Towards sustainable roofing in Mexico: potential of mycelium-based composites to replace EPS as prefabricated lightweight vaults

Mycelium-based composites (MBCs) are organic materials that could replace expanded polystyrene (EPS) in various applications. In Mexico, prefabricated lightweight vaults used in roofing systems offer a cost-effective, time-efficient alternative for housing. This system is important for low-income groups due to its affordability and quick installation without specialized tools. The research compares the strength, water absorption, and fire resistance of MBCs made with the fungal species Pleurotus ostreatus, Pleurotus djamour, and Ganoderma lucidum, using substrates such as sawdust, straw, and coconut fiber, against commercial EPS. Results show 80% of MBC samples had higher compressive strength, up to 1200 kPa with Ganoderma and 171 kPa with P. ostreatus, without mechanical or hot pressing. All MBC samples exhibited a higher elastic modulus, ignited 30 times slower under heat, but had a density 20 times greater than EPS.