Nestled amongst the moss-covered maples of Vashon Island is a small cottage that exudes old-world charm. The whitewashed walls and pitched, metal roof invite all who come across it to enter. An onlooker wouldn’t know that this house’s walls are made of compacted agricultural byproduct called straw bales.
It looks like a modern, stucco home, but there is one thing that gives its structure away. The bloated window ledges covered in art are about 15 inches wide because of the width of the straw bales behind the plaster.
Below exposed wooden rafters is a reclaimed hardwood floor. The pot-bellied woodstove in the middle of the living room can easily warm the 1340-square-foot, one-bedroom home.
And for $578,500, this little gem and its 2.3 acres can be yours. But there is more to it than romance. This home offers a chance to live green.
Straw-bale construction can reduce lumber usage, increase insulation efficiency, reduce pollutants emitted into the atmosphere and offer a unique structural design.
Architect Terry Phelan, owner of Living Shelter Design in Issaquah, Wash., started her business as a conventional architecture firm. A few years after it opened, she read an environmental publication about green design and had an "Aha" moment.
"I’d been an environmentalist for years, but I was designing these houses that were bad for the planet," Phelan said.
It felt like a dichotomy of interests, she said, so she decided to learn as much about green building as she could. She was especially interested in straw-bale, and focused her business on the design of eco-friendly homes. Since then, she has designed several straw-bale homes. This includes a three-story home in Carnation, Wash. It was the first of its kind to be built in King County.
Building walls with these bales can reduce lumber use up to 50 percent. In an average, single-family home, that is a reduction of about 16,000 board feet, the same amount of board feet found in 32 Douglas Firs, totaling $5000 worth of raw lumber, according to David Wallin, an environmental science professor at Western Washington University.
In the United States, 200 million tons of straw is either burned or left to decompose on its own annually, according to Strawbale.com.
Rather than let this straw go to waste, a straw-bale home uses it for housing. The home is built using the straw bales stacked like giant bricks, tied together by twine and then covered with plaster. Bamboo or rebar runs through the bales and into the foundation, holding the structure in place. The walls go up quickly, but tying them together is a bit tedious. The tool used to pull the twine through the bales looks like a very large needle. The finished product resembles adobe houses of the Southwest.
The first of these straw-bale homes were built in Nebraska at the turn of the 20th century because wood was a scarce resource while the grasses of the Great Plains were plentiful. Some of these original 100-year-old homes still stand, which is a testament to their longevity, Phelan said. The plaster on some of these old houses has been peeled back to see how the straw has survived, and the straw still shines as golden as the day it was harvested. By plastering the outside of the straw bales, oxygen and water are unable to touch the straw, which prevents decomposition, Phelan said.
"A straw bale is denser than a phone book," Phelan said, "Which means it won’t burn easily, and there are no cavities for rodents to occupy."
The insulation value of a straw-bale wall is triple that of a conventional wall. This means a much lower heating and cooling bill because the warm stays in, and with the help of the plaster coating, the cool stays out.
Bryan Jones is a civil engineer with Jones Engineers in Bellingham, Wash. He said straw-bale homes are not only feasible in the Northwest, but they’re already being built. However, many people are skeptical about the quality and durability of a straw-bale structure. Jones said they have reason to be skeptical if the homeowner is unwilling to perform regular moisture checks and fill cracks in the plaster. Not taking care of the home means the structure will start to rot and create crevices for pests and water problems.
"If you don’t take care of it, you’ll be miserable and never sell it, but if you take care of it, why not?" Jones said.
Finding an insurer and financial backing, as well as getting the permits necessary to build, can often be the most challenging part of straw-bale construction. State Farm Insurance won’t insure straw-bale structures because there has not been enough testing done on the buildings, according to company policy.
Companies often cite flammability as the main reason they cannot back the building. In reality, the density and high silica content of the straw-bales make the walls less likely to catch fire, Phelan said. They will smolder, but they won’t burn easily.
Bill Jevney and his wife Juanita Ramsey-Jevney took out a personal loan on their home to finance a private primary school built out of straw bales in Sequim, Wash. Five Acre School is insured through an insurer that covers all private schools in Washington State. They built the school because the environmental benefits and energy savings made sense, Jevney said. Five Acre School was built in 1994 as a 2000-square-foot, one-room schoolhouse and was expanded nine years ago to 4000 square feet. Electric heat is used to warm the school, and Jevney estimates that it costs $200 per month to heat the structure in the winter.
The interior of the school looks normal, cluttered with toys, a small computer lab and a music room. White boards and cubbies hang from the walls. Outlets on the exterior wall are connected to insulated electrical wires that run through the bales of straw. This is how all exterior electrical is handled. The plywood floor and tile ceiling are more traditional. To simplify plumbing, the bathroom is in the center of the building so fewer pipes run through the straw.
The L-shaped school creates an exterior nook where students have painted a mural of fictitious characters in a forest. One of the painted trees has a small plate of glass in its center. Spiky, golden straw shines behind the "Window of Truth," giving away the mass hidden behind the plaster.
This plaster plays a vital role in structural soundness in an earthquake. Phelan said straw-bale structures are much more flexible than stud-framed homes, so rather than breaking, the bales are held together by the plaster and move with the tremors.
"It’s not going to slump if it’s designed well," Phelan said.
Phelan usually teaches classes on straw-bale design in the summer.
"One of the things I’ve found is people feel so empowered by realizing this is something they could do themselves," Phelan said.
Depending on the type of straw, a bale costs around $3 per bale and weighs about 60 pounds. They’re usually for sale at farm or pet supply stores or online, but Phelan said it is best to inspect them in person to ensure quality. A good straw bale for home building is tightly compacted with straight sides.
Phelan said she has learned several lessons about designing straw-bale homes. One thing she recommends, especially in the Pacific Northwest where rain bears down on these moisture-sensitive shelters, is to build roof overhangs carefully. Moisture sensors are also installed into the wall so that homeowners can be sure their walls aren’t leaking.
Sometimes people approach Phelan looking for a maintenance-free house, and she said she tells them there is no such thing. For a straw-bale home, moisture checks, plaster patching, and overall home care needs to be maintained, but the upkeep is easy to do. However, if the owner were to abandon the home, the walls would eventually biodegrade.
"It’s a compostable house, but it won’t compost until you’re ready, or at least until you stop caring for it," Phelan said.
In the meantime, one little eco-friendly home on Vashon Island waits for a new patron, not yet ready to be returned back to the earth.
Anne Maertens studies environmental journalism. This is her first published piece.