Straw - A viable building material?

The BaleHaus@Bath

If the fairytale of The Three Little Pigs has taught us anything, when it comes to building houses stone is the way to go. However a group of researchers at the University of Bath have made a house of straw and hemp to show that the traditionally flimsy materials can be used in construction.

The BaleHaus@Bath is part of a project to show the benefits of renewable resources in the construction of buildings. Traditionally construction requires the use of finite materials and is often damaging to the environment, but straw and hemp are the ultimate environmentally-friendly building materials.

Firstly, they are plentiful and renewable and secondly, they can absorb CO2 giving the buildings a tiny or even a negative carbon footprint. In the BaleHaus@Bath's case, the straw and hemp packed into prefabricated cells of timber rendered with a lime-based coat. Straw also has high insulating properties meaning that in theory, heating costs would be lower than usual saving money and minimising environmental impact.

"Low carbon building materials"

A recent fire resistance test that saw the panels forced to endure heat for more than 30 minutes saw them not even fail after two hours. To see how the straw fares during construction, the research team placed sensors inside the panels.

Professor Peter Walker, Director of the Centre, is leading the research. On the Bath University website, he said "The environmental impact of the construction industry is huge. For example, it is estimated that worldwide the manufacture of cement contributes up to ten per cent of all industrial carbon dioxide emissions.

"We are looking at a variety of low carbon building materials including crop-based materials, innovative uses of traditional materials and developing low carbon cements and concretes to reduce impact of new infrastructure.

"As well as reducing the environmental footprint, many low carbon building materials offer other benefits, including healthier living through higher levels of thermal insulation and regulation of humidity levels."

Dr Katharine Beadle, who has been keeping a blog on the house's construction, states that "over the next year the house will be extensively monitored and various tests carried out".

Christopher Gross from the University's Building Research Establishment Centre in Innovative Construction Materials will also be checking how the straw and hemp affects the house's insulating properties, humidity levels, air tightness and sound insulation qualities.

Eco-friendly homes

The idea of a 'straw house' was conceived by TV presenter Kevin McCloud who built an eco-friendly house in six days for the Grand Designs Live exhibition. He will officially open the BaleHaus@Bath later today.

Speaking to the BBC, he said, "I expect the results will show people that we can minimise the use of highly processed materials in building and genuinely make use of such sustainable building materials," he said.

"It's vital that we encourage people to recycle, insulate and minimise the use of fossil fuels to keep our buildings warm."

Click here to see videos of the BaleHaus@Bath.

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