How not to build a straw house

THE English-speaking world does not look kindly on straw. Grasping at straws, straw-man arguments, the last straws and the straws that break so many camels' backs all attest to that. There is also the cautionary tale that straw is the worst material from which to build a house, particularly if you are a pig with a hungry wolf around. So the cards were stacked against Warren Brush, the director of a not-for-profit farm in Cuyama, California, when local officials learned in 2006 that he had several buildings made of straw bales on his land.

They have tried to fine him. A lot. But the case is still unresolved. The problem is that California's building codes make no provision for the use of straw. And Mr Brush has many defenders—among them several university scientists and David Eisenberg, the chairman of the United States Green Building Council's code committee. They would like to see the prejudice against straw houses eliminated, for straw is, in many ways, an ideal building material.

It is, for one thing, a great insulator. That keeps down the heating bills in houses made from it. It is also a waste product that would otherwise be burned, and is therefore cheap. And—very much to the point in a place like California—it is earthquake-resistant. Last year a test conducted at the University of Nevada's large-scale structures laboratory showed that straw-bale constructions could withstand twice the amount of ground motion recorded in the Northridge earthquake that hit Los Angeles in 1994. Mr Brush's ranch is a mere 18km (11 miles) from the San Andreas Fault. Instead of prosecuting him, his supporters argue, the state should be installing seismic sensors on his ranch to see what happens if and when there is an earthquake there.

Modern straw buildings start with a foundation of gravel held in the kind of plastic bags used for vegetables at a grocery store, and covered with a soil mortar. The walls are made of tightly packed straw bales held together with bamboo pins and covered with fishing nets. These are then coated with a clay-based plaster. Aesthetically, the final product is similar to stucco or adobe, but because its components—clay, gravel, straw and netting—are more flexible than brick, concrete or steel, it is much more ductile and thus better able to absorb seismic energy.

California, of course, is already thoroughly earthquake-proofed. But straw buildings might do well in seismically active places that are less wealthy. After an earthquake devastated Pakistan in 2005, Darcey Donovan, a structural engineer from Truckee, California, set up a not-for-profit straw-bale-construction operation that has since built 17 houses there. She has been designing straw-bale houses in California for ten years and lives in one that she and her husband built in 2007. It has two floors, three bedrooms, two bathrooms and a two-car garage.

There are, as it were, other straws in the wind: a post office in suburban Albuquerque, a Quaker school in Maryland, an office complex in suburban Los Angeles and an urban-renewal project in Binghamton, New York, have all been built from straw. Even California is having a rethink, and may change its rules to accommodate straw-bale construction. As Mr Eisenberg observes, “the lesson of the Three Little Pigs isn't to avoid straw. It's that you don't let a pig build your house.”