Valorisation of waste OSB into sustainable mycelium-based composites for insulation applications

The need for the construction industry to reduce its contribution to landfill waste and greenhouse gas emissions is urgent, with engineered wood products such as oriented strand board (OSB) representing a complex and difficult-to-recycle waste stream. As the demand for construction materials increases, it is important to address end-of-life challenges for OSB. Mycelium-based composites (MBCs) offer a promising solution by repurposing waste materials into sustainable products. MBCs are a class of bio-based material made from the colonisation of fungal mycelium on organic substrates, often agricultural or paper waste. MBCs can provide an environmentally friendly end-of-life pathway for waste but also serve as effective insulation materials that can be sustainable alternatives to conventional insulation solutions. Here, MBCs are successfully produced using waste OSB and Trametes versicolor mycelium. The mycelium successfully colonised and bound the OSB substrate, forming that retained their shape after demoulding and drying. Thermal characterisation of the OSB-based MBCs showed a mean thermal conductivity of [Formula: see text] W/m·K, comparable to conventional insulation materials. Importantly, this approach opens up the possibility of including diverse materials as MBC substrates depending on local waste availability and waste challenges. A life cycle assessment (LCA) of the lab-scale production process was conducted to identify key areas of the production process that contribute to environmental impact, with drying being the most energy-intensive stage. The global warming potential (GWP) of OSB-based MBCs was found to be 0.1021 kg CO[Formula: see text] eq per 1 kg of material, lower than conventional insulation materials such as EPS, XPS, and rockwool, and comparable to other MBCs made with alternative substrates. This work highlights the potential of valorising engineered wood waste, such as OSB, through the production of mycelium-based composites. By transforming construction waste into sustainable insulation materials, this study contributes to circular economy practices in the construction industry and supports efforts to reduce environmental impacts.