Fungi as sustainable insulation for homes

When you think of fungi in your home, you might picture moldy walls or damp basements. But what if I told you that fungi could be the key to a more sustainable future? The construction industry has a problem: carbon emissions. This sector accounts for a staggering 37% of global carbon emissions[1], which are directly causing global warming and the consequential climate crisis. These emissions include not just the energy required to keep our buildings functional but also the manufacturing and transport of building materials. With a considerable portion of energy in homes going towards heating and cooling, the need for effective insulation has never been more critical. This is especially true as temperature extremes become more frequent and severe, compounding the current problem; £1.4 billion each year is spent by the NHS on the health consequences of inadequate home heating[2], the WHO recognises damp as a significant health risk[3], and fuel poverty is daily struggle for many families.

Traditional insulation like expanded polystyrene and mineral wool are effective insulation materials but come with unignorable environmental costs. They're energy-intensive to produce, take thousands of years to degrade, can be toxic and flammable, and drain natural resources. Enter fungi- specifically, fungal mycelium.

Mycelium, the vegetative part of a fungus, consists of a branching mass of hyphal cells that form a network structure. These networks grow in search of food, secreting enzymes to break down organic matter, which the fungus then absorbs. It is the remarkable digestion abilities of fungi that can be harnessed to create mycelium-based composites, offering a sustainable solution for home insulation.

Mycelium-based composites are made by growing mycelium on substrates like wood chips, agricultural waste, and even waste from the construction industry itself. The substrate is inoculated with mycelium where the fungus will grow and digest the material, forming a natural adhesive. Once fully colonized, the composite is dried to stop the growth and kill the living organism, resulting in an inert, bio-based material with insulating properties.

Mycelium-based composites have shown to be as effective as traditional insulation materials, as well as being fire resistant and acoustically insulative[4]. The mycelium networks bind agricultural waste into porous structures that trap insulating pockets of air. However, there's still work to be done to optimise and accurately characterize their thermal properties; with countless fungal species and substrates yet to be explored, the possibilities are vast. Further research into growth conditions, different manufacturing methods, and post-processing techniques could fine-tune the material's properties for specific uses and allow for varied and region-specific waste streams to be used as the substrate.

Despite the benefits, challenges remain. Scaling up production is a major hurdle, as current methods are labor-intensive and require precise control of growth conditions; the factories that would produce fungal materials would be very different to those used to make petrochemical- based insulation. Advances in biotechnology and manufacturing processes hold promise for meeting commercial demands. Market acceptance is another obstacle; builders and consumers need to be educated about the benefits and performance of mycelium composites if they are to be widely adopted. While members of the British Mycological Society appreciate fungi's diverse and important ecological and biotechnological roles, the general public can be mycophobic. Demonstration projects and certifications will be crucial in building confidence and establishing mycelium composites as reliable options. Even though fungi are known for defying norms and surprising us, they still need to meet building codes and safety regulations!

Mycelium-based composites represent a significant leap forward in sustainable building materials. By harnessing fungi's natural growth processes, these composites offer an eco-friendly alternative to traditional insulation, with the added benefits of biodegradability, renewable resources, and low-energy production. As research and development continue, mycelium composites have the potential to become a mainstream solution, contributing to a more sustainable and resilient built environment.

So, whilst mushrooms popping up in your shower is still a cause for concern, fungi in your homes could be a new frontier in the quest for more sustainable practices in the construction industry. Mycelium-based composites are an exciting and promising area of applied mycology with the potential to help create a more sustainable world and environmentally friendly homes.

References:
[1] United Nations Environment Programme (UNEP). (2023). Building materials and the climate: Constructing a new future. UNEP.
[2] BRE Group. (2021). The cost of poor housing in the UK. BRE.
[3] Office for Health Improvement and Disparities (OHID). (2022). Understanding and addressing the health risks of damp and mould in the home. Department of Health and Social Care (DHSC), UK Government.
[4] Jones, M., Huynh, T., Dekiwadia, C., Daver, F., & John, S. (2020). Engineered mycelium composite construction materials from fungal biorefineries: A critical review. Materials & Design, 187, 108397.