A group of universities in the UK and France are investigating the performance of waste materials and bio-based co-products as alternative building insulation materials. 

Wheat straw bales, rapeseed stalks and recycled duvets are the three materials being constructed into identical prototype wall panels for evaluation. 

Measuring 150mm thick by 1.1 metre square, and fitted with 9mm plywood on either side, these panels will be tested against each other, as well as industry-standard insulation, for six weeks in a state-of-the-art environmental chamber. 

Two tests will be applied: the first will apply an increasing temperature to one side of the panels to calculate how much energy is required to increase the temperature on the other side of the panel. 

The second test involves increasing the humidity to evaluate how each material maintains and holds moisture. 

Each panel will contain probes that measure relative humidity, interior and exterior temperature, and heat flux.

“This is the first time these materials will have been tested in such a robust scientific way allowing us to accurately assess their thermal performance against each other as well as against industry standard insulation,” Research Associate in the University of Bath’s Department of Architecture & Civil Engineering, Dr Shawn Platt, said.

Previous research has shown the performance of wheat straw and straw bales as energy efficient and sustainable building materials. In the UK, up to 3.8 million tonnes of straw are leftover and discarded after the production of wheat flour due to its low value. It is estimated this amount could be used to build over 500,000 new homes in the UK.

Meanwhile, duvets are treated as an industrial waste product, with an estimated 61,900 tonnes of duvets and pillows entering the waste stream every year. A majority of it is sent to landfill or simply burned, while the manufacture of consumer goods like polyester duvets releases harmful greenhouse gases. 

Corn stalk, on the other hand, is currently underused in maize grain crops, with 50 per cent returning to soil. 

By testing these materials, researchers hope to identify them as viable waste materials for building insulation—both to reduce dependency on natural resources used in traditional insulation, such as glass wool and rock wool, and to significantly reduce the emissions associated with construction. 

“It is important we continue to play our part in reducing greenhouse gas emissions and the potential to use waste and co-products as potential future alternatives for building insulation, which could significantly help the construction sector become more sustainable and environmentally friendly,” Dr Platt added.

The research project is a joint collaboration between the Universities of Bath, Brighton and UniLaSalle in Rouen, France, as well as five other academic and non-academic partners. It is being funded by the Interreg VA France (Channel) England Program—an EU program set up to foster economic development between the south of the UK and north of France.