ECO-INNOVATIONat the heart of European policies
A group of seven houses constructed from highly compacted straw has gone on sale in Bristol, United Kingdom, following extensive testing to prove the safety and environmental performance of the straw panels, which was carried out with assistance from a European Union-funded eco-innovation project.
The seven houses are, according to the developers, Modcell and Connolly-Callaghan, “believed to be the world's first commercially available straw eco-homes.” The construction of the houses was able to go ahead following a rigorous certification process that tested the energy performance, fire safety and weather-resilience of the straw panels. The certification gives the proof of viability of the straw panels that lenders and insurers need to provide mortgages and insurance to buyers of the properties.
The straw panels use an environmentally-friendly by-product from the growing of wheat. About 3.8 million tonnes of waste straw is estimated to be produced in the UK each year. To make the panels, the straw is packed into wooden frames so tightly that little air is able to penetrate. This gives the straw bales excellent insulation properties and makes them fireproof because of a lack of oxygen on which a fire can feed.
According to the developers of the Bristol houses, straw offers several environmental benefits as a construction material. “Straw homes have one of the lowest carbon footprints available, with many buildings being net carbon-negative,” according to Modcell. The company cites a previous construction project using straw bales which was 20% cheaper than using standard materials, and generated a 90% reduction in energy bills compared to traditional houses.
The process of certifying the safety of the straw bales for construction was done at the University of Bath in south-west England through EUROCELL, a project of the European Union's Competitiveness and Innovation Programme Eco-innovation initiative. A demonstration “Balehaus” was built on the university campus and subjected to intensive testing, including exposure of the panels to heavy rain and extreme temperatures as low as -20 degrees Celsius and up to 50 degrees Celsius.
Straw panels have been used in a range of other projects (see the previous article at http://ec.europa.eu/environment/ecoap/about-eco-innovation/policies-matters/eu/20130409-houses-built-of-straw_en.htm). But the construction of the seven houses in Bristol is the first standardised development of housing using the bales, and could signal the start of a straw panel construction boom. Since the sales were announced, there has been a high level of buyer interest, and the houses are expected to sell quickly.
Further information is available at http://www.modcell.com/completed-projects/shirehampton-eco-homes-bristol/