Could Mushrooms Replace Foam? Mycelium Insulation Put to the Test in Alaska

Could Mycelium Replace Petroleum-Based Insulation?

Just beneath the forest floor, networks of fungal threads called mycelium knit together, decomposing wood and sometimes producing the mushrooms we see aboveground. Researchers at the University of Alaska and the National Renewable Energy Laboratory are harnessing that natural process to grow compostable insulation panels aimed at improving housing in Alaska’s extreme climate.

Why Alaska Needs New Approaches

Rural Alaskan communities face limited infrastructure, severe weather and the accelerating impacts of climate change—erosion, flooding, thawing permafrost and wildfires—that increase the need for safe, energy-efficient, affordable housing. Seasonal temperature swings in places like the Yukon Flats can range from -78°F in winter to 100°F in summer, making durable insulation both technically challenging and costly.

From Beetle-Killed Spruce to Insulation Boards

Led by mycologist Philippe Amstislavski at the University of Alaska Anchorage and research engineer Robbin Garber-Slaght at the National Renewable Energy Laboratory, the team developed panels using locally sourced wood pulp and a hearty native fungal strain. The project began partly to replace non-biodegradable foam and packaging that often litters tundra and waterways.

The manufacturing process is simple in concept: a frothy slurry of wood pulp and water is mixed with a fungal culture and poured into molds. The mycelium colonizes the feedstock in tray racks, binding it into a solid form. After curing with heat, the result is a rigid, breathable board that resists water and approaches the thermal performance of conventional expanded polystyrene.

“Now you are basically wrapping your house in the plastic bag. It doesn’t breathe,” said Philippe Amstislavski, describing the drawbacks of current plastic-based exterior insulation methods.

Testing and Performance

To simulate extreme conditions, the researchers built a mobile test lab in Fairbanks resembling a tiny house with nine instrumented wall panels. The lab monitors temperature and humidity responses across controlled cycles. The team also completed a nine-year field review of an installed panel and reports that it remained free of mold and continued performing as expected in Fairbanks’ harsh environment.

“It looked like a bunch of sawdust with fungus on it” in early trials, Garber-Slaght said, noting the many iterations required to reach consistent, structurally sound boards. Today the lab produces uniform, cost-effective, 100 percent compostable panels.

Benefits, Limits and Next Steps

Potential benefits include reduced plastic waste, use of local biomass (including beetle-killed spruce), a breathable building envelope that limits mold risk, and the ability to sequester carbon in the product. Challenges remain: a biodegradable material may never perfectly match the long-term waterproofing and durability of petroleum products, and achieving a fully carbon-neutral lifecycle would require sustainably sourced pulp and renewable manufacturing energy.

Early commercial interest has emerged for replacing plastic-foam fish coolers, and the team hopes to scale for building envelopes. “I would love to just grow a building,” Garber-Slaght said, while acknowledging that such ambitions are still some way off.

Bottom line: Mycelium-based insulation shows promising thermal performance and environmental benefits in Alaska’s extreme climates, but broader adoption depends on further longevity studies, lifecycle analysis, and scalable manufacturing.