a proof of concept for mycelium architecture. It also creates a double circular economy by allowing farmers to cultivate mushrooms generated from the building process for food.
With his latest project in mind, Maurer dismisses the high hurdles for mycelium buildings in his hometown. “It’s futuristic, maybe,” he admits. “But how hard can it be to recycle a house?”
 “Sustainable Management of Construction and Demolition Materials.” EPA, Environmental Protection Agency, 26 May 2020, www.epa.gov/smm/sustainable-management-construction-and-demolition-materials.
 EU Construction and Demolition Waste Protocol and Guidelines. 4 Oct. 2018,
 Stahel, Walter R., and Reday-Mulvey Geneviève. Jobs for Tomorrow: the Potential for Substituting Manpower for Energy. Vantage Press, 1981.
 McDonough, William, and Michael Braungart. Cradle to Cradle: Remaking the Way We Make Things. Vintage, 2002.
 Guldager Jensen, Kasper and John Sommer. Building a Circular Future. GXN, 2015.
 Hook, Susan Van. “Testing the Viability of Agricultural Byproducts as a Replacement for Mineral Particles in a Novel, Low Embodied Energy, Construction Material.” EPA, Environmental Protection Agency, 22 Oct. 2009, cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.abstractDetail/abstract/8953/report/F.
 Mallach, Alan. Laying the Groundwork for Change: Demolition, urban strategy, and policy reform. Brookings Metropolitan Policy Program. September, 2012.
Alex Pearlman is a writer, reporter, and bioethicist, currently at Biodesigned magazine and University of Pennsylvania. Alex is a unique biotech policy nerd/digital journalist/product manager with experience that spans from managing agile products, to founding a startup, to reporting and editing for digital news organizations, to researching humanity’s next big thing: biological inequality. Please check out her CV on LinkedIn or peep some quick thoughts on my Medium account.