Poor engineering and a particularly nasty wolf may have doomed Three Little Pigs and their straw house, but modern-day straw-bale buildings are holding their own against the elements.

Straw-bale construction harkens back more than a century.

Settlers arriving in Nebraska found the area lacking in wood, so they looked for other natural materials to build lodging. In doing so, they discovered that straw from their fields, compressed tightly into bales and then stacked and sealed with clay from local rivers, provided ample protection from the worst prairie weather.

Over time, the straw bales gave way to newer technologies. However, rising environmental consciousness has brought an old practice back to life.

Photos courtesy of Building Alternatives
Crew works on the first Winnipeg straw home under permit, above, and the finished product.

Today's version is an earthy mix of straw covered with one to two inches of a greyish stucco-like plaster. Because the straw bale and plaster combination is extremely heavy and thick, is used only for the sides, and other, more lightweight and environmentally friendly insulation is used for roofs.

The overall look - mildly Mediterranean with monotone, greyish walls - can be adapted as wildly as the whim of a designer's creativity allows.

Several hundred straw-bale buildings have been built across Canada since the mid-1980s.

Chris Magwood, a Peterborough, Ont., contractor who teaches a course on sustainable building at Sir Sanford Fleming College and is active with the Ontario Straw Bale Building Coalition (OSBBC), estimates there are at least 500 straw-bale buildings in Canada, including homes and cottages as well as agricultural and other commercial structures.

Proponents have banded together, creating industry associations, developing courses for builders and holding conferences to share best practices and discuss issues as wide-ranging as business strategies and building codes.

Magwood says straw offers esthetic and environmental benefits. "We're taking a waste, a leftover agricultural product, and turning it into a super-insulated building. It helps the building use way less energy over its lifetime than a conventional building."

While straw-bale construction is predominantly a cottage industry, satisfying a relatively modest, eco-conscious niche, mainstream circles are starting to pay attention.

Magwood says that, in the mid-1990s, the U.S. Department of Energy compared a bale house and a frame house, built adjacent to each other and to the same plan, and found the straw one used 60 per cent less energy for heating. He adds that other studies using computer modelling report 25-75 per cent in energy savings.

Straw bale has also caught the eye of the Canada Mortgage and Housing Corp., but for a different reason.

Don Fugler, a senior researcher with CMHC, says the federal Crown agency received requests for mortgage insurance on straw-bale homes, but lacked information about them.

"We initiated a number of relatively small research projects to try and scope out our answer," Fugler says, describing how computer simulations helped CMHC determine that straw-bale houses can indeed save energy and that potential hazards could be avoided by employing proper building procedures.

"We have found through our moisture studies that you should not put straw below grade or under moisture stress. When you do things properly, the straw seems to be doing fine inside the wall."

The risk of fire is also minimal. "The only straw-bale fire issues I've heard about were on construction sites with loose straw around," Fugler says. "Once you envelop the bales with plaster or stucco, they're far better than a wall filled with a fibrous insulation."

Kris Dick, an adjunct professor of biosystems engineering at the University of Manitoba and a principal with Building Alternatives, which specializes in engineering and structural design for all kinds of buildings, agrees.

"A stuccoed straw-bale wall has a two-hour fire rating. That's basically equivalent to commercial construction," Dick says, adding that a wood-frame residential house typically has a 45-minute rating.

"You have a one-to two-inch stucco skin on both sides. You need air and a fuel source to be able to burn, but the fire can't get through the stucco into the bale."

Dick and his associates have built a 4,200-sq.-ft. research facility on campus.

The straw-bale building is rigged with monitors to check temperature, moisture and structural loads from wind and snow.

"It's an ongoing research project," Dick says, noting that straw bale and conventional structures have much in common.

"You can have the same kind of problems with a conventional building as you would with straw.

"You have to pay good attention to your building envelope, placing flashing around windows, keeping moisture away from walls and having appropriate overhangs."

Habib John Gonzales, a builder with Sustainable Works in Crescent Valley, B.C., has worked on roughly 100 projects over the past decade.

He says use of straw bale is growing slowly and steadily in popularity, but he sees significant activity that strikes him as too experimental.

He warns, for instance, that a trend toward large picture windows negates many of the energy savings achieved through straw, and that many natural, least-processed materials such as earth-based plasters can lead to complications because they cure slowly and wear rapidly.

"The industry has many mature practitioners, but some people are into the fringe and off to the side, where it's more playful, arts-and-craftsy and experimental. I would like to see a little more sobriety and professionalism with some of the innovations."

Michael Gray, engineering environmental services officer with Canadian Forces Base Suffield in Alberta, says he's developing plans for a 3,600-sq.-ft. straw-bale building and is leaning toward materials that are considered tried and true, including prefabricated walls that are relatively easy to install.

"I'll be sticking with materials that we know even though it might not be the leading environmental edge," says Gray, who attended an international straw-bale conference staged by the OSBBC in September in order to learn about the technology.

He says the building will house computer and telecommunications workshops, and he is looking at measures such as passive solar in order to maximize energy efficiency.

"I definitely think this has the potential to catch on," Gray says. "Both the government in general and (the Department of) National Defence do a lot of construction, and I am hoping we'll consider this as a viable option for future buildings."

If anything takes straw-bale buildings mainstream, says the OSBBC's Magwood, it will be ready access to prefabricated straw-bale wall panels, such as those Gray plans to use.

"It would make sense to mainstream builders because it's like any drop-and-attach kind of wall system. It's also quite a bit less expensive, so I can see a larger market going in that direction."

Ultimately, Magwood sees energy and the environment as short-term drivers. "As energy and fuel prices go up, the idea that you can build a house that will take half as much to heat and cool will start to appeal more and more to mainstream buyers."

(Saul Chernos can be reached at chernos@businessedge.ca)