A common fungus can break down hard-to-recycle construction waste and turn it into sustainable insulation that rivals traditional and petrochemical-based options, according to researchers at the University of Bath.

The construction industry is a major contributor to carbon emissions and landfill waste worldwide. Wood waste makes up almost a third of construction and demolition waste and almost 10% of total landfill waste. To add strength and prevent rotting, much of this wood is treated with resins, making it hard to recycle and releasing toxic chemicals and greenhouse gases when decomposing.

Researchers at Bath are tackling the problem with nature, feeding the waste wood to fungi. As fungi grow, they send out a network of root-like threads which break down organic material and absorb nutrients. This network, known as the mycelium, acts like a glue binding the material into a natural, thermally insulating and fire-resistant composite.

Joni Wildman, lead author on the study and researcher in the Department of Architecture and Civil Engineering, said: “One of the biggest challenges in construction is what happens to materials at the end of their life.

“Mycelium-based materials are a novel option that is gaining attention, but this is the first time we’ve shown the fungus doing two jobs at once; creating a sustainable insulation material and transforming challenging, and potentially harmful, waste into something valuable.”

Locally found fungi break down engineered wood

Mycelium-based composites are being tested as greener alternatives to traditional insulation materials; however, many are based on fast-growing crops or byproducts from the wood and paper industry. While these are classed as waste materials, they have valuable uses in animal feeds, textiles and pulping.

Oriented strand board (OSB) is an engineered wood product made from compressed wood flakes bonded with synthetic resins. It’s used in interior walls, flooring and roof decking, and the waste is often burned or buried, posing a risk to health and the environment.

The researchers chipped and soaked waste OSB before adding ‘Trametes versicolor’, a wood-rotting fungus known as turkey tail that is found throughout UK woodlands. Despite containing synthetic additives, the team showed that the fungus grew successfully on OSB, creating a sturdy and consistent material.

They also found the thermal performance of the resulting biomaterial was on a par with conventional insulation products, and carbon emissions were more than 10 times lower in production than conventional materials, including expanded polystyrene, extruded polystyrene and mineral wool.

Turning innovation into sustainable solutions

This study demonstrates how some of the building industry’s most complex waste can offer a practical solution towards more circular materials that don’t compromise on performance.

Dr Andrew Shea, the project supervisor and a researcher in the Department of Architecture and Civil Engineering, said: “This is an exciting step towards using biology to rethink how we make and use materials in building construction.”

Joni added: “As we test this concept further, we could see these materials being used in a range of applications, like packaging, soundproofing, or even textiles, replacing high-carbon materials with biodegradable and circular alternatives.”

While the bio-based material produced far fewer carbon emissions than traditional insulation, the team noted that energy use, especially during drying, was the largest source of emissions. They plan to explore how the process can be scaled up to industrial production, while cutting the energy demands and impact of manufacturing.

Looking forwards, they will monitor how the material performs over time, assessing durability and how it behaves in different moisture conditions. They will also investigate other challenging waste streams, such as plastics or toxic materials, that can be transformed into fungi-based materials for more sustainable construction.