Spinning Straw into Gold: Straw Bale HousesOctober 9, 2009
The Three Little Pigs got it all wrong! Turns out that it was the straw house – not the one of sticks or the one of bricks – that could stand up to all that huffing and puffing. Not only do straw bale houses provide excellent insulation from wind and extremes of temperature, they’re also proving to be surprisingly stable in earthquake country.
That’s one of the curious facts I learned from Jack Ruskey, one of the co-founders of Oryzatech, a start-up that was showing its wares at the recent West Coast Green building conference. Ruskey, a retired lawyer, grins and says that the day back in 2001, when Oryzatech won a $300,000 grant from the California Department of Food and Agriculture, was one of the worst days of his life.
Ruskey’s a folksy kind of guy with a laid-back country style that’s common to several straw bale builders I have met. His bio says that he’s a farmer as well as a retired attorney, so I suspect that this bluff statement is just his way of joshing with the city girl. I take it to mean that the grant opened to door to veritable haystack of work, and closed it on any notion of restful retirement that Ruskey might have been entertaining. For the past nine years, Ruskey and his colleagues have been up to their collective armpits in research about the effectiveness of the funny-looking straw bale block you see here. That research has resulted in the company winning the first US patent protection for Oryzatech’s bale-making advance.
It also turns out the Three Little Pigs story was both right and wrong in saying that the reason the first pig built the straw house was that “it was the easiest thing to do.” Straw houses are easy to construct. The hard part comes when it’s time to invite the building inspector over for a look-see (more about that later, though).
On his fun and informative Straw Bale Trail website, David Bainbridge, a prof who teaches sustainability at the Marshall Goldsmith School of Management in San Diego, notes that straw bale buildings are “are friendly to build… Families can work together and even small children can participate.”
“People like these buildings because they are very quiet, fire resistant, energy efficient, strong, durable and attractive,” says David. Another folksy guy, Bainbridge is a friend and colleague of mine at Alliant International University. A founding member of CASBA, the California Straw Building Association, David has been building straw bale houses for many years. He has built them all over the world, including in earthquake-prone China. (Not coincidentally, David is a member of the National Earthquake Hazard Reduction Program Coalition.)
Straw bale houses have a true-blue American heritage. They were born on the treeless plains of Nebraska in the 1800′s, but they now are being built around the world, springing up from France and Germany to Australia, Iraq, Russia, Saudi Arabia, and Israel. They’ve spread fast because they can be built cheaply, for just about $2 per square foot. What’s more, they make use of resources that renew quickly (grains grow in a single season whereas trees take decades), and they reuse material that would otherwise have to be managed as waste.
Straw is what’s left after a grain, such as wheat and rice, has been harvested. Oryzatech’s Stak Blocks, for example, are made from rice straw. The company’s odd name comes from the Greek word “oryza” meaning rice.
Before straw bundles can be stacked to make walls, the straw must be compressed into bales. At West Coast Green, Ruskey showed me how the inside of one of Orzyatech’s Stak Bloks looks. It’s not at all what I would have expected. Instead of looking like a bale of hay, the block looks and feels like the surface of a plywood sheet. It’s surprisingly dense, almost like a piece of wood cut across the grain. Oryzatech makes the block using what it calls a “scalable, low-energy production process.” That means that they do more than stomp on the straw, but the process is proprietary and Ruskey wasn’t talking about it. He did say that the blocks have undergone extensive, independent testing at California Polytechnic University, and test results show that Stak Blocks offer more than three times the thermal value of an insulated 2×6 stud wall. In addition, in an earthquake, they perform better than either wood framing or brittle concrete walls.
Straw bales are usually laid in straight runs, like big bricks. But they can also be bent to create curves and interesting forms. Walls are usually wire meshed or pinned together; Orzyatech has designed a whole system of connectors. Once the bales are stacked, they are often plastered with lime, earth, or cement plasters. The results can be surprisingly beautiful.
Green Benefits of Straw Bale Buildings
David Bainbridge recently joined builder Ken Haggard in publishing a research paper that quantifies the huge impact that straw bale building can make in reducing global warming by “sequestering” carbon. In the newsletter of CASBA, a California non-profit organization whose members are designers, contractors, owner-builders, and people interested in straw building, Bainbridge and Haggard report that carbon can be safely locked up in straw bale buildings for far less than it costs to otherwise dispose of waste straw. Dumping straw bales at sea, for example, would cost around $340 per ton!
