Straw House Survives the Test of Hurricane-force Winds
by Bonnie Alter, London
Images from balehausatbath
We all remember the three little pigs: I'll huff and I'll puff and I'll blow your house in. Well not this one. Built out of straw bales, it has been proven strong enough to withstand hurricane-force winds. When blasted with the equivalent of 120 mph winds, it only moved one sixth of an inch.
That's good enough for a housing co-operative in Leeds; they are looking for planning permission to build 20 of these straw houses. As well as being completely environmental, they look pretty modern and sleek. More after the fold on how they are built.
The houses are part of a project by the University of Bath's Centre for Innovative Construction Materials. They have been carrying out a major research project for the past two years to scientifically assess the performance of straw as a sustainable building material. The two-storey house was opened last year and since then the group has been monitoring it for sustainability in a number of different areas such as insulating properties, humidity levels, air tightness and sound insulation qualities.
Prefab wood panels filled with the straw bales formed the frame of the house. Called Modcell, it's a wall and roof cladding system that uses straw bale and hemp. The walls are about a foot and a half thick. The team discovered that the heating bills were 80% lower than for houses made of bricks due to the high insulating properties of the panels. Construction had a much lower carbon footprint because of the ease of transport.
Straw and hemp are the ultimate environmentally-friendly building materials because they are totally renewable. Straw absorbs carbon dioxide as it grows, so the buildings made from it can have a small, or even negative, carbon footprint. It is a by-product of farming and can be grown locally in many places.
The house has passed fire tests. It was exposed to temperatures over 1000°C and had to withstand the heat for more than half an hour. After two hours the panel still was intact. In the case of a flood the straw can be replaced in the panels at minimal cost. In the Centre's view the house could last more than a hundred years.
A housing co-op is planning to built 20 of them in Leeds. The price of a single storey flat will be £60,000 ($US 86.000 ) and a 4 bedroom row house will be £160,000 ($US 230,000).
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