Systematic review of mycelium-based composites as sustainable insulators for carbon-neutral building envelopes

Due to the embodied effects of traditional insulation materials as well as the energy required for building operations, the construction industry contributes significantly to global carbon emissions. Mycelium-based composites (MBCs) as bio-based insulation materials for carbon-neutral building-envelope applications are the focus of this study's methodical review. Several aspects are also investigated including how fungal species, substrate composition, reinforcement strategy and processing techniques affect performance, evaluating their thermal and specific functional properties, including durability-related behaviour and cost relevance, and evaluating their environmental potential, embodied carbon implications, and circular-economy relevance in comparison to traditional insulation materials. This paper discusses published research on MBCs' fabrication, thermal conductivity, mechanical properties, durability-related constraints, circularity, embodied carbon and practical applicability using a PRISMA-based systematic review and life cycle assessment-oriented analytical framework. Results show that MBCs provide low density, biodegradability, the use of renewable feedstock and promising thermal performance. With a thermal conductivity of 0.0404 W/m·K, mycelium-hemp composites demonstrated the best insulating behaviour among the systems under consideration. The review also demonstrates that MBCs can help lower lifecycle carbon emissions, but the lack of standardization, moisture sensitivity, poor durability evidence and unclear large-scale cost-effectiveness continue to hinder their broader implementation. All things considered, MBCs exhibit great promise for semi-protected and non-load-bearing building-envelope insulation applications.