Bainbridge and Haggard report that in the US, more than 100 million tons of straw a year could be used to build homes. Because the straw in each house would lock up 40 tons of carbon, those houses could capture and annually sequester up to 40 million tons of carbon across the nation. Moreover, each house could reduce CO2 emissions by 500 to 1000 tons over its lifetime.
In addition, Bainbridge and Haggard note that increased straw bale construction will reduce field burning of straw, in turn reducing the production of global-warming gases and reducing smoke-related health costs.
How to Spin Straw into Gold
When you factor in the energy savings that owners get from their straw bale houses, it begins to look as though the advocates of straw bale house have indeed found a way to spin straw into gold. Bainbridge’s research shows that well-designed straw bale buildings — that optimize, shape, insulation, thermal mass, ventilation, shade and orientation toward the sun to take advantage of solar heating and climatic cooling — owners can cut energy demand dramatically.
The Congregation Beth David Synagogue in San Luis Obispo, for example, reduced its energy use 82%! Near cold, snowy Aspen, Colorado, there’s a 6,000 square foot Waldorf School on the Roaring Fork that was built on time and under budget by volunteers and contractors. A passive solar, daylit building, this straw bale building has reduced heating costs by 60% for the school.
Other contemporary, energy-saving, commercial straw bale buildings here in California include the Real Goods Solar Living Center in Hopland, the Schwaesdall Winery visitor’s center in Ramona, and the Woken Center at Hidden Villa in Los Altos.
There are also high-end, architecturally designed straw bale houses being built by specialty firms; given all the classy interior features, costs run up to $200 a square foot. You can find haute couture urban homes in places like Oakland, California and Washington DC, as well as striking do-it-yourself projects out in rural areas of Arizona and Texas.
One of the most engaging of the do-it-yourself projects is the home of Carolyn Roberts, who wrote about being “a petite, forty-something single Mom with two teenage sons” who found herself unemployed and in need of a place to live. Roberts has written A House of Straw, a book about her journey to bring her life into line with her green values. On her website, Roberts says that although she dreamed of a simple house in harmony with nature, she had “no carpentry experience, no directly relevant skills… no time, no money, no experience…” Nonetheless, she managed to erect “an incredibly sturdy, beautiful and well-insulated house that will last for many years.” Not counting the land, her house cost only $50,000 to build.
“I’ll Huff and I’ll Puff”
To finish it, however, Roberts had to pass 23 county inspections! That astonishing number points up the other big reason the story of the Three Little Pigs was wrong about straw building being the “easiest thing to do.” Two of the major hurdles that straw bale builders have faced have been: 1) building codes that have been developed for other, dissimilar materials and technology, and 2) officials who may be thoroughly versed in the codes and regulations, but who have no background in straw bale building.
Bainbridge says that although “a few people have been discouraged and given up, sustainability and straw bale enthusiasts are a determined lot.” They have put nearly as much effort into educating building inspectors and code staffers as they have into building houses. Straw bale advocate David Eisenberg gave a big push to the much-needed education process when he wrote a series of columns for ‘Building Codes for a Small Planet“, a magazine read by code officials. The two Davids, Bainbridge and Eisenberg, also teamed up to offer a continuing education program for building code officials a few years ago.
“Thanks to the work of hundreds of unnamed builders, to early work by Matts Myhrman and Judy Knox, and The Last Straw magazine, the codes have rarely been a stopper,” says Bainbridge. “The straw bale building response to codes has been helped along by many people – and thanks to all of them – but David Eisenberg, the founder of DCAT (Development Center for Appropriate Technology) and a former builder, and Bruce King, an engineer, have both been instrumental.”
Bainbridge adds, “Several code officials quickly saw the value of straw bale building; they aided the process and provided support by talking to other jurisdictions and code organizations. Building code officials with a farm background usually saw it right away.”
- A House of Straw, Carolyn Robert’s website
- California Straw Building Association (CASBA)
- Developmental Center for Appropriate Technology (DCAT)
- The Last Straw magazine
- Haute Nature blog – straw bale houses and other items of high eco style
- Natural Home Magazine – The Tallest Little Straw Bale in Texas
- New York Times article on Quake Resistance of Straw Bale Houses
- The Straw Bale House, book by David Bainbridge, Athena Steen & Bill Steen (Greenbooks online store)
- Oakland’s Straw Bale House goes on Sale - San Francisco Chronicle
- Registry of straw bale houses around the world (Green Builder)
- Straw Bale bibliography – extensive! – from David Bainbridge
- The Straw Bale Trail website by David Bainbridge