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The quake-proof house made of straw

  • Story Highlights
  • Straw bales can be used in construction instead of brick or plywood
  • In earthquakes, straw houses are safer and more stable than brick
  • Straw homes require more labor, but materials are inexpensive
  • Thick straw walls provide insulation all year round
  • Next Article in Technology »
By Linnie Rawlinson for CNN
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LONDON, England (CNN) -- When artist Gordon Smedt began planning his Mediterranean-style home in California's Santa Cruz mountains, little did he expect that his finished dwelling would consist, in the main part, of straw.

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Gordon Smedt's Mediterranean-style home in Santa Cruz, California, is made from straw bales

"At first I thought it was kind of a joke," he told CNN. "But I did more reading on it and I liked what it did environmentally, using a renewable resource."

Far from leaving him vulnerable to the Big Bad Wolf, Smedt's 'straw-bale' home protects him and his family from cold winter nights, the hot summer sun -- and even from earthquakes.

Smedt started looking at alternative construction methods after his honeymoon in Europe, where he and his wife were drawn to the architecture there. "All the older homes in Europe that were masonry-built had these beautiful, deep-set windows," he told CNN.

For Smedt, 'straw-bale construction' - the technique of building houses from bales of straw that gives thick walls and a rustic feel - seemed like a perfect alternative.

'Lego-like playfulness'

Smedt sought the assistance of Californian architect Dan Smith, who built his first straw bale house in 1994.

Smith was first drawn to the method as a way of making thicker walls without using brick, which can be hazardous in earthquake country. "It was so hard to make conventional construction softer, thicker or more handmade looking," he told CNN. "But it's very hard to get [straw bales] flat -- it's inherently a little bit more lumpy and natural." Photo See examples of straw bale houses »

Smith is also a fan of the material's "Lego-like playfulness" and handmade look. "People can imagine stacking them up," he explained.

That attracts those who fancy making the shift from plastic building blocks to homespun construction. Parts of the build, like putting up the walls, are an excuse to invite friends and family over to help.

"The bale-raising remains one of the high points because it always turns into a party or a get-together over a weekend," said Smith.

Once in place, the bales are given a reinforced skin made of heavy wire mesh attached to a wood frame. The walls are then plastered with lime, cement or an earthen plaster, depending on the site's environment. The finished structure has walls that are two feet deep -- and this depth gives the building's designers the opportunity to create tailored built-in features.

Comfort and security

For Gordon Smedt, that was one of straw bale construction's main attractions. "Every opening, door, window -- you have an excuse to get creative and make it an element," he told CNN.

Rather than hanging kitchen cabinets, Smedt cut niches into the walls to make built-in shelves, while architects Dan Smith and Dietmar Lorenz designed the space to show off Smedt's artwork.

The thick walls also create a feeling of comfort and security, Smedt says, muffling external sounds and providing insulation. But one of the most remarkable aspects of the house is its thermal mass: the straw bales have allowed Smedt to slash his energy bills.

"I will never need air conditioning in this house," he stated. "Last summer we had temperatures of over 100 degrees for over a week. The house never got above 79, 80 degrees inside."

And in winter time, the thick walls keep the house cozy. "All the plaster and stucco in the house absorbs solar heat during the day and then slowly releases it back at night," Smedt explained.

Renewable resource

Straw bales were first used in construction in the early 20th century in Sandhills, Nebraska, where timber was scarce. The practice was revived in the 1970's and 1980's with the rise of the green movement.

Larger straw-bale-constructed buildings are now being designed with an emphasis on environmental sustainability.

Dan Smith's firm has recently completed the LEED-Gold-certified Presentation Center Dining Hall, an interfaith retreat and conference center, also in the Santa Cruz mountains.

"We were able to incorporate living roofs, straw bale construction and cellulose on the ceilings, recycled newspaper for the insulation and solar-heated water for the dishwashing," Smith said.

Suited for earthquake country

As a method of construction, straw bales have also been seized upon in earthquake-prone countries like Pakistan, Mongolia and China, as Smith explains: "It's a wonderful alternative to these brick and rubble-wall death-traps in earthquake country."

"It's not only strong but it's fairly ductile and it's not brittle," he continued. "It can keep on absorbing energy. Even after the skin starts cracking, the bales have a reserve capacity, so it would be very hard for it to totally collapse." In earthquake simulation tests, straw bale walls have been shown to absorb as much energy as plywood walls without breaking up.

Although care has to be taken during construction -- stray wisps and soldering torches are a dangerous mix -- Smith maintains his finished homes are surprisingly fire resistant.

"That's partly down to the inch-and-a-half thick cement skin, and partly down to the density of the bales," he said. "The bale inside is like a phone book: it's very dense and so it doesn't actually support combustion."

Tailored to the local environment

But what of the drawbacks? Smith is upfront about the main challenge of straw bale homes -- at least in the West. "It is more expensive in the developed economy where labor is expensive," he told CNN. "There's more handwork, and that's part of the charm of it. In places like Pakistan and Mongolia, it's very affordable because labor is inexpensive."

In wetter climates, it's also a challenge to ensure the bales stay dry. "You have to think about where the rain coming from and you have to make sure there's protection," Smith explained. "It does fine as long as it doesn't get too wet or moist."

So Smith tailors the plaster skin and the design to suit the local environment, from earth plaster in New Mexico to heavy lime plaster in Ireland.

Part of the fun of straw bale construction is that people are still working out how to do it, according to Smith. And he thinks the method has a strong future in a society where energy and building materials become increasingly precious. He believes others will continue to develop innovative ways of using straw and similar resources like hemp.

But for now, Gordon Smedt is happy with his quiet, green, tailored home and art space. "There's not much I would change in the house at all," he told CNN. "Although I'm sure, over time, I'll think of something."

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For more information on Dan Smith and Associates, visit www.dsaarch.com. E-mail to a friend E-mail to a friend

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