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Houses of straw
This article by Andrew Bibby, in a slightly different form, was first published in The Observer, 2005
You can huff and you can puff as much as you like, but you won't convince members of Britain's Straw Bale Building Association that there's anything wrong with houses made of straw.
The idea of making the walls for a building by simply piling up ordinary farm-supplied bales of straw, rather than struggling with breeze-blocks and mortar, has been slowly attracting attention in Britain in recent years. There are obvious advantages for those who want to be environmentally conscious. As Jon Hollely, director of the building control and inspection company JHAI Ltd, points out, straw bales beat conventional concrete blocks hands down in any comparison of the energy used up in the manufacture, transport, construction and (eventually) disposal of the product, the concept known as ‘embodied energy'. “Straw's embodied energy is as close to zero as you can get for a building material,” he says. Concrete, he says, has by contrast an appalling embodied energy rating.
Like giant Lego bricks for adults, straw bales pile up satisfyingly quickly. They can also be moulded to shape easily using hand shears, electric hedge trimmers or even chain saws. Amazon Nails, a small women-run straw bale consultancy firm based in west Yorkshire, talk of the inspiration which can come when they initiate non-builders into what they describe as a more common-sense way of building. One of their latest projects has to be to help the Ecology Building Society create a meeting room made of load-bearing straw walls at its head office site near Skipton, a circular building which was erected in part by volunteers from among the society's staff and membership.
But, with memories of big bad wolves with powerful lungs deep in the folk consciousness, is it really sensible to build with straw? Jon Hollely, who was a local authority building inspector for many years before moving to set up his independent company, is reassuring: “It's very tough stuff, straw,” he says. He points to studies in Canada and the US which demonstrate the effectiveness of straw bale building techniques and he adds that straw bale houses have also easily met minimum standards for fire safety in tests.
He does, however, make an important caveat. The workmanship for a straw bale house must be good, he says, and home-owners must be prepared to look after their buildings. Straw houses have an enemy: damp.
If the external lime render begins to crack (and cracks are, in the course of time, almost inevitable), rain can creep inside and get to work on the straw. Kester Wilkinson, who lives with his partner Zinnia and their two children in a straw bale house in Herefordshire which they built themselves, admits to having worries on this score. “Our one big concern is that the straw is rotting somewhere inside. ” he says. Their house, an impressive two-storey construction with four bedrooms and a massive 36 foot x 15 foot living room, is now three years old and seems to be resisting the weather well. Kester points out that windows and doorways are potentially weak spots where damp could find a way in, though he adds, “I can see no evidence of any problems”.
Kester and his family benefit from the great insulation properties of straw, with annual heating bills for their large house well below a hundred pounds. Kester also talks of the ‘lovely atmosphere' which exists inside their straw-built house. “It's quite nice not being hermetically sealed in,” he says.
However, he advises others thinking of following his lead to approach a straw bale self-build project realistically. “I was very caught up with the romance of it all. I thought it would be cheap, and easy, and quick,” he says. Instead, like many other self-builders, he found the experience stressful. “People need to go into it with their eyes open,” he warns.
Perhaps surprisingly, straw bale building is not necessarily much cheaper than conventional building. Wall materials account for only 10-15% of total building costs, so savings here are relatively insignificant in terms of overall expenditure. Straw also needs lime rendering, not plaster, to ensure that any moisture trapped within can be wicked away. Kester and Zinnia Wilkinson estimate that they got through about 400-500 bales at £1.50 each in constructing their house, but then had to spend a further £3000 or so on the lime render.
There can also be on-going difficulties when living in an unorthodox property. “It was difficult to get a mortgage, and it was difficult to get insurance,” Kester says. Insurance is now provided for the Wilkinson's house through NFU, which has the advantage of years of experience of insuring thatched cottages.
For the moment, straw bale building is the preserve of a relatively small band of devotees. But this could be changing. Amazon Nails, for example, are currently working with a Birmingham-based social housing developer which will see two straw bale bungalows built, by a mainstream construction company, next year. In Cornwall, several straw bale extensions to school buildings are under way.
“If you're looking for sustainable options, I've yet to be convinced anything comes close. It's pollution free, and it adds value to farmers' waste products,” Jon Hollely says. But just make sure you can keep the British weather out.
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