Straw homes set to be wolfed up
In the famous nursery rhyme, one of the three little pigs is derided for building his house from straw - presenting the big bad wolf with an easy meal.
But maybe the pig was on to something, as the first straw houses to be offered on the open market go on sale.
The team behind the project insist that straw houses could help to meet housing demand in the UK sustainably - and are safe from huffing and puffing .
The homes are the result of an engineering research project led by the University of Bath and specialist architectural firm Modcell.
The seven houses, on a street of traditional brick-built homes in Shirehampton, Bristol, are clad in brick to fit in with the surroundings.
But their prefabricated walls are timber-framed, filled with straw bales and encased in wooden boards.
Homeowners are being promised fuel bills up to 90% cheaper than an equivalent brick-built house and a purchase price less than the cost of the average house in Bristol.
Professor Pete Walker, who led the project to develop and test the construction method, said: "The construction sector must reduce its energy consumption by 50% and its carbon emissions by 80% by 2050, so radical changes are needed to the way we approach house building.
"As a construction material, straw is a low-cost and widely-available food co-product that offers real potential for ultra-low carbon housing throughout the UK.
"Building with straw could be a critical point in our trajectory towards a low-carbon future."
As part of this EU-funded project, Prof Walker and his colleagues have systematically tested and refined the technology, including testing the structural and weight-bearing properties, and its thermal insulation.
"Over the past three years of research we have looked at various aspects of the performance of straw," said Prof Walker.
"Two that particularly come to mind as concerns or apprehension from potential users of straw are fire-resistance and weather-resistance.
"We have conducted a number of fire tests that have demonstrated that fire resistance from straw bale construction is remarkably good and better than many contemporary forms of construction.
"In terms of durability, we have undertaken laboratory tests and undertaken monitoring of existing buildings and we have also done accelerated weather tests.
"The results of all these tests suggest that straw is a very durable construction solution."
Although these are not the first homes in the UK to be built using straw bales, they are the first to be built for any buyer on the open market.
According to the researchers, up to seven million tonnes of straw remains after the production of wheat flour in the UK. Around half of this is effectively discarded due to its low value and is used as animal bedding.
The remaining 3.8 million tonnes of straw could be used to build more than 500,000 new homes, as an average three-bedroom house needs 7.2 tonnes of straw.
There has been a steady increase in straw bale construction around the world, with buildings found in countries including the US, Australia and China.
Straw housing developments are also under way in Cornwall.
At the award-winning straw-built co-housing community in Bramley, Leeds, residents benefited from a 20% lower build cost and 90% cut in bills than the average in the city.
Craig White, director of Bristol-based ModCell, said: "The Q mark industry certification means that straw is now a viable, affordable means of tackling the housing crisis in the UK.
"Using a 'fabric first' approach is ideal for private homes, social housing, and new, innovative projects such as custom-build.
"Straw now offers a simple and effective home-grown solution to the UK's housing needs."