Human ingenuity has fashioned shelter out of any materials at hand, including grass and straw.
You might think that the industrial age is beyond straw. But since the 1980s, a handful of people, primarily in the southwest, have been building houses whose walls are made out of straw bales, usually covered with a layer of plaster.
There are approximately 150 new straw-bale houses in the United States and elsewhere, say Athena Swentzell Steen and Bill Steen, co-authors with David Bainbridge and David Eisenberg of “The Straw Bale House” (Chelsea Green, $30).
Also surviving are some houses from the 19th and early 20th centuries, when the building technique was fairly common on the prairies of the Great Plains and not unknown in other parts of the country.
For the uninitiated, straw bales are oversize “bricks” of straw bound by a mechanical baler with wire. They come in various sizes and dimensions, but typically weigh about 50 pounds each.
The Steens and their co-authors, all activists in innovative building techniques and save-the-environment movements, say that these byproducts of grass farming and a rural life have a great deal to offer a modern high-tech society.
For one thing, straw bales provide excellent insulation value for a relatively low cost. For another, they are a readily renewable resource.
“You are using a waste product that otherwise has to be burned, which causes pollution and health hazards, and you aren’t cutting down trees,” says Athena. “Furthermore, the building technique takes no special tools and is easily mastered by anyone who has ever played with Lego blocks. And these houses can be put up in virtually any climate.”
The couple have built their own straw-bale guest house at their home in Canelo, Ariz. They, like others who took up the technique in the 1980s, were after low-cost shelter and a self-sufficient way of life. These days, however, there are also bank-financed houses designed by architects and built by contractors. They are going up in Santa Fe and Seattle and in localities in Arizona, California and Colorado.
What’s different about a straw-bale house is its walls. The floors, roof, electricity, and plumbing are the same as in houses of other materials. To conform to typical building codes, modern straw-bale houses usually have a structural support system of wood, metal, concrete blocks or cement.
“They are most practical when there is a handy supply of straw bales,” says Bill Steen.
The weak link is moisture. If water is allowed to penetrate the interior of the bales, they will rot from the inside out. So it is essential to protect them from direct contact with water, especially from water entering at ground level. But with proper precautions, straw-bale houses can be built in hot, humid areas. One structure erected in Huntsville, Ala., in the 1930s is still standing in good condition.
Other concerns include the fear of fire, insects and allergies.
“The bales are so compressed and compacted that they don’t burn easily,” says Athena. “Where there has been fire, the edges have charred but the whole house has not burned.
“During construction, people with allergies should wear goggles and dust masks. But once the walls are sealed, any allergens or insects in the straw can’t get out.”
What do building officials think?
“You get raised eyebrows from local building officials who aren’t familiar with straw-bale houses,” says Bill. “But I don’t know of anyone who has been turned down after educating the officials.”
The state of New Mexico has been issuing experimental building permits for this type of construction, which means that the building inspector will monitor the construction more closely. New Mexico, Tucson, and Pima County in Arizona are currently developing written standards that would allow straw bales as a permitted nonstructural building material.
Under the auspices of the University of Arizona, the Steens are helping develop a community of 50 straw-bale houses in Sonora, Mexico.
The use of straw in forms other than bales is also under study. Experimental products include panel boards that can be cut and screwed like wood composition board and trusses.
“For us, it’s not the straw that matters,” says Athena Steen. “It’s creating a building with sensitivity which is part of a much bigger picture.”
MEMO: “The Straw Bale House” introduces readers to the theory and practice of straw-bale structures. The Steens conduct weekend workshops on this method of construction; (the next one is May 6-7). For information, contact Bill Steen, The Canelo Project, HC 1 Box 324, Elgin, AZ 85611.