If there is one thing that fairy tales tell us about civil engineering, it is not to build anything using dried-out stalks of grain. This is the First Little Pig’s Law of Construction: violate it, and a strong wind or heavy-breathing wolf will come along, and whoosh! You’re standing on a bare slab.

Despite this warning, a few people in the Washington area have been building things—walls, homes and even a school —out of straw.

Such structures have straw instead of drywall and insulation, with dozens of bales stacked around the building’s wood-and-metal skeletons. The bales are coated in hardened plaster, which keeps out water and fire and gives buildings a stucco look.

Some designers say straw is ideal for ‘green’ building because it recycles farm waste and saves energy by keeping interiors cool. Last week, as workers were completing projects at a city building in Bowie, Md, and a school in College Park, Md., straw-bale fans said the “Three Little Pigs” story had the whole thing wrong.

As unusual as they sound, straw buildings aren’t a new idea. In the late 1800s, people in a particularly treeless corner of Nebraska began using straw and hay to make the prairie equivalent of an igloo: they stacked up bales and slapped on a roof. Now, straw seems to be finding a new niche, nationally and locally. The International Straw Bale Building Registry lists 538 projects nationwide, but the site says that might be a low estimate.

“I have clients walk in and say: I want your house,“ said Bill Hutchins, a Takoma Park, Md, architect, who used bales in an addition to his century-old bungalow. Hutchins painted the thick, adobe-like walls in dreamy earth tones and accented the house with natural wood, for a kind of hobbits-in-Santa Fe look.

 Hutchins said he has built four projects in the mid-Atlantic with straw and has six on the drawing board. The reason for the resurgence in straw construction is not a scarcity of lumber. Instead, the appeal comes from the material’s environmental credentials.

The green building movement has adopted “green roofs” which have plants that absorb storm runoff, and toilets that compost waste instead of flushing it. In straw-bale projects, the change is in a building’s bones.

The straw that’s used is a kind of farm leftover, the stalks left behind when such grains as wheat are harvested.

Unlike hay, which is a different crop grown for animal feed, straw is used primarily for animal bedding. Usually, straw-bale builders say, there’s more of it than anyone needs. “The new building is part of a maintenance complex that will have several green features, including roof gardens and tubes that funnel sunlight into interior spaces. One part of the building is being made with straw; regular sheet metal is being used for the rest.

Friends Community School, which has 165 students in kindergarten through eighth grade, took an even bolder approach. The building’s outside walls were filled in with straw bales used as insulation.

Connie Belfiore, the school’s interim leader, said green building fit the Quaker campus’ focus on protecting the environment. And the walls, which are about 22 inches thick after the plaster is applied, will save money on heating and air conditioning.

But it’s one thing to know all that and another to accept that your building is really being stuffed with straw. Even fans of straw say it has drawbacks as a building material.

The thick walls take up a lot of space, and some projects won’t fit on small lots. Because of the labour involved, a straw-bale wall can cost twice as much as a regular one, although some homeowners save money by doing some work themselves.

And it can take time to convince building officials that a straw building meets code.Then there are the cracks in the plaster. In some cases, homeowners have to seal them before rain or rodents get in. If moisture is trapped in the straw ... well, that’s bad. “Then your walls will turn to compost,” Hutchins said.

But straw builders say their structures are just as sturdy and fire-resistant as more conventional ones. In fact, they say, people really ought to be worried about places filled with such insubstantial materials as fiberglass and drywall.

LA Times-Washington Post