In-depth evaluation of physical properties of mycelium-based bio composites for use as facade insulation material

With the aim of working toward the objective of nearly energy-neutral buildings by 2050, this study focuses on the development of mycelium-based insulation materials as a sustainable alternative to conventional insulation materials such as expanded and extruded polystyrene. To characterize the fundamental properties of such materials and propose strategies for precisely tuning key properties, organic waste products and inorganic additives were investigated as potential substrate addition, and various building physics parameters were analyzed using two different fungal species. The methodology involved the fabrication of samples from mycelium-based insulation materials in three steps: substrate preparation, growth phase, and drying. These samples were then comprehensively examined for their building-physical properties, including thermal conductivity, water vapor diffusion resistance, and capillary water absorption. The main findings indicate that the selection of additives significantly impacts the material properties. Samples with base substrate and hemp additive exhibited the best building physics properties in terms of thermal conductivity (λ_H = 0.046–0.050 W/(m K)) and water vapor diffusion resistance (µ_H = 3–4). These materials have the potential to be used as insulation materials in construction, although their physical properties are less favorable compared to conventional materials such as polystyrene and mineral wool. However, these materials stand out, particularly in their high degree of recyclability. This research innovatively applies Basidiomycota fungi for insulation production, exploring substrate compositions. It characterizes mycelium-based insulation and identifies optimization opportunities for construction, advancing sustainable building materials and modern physics. These findings propel mycelium insulation development, fostering a greener construction industry.