UK Straw Supply Could Support 300,000 Low-Carbon Homes Annually

The UK produces enough agricultural straw to help build up to 300,000 low-rise homes each year. New research from the University of Bath shows that material supply is not the main obstacle. Instead, weak supply chains, unclear rules and low industry acceptance slow its wider use.

A Renewable Building Material

The UK produces around 9.9 million tonnes of straw every year as a co-product of cereal farming. Farmers use it for animal bedding, livestock feed, soil improvement and energy production. It also supports horticulture and mushroom farming. However, builders use very little straw in UK housing. Fewer than 20 new homes incorporate it each year.

Straw offers a renewable alternative to carbon-intensive materials such as concrete and steel. Builders can use straw bales to create structural and well-insulated walls in low-rise buildings. These walls can also regulate moisture and support healthy indoor air.

During growth, cereal crops absorb carbon dioxide from the atmosphere. Using the straw in buildings keeps part of this biogenic carbon stored for the building’s lifespan. The researchers estimate that large-scale straw construction could store between 1.8 and 3.1 million tonnes of carbon dioxide each year.

The approach could also benefit farmers. Selling straw for construction could turn an agricultural co-product into a more valuable material and create an extra source of income.

Enough Straw To Meet Housing Demand

The research team examined current straw uses and tested several ways to direct more of the supply towards construction. Moving straw from sectors such as bioenergy and industry could provide enough material for 300,000 low-rise buildings.

Another option involves using straw that farmers currently leave in fields. Around 60% of this amount could meet the same construction demand. Growing extra straw on unused land could supply about 163,000 homes. Other sources would still need to cover the remaining demand.

The researchers also considered changes in crop yields and demand. Even under these changing conditions, the UK would still have enough straw for large-scale construction.

Barriers Beyond Material Supply

Several practical and economic issues restrict the use of straw. The UK lacks strong supply links between farms, processors and building sites. In addition, only a limited number of contractors have experience with straw construction.

Storage and transport create further difficulties because cereal farming varies across the country. Some straw building methods also take more time than standard construction. Meanwhile, developers, lenders and insurers may view alternative materials as a greater risk.

The researchers argue that clear regulations, training, policy support and market incentives could address these barriers. Such measures could help straw construction support housing targets while reducing emissions from new buildings.

Source & photo: University of Bath