Straw house has good fire resistance

A house built of prefabricated straw-bale and hemp panels has fire resistance as good as houses built of conventional building materials, according to researchers at Bath University.

The researchers tested a prefabricated panel for fire safety by exposing it to temperatures over 1,000°C. To reach the required standard, the panel had to withstand the heat for more than 30 minutes. More than two hours later – four times as long as required – the panel had still not failed.

The panels have been used to build an environmentally friendly house called BaleHaus@Bath, which aims to demonstrate how renewable building materials can be used for homes of the future.

The BaleHaus is composed of prefabricated panels made of a structural timber frame filled in with straw bales or hemp and rendered with a breathable lime-based system. It is the creation of White Design in Bristol and Integral Structural Design in Bath.

Due to the high insulating properties of the panels, the BaleHaus minimises heating requirements, reducing heating bills in housing by up to 85 per cent and lowering CO2 emissions by 60 per cent.

The research work on BaleHaus has been funded by Carbon Connections and the Technology Strategy Board. Researchers Dr Katharine Beadle and Christopher Gross, from the University’s BRE Centre in Innovative Construction Materials, will be monitoring the house for a year for its insulating properties, humidity levels, air-tightness and sound-insulation qualities to assess the performance of straw and hemp as building materials.

Prof Pete Walker, director of the University’s BRE Centre in Innovative Construction Materials, said: ‘Straw is an ideal environmentally friendly building material because it is renewable and is a byproduct of existing farming production.’

Other industrial partners on the research project are Agrifibre Technologies, Lime Technology, Eurban, the Centre for Window & Cladding Technology, and Willmott Dixon.