Not the last straw: Homes made from straw bales make a comeback
These homes are incredibly energy efficient, but the cost of building one may prohibit many from owning the eco-friendly abode.
Mon, Jan 11, 2010 at 05:10 AM
RESURGENCE: Straw bale buildings are popular in drier areas such as California, Arizona and Mexico. (Photo: Courtesy Philip Higgs)
After carpenter ants literally ate Philip Higgs’ studio in Boulder, Colo., he decided to rebuild anew — only this time, with straw.
“I wanted to build something that was going to be efficient and use passive solar techniques so that it wouldn’t use a lot of energy,” says Higgs.
Higgs is hardly alone.
Straw has been used as an insulating material for many centuries, and many bale homes built in the 1800s still exist in the U.S. and Europe today. Though building with straw fell out of favor with consumers around the 1920s, straw bale buildings’ popularity has surged in the past 20 years.
The buildings are especially popular in drier areas such as California, Arizona and Mexico. They also can be built in more humid regions, with the proper precautions.
According to straw bale experts, the material is as pest-resistant and waterproof as wood framing. And, contrary to popular belief, straw bales are actually quite fire-resistant due to the tightness of the bales, which keeps out oxygen, a necessary component for fire.
One reason that straw bale buildings are incredibly energy efficient is because of their thick walls and tightly packed bales. One industry Web site claims that a typical straw bale wall is roughly three times as energy efficient as a conventional wall.
Building with straw bales also finds a use for what would otherwise be a waste material. Straw is the inedible stalk from crops like rice, wheat, barley and rye. Because the material doesn’t decompose quickly, farmers can’t simply plow the straw back into the ground, so instead they typically burn it, creating blackened skies and releasing large amounts of carbon dioxide.
“Their waste product becomes food for our industry, so that’s a big advantage,” says Greg VanMechelen, owner of VanMechelen Architects in Berkeley, Calif.
In addition, straw bale buildings provide a good thermal mass due to the thickness of the straw bales and the stucco or plaster that seals them in.
“The buildings store temperature very well, much like the ocean,” explains VanMechelen. “So if you do it right, your house is absorbing heat in the daytime and releasing it at night to keep you warm. At the same time, it’s storing coolness at night and releasing it during the day.”
As a result of their superior thermal mass, it’s easy to keep straw bale buildings within a 5- to 10-degree range through the day and night, all without an additional heating system. In comparison, most conventional houses can fluctuate 20 to 30 degrees through a 24-hour period, so there’s usually a need for additional heating or cooling.
Learn from it
Straw bale buildings are so eco-friendly that some even serve as educational tools for green buildings.
For example, the Shorebird Park Nature Center in Berkeley, Calif., uses its straw bale visitor’s center to educate students, architects and even mayors on the many benefits of building with straw.
“Before we had a straw bale building, we were always talking about how people need to recycle, but we weren’t walking the walk,” says Patricia Donald, coordinator of the center. “The straw building made talking about helping the environment a real thing.”
The nature center even comes with a “truth window,” a small hole in the plaster found in many straw bale buildings that allows people to view the straw behind the wall.
But despite its growing popularity, not everyone is jumping on the straw bale bandwagon just yet. Critics argue that building with straw is not ideal for creating more efficient buildings because it’s just too expensive.
“The only way that green building is going to have a real impact on the marketplace is if it’s affordable,” says Josh Moore, an architect for Quantum Builders Inc. and a certified green building professional. “You’re taking a waste material and you’re using it in a neat way, but if we’re trying to come up with solutions for what could really make a difference and solve problems, straw bale is just not there.”
Though the materials used for straw bale buildings – straw and plaster – are typically inexpensive, the special knowledge required to design and build these structures usually means that labor costs can be anywhere between 10 percent and 20 percent higher than for traditional buildings, though some of that cost is made back through energy efficiency.
“The construction of these buildings takes a person who’s done tons of training to really understand exactly how to get the material to behave,” says Moore. “It just ends up costing the consumer too much money for the benefit it produces.”
In addition, straw bales can create extra hassle in terms of coordinating their delivery from local farmers, having a big enough job site to store all the bales and keeping them dry during construction.
One way that people help keep labor costs down is to throw “bale raising” parties where friends and family members help stack bales and plaster walls.
“My contractor and I built the foundation wall, but then I had a big bale stacking weekend where I had a lot of friends who were really interested in the whole thing that came out to help, especially the first day,” says Higgs, who built the straw bale studio in Colorado. “The cool thing about it is that people would walk past and stop and ask questions about it. It’s sort of evangelical in that way. You get into some really long conversations.”
The community building aspect also appeals to Dan Smith, owner of Daniel Smith and Associates, a green architecture firm in Berkeley, Calif. Over the past decade, Smith has built about 40 straw bale homes, even one off the coast of Ireland.
“I think it’s great because building one’s own house is a traditional American archetype that’s sort of fallen by the wayside,” says Smith. “It’s a very rewarding process and it creates a lot of good community spirit.”
But perhaps the most appealing aspect of straw bale buildings is found inside the building itself.
Owners of straw bale homes often speak of the “coziness factor” created by the super-thick bales and the curviness of the walls. Though it’s not necessarily an eco-friendly aspect, the walls give off a sense of security while also providing excellent sound insulation – a big plus for urban areas.
“The attitude and feel of the building is very calm and quiet. You can’t hear anything,” says Higgs of his studio. “It’s kind of like being in a cathedral-style church; there’s a sort of quiet feel to it. You just want to sit in there and play records all day.”
Photos: Courtesy Philip Higgs
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