Back to Basics
By Tom Cruickshank
"Like other homeowners, we love that our house is our personal sanctuary," Ann Baird says. "But we also get satisfaction knowing that we're building and living in a sustainable manner."
"We learned ways to make cob better," Ann says. "We added some pumice to make the mixture stronger and to improve its thermal performance."
How can a home that seems to nod to the Flintstones be so modern? By using cob, a humble mix of earth, sand, and straw. The material has found a niche among the eco-minded, particularly in Britain and, more recently, in the balmy reaches of the Pacific Northwest. There, its hand-built rusticity has lent itself to funky garden sheds and summer cabins, but rarely has it been used for a year-round dwelling.
In 2007, Ann and Gord Baird decided it was time to show what cob is really capable of. On eight hilltop acres just north of Victoria on British Columbia's Vancouver Island, they built a 2,150-square-foot abode, large enough for them and their two kids as well as Ann's parents. They designed it themselves and built it with their own hands to exacting energy standards. Their efforts have garnered lots of praise, and even mainstream engineers and builders have come to see the house for themselves. In October, the Seattle-based International Living Building Institute recognized the Bairds' house for achieving four of its six stringent standards for "living buildings."
Mixed on-site with water to a wet-cookie-dough consistency, cob is easy to work with. "No stick frame, no cranes, no fuss," Gord says. "You simply pack and pile the cob, layer by layer, into free-form walls and leave them to dry." As they mastered the technique and picked up the pace, he and Ann could mix three batches of cob and build a 25-foot section, 2 feet high by up to 2 inches thick, in a single day. To bring the building to engineering and seismic standards, the walls were reinforced with tension cables.
The Bairds say cob's best assets include ecofriendliness, affordability, acoustics, and air quality (there's no paint, particleboard, or vinyl to emit fumes). But the couple had an additional goal. "We're aiming for 'net zero,'" Ann says, referring to their attempt to provide all their energy and water on-site while producing no measurable waste. To that end, solar panels generate their electricity and solar thermal-evacuated tubes their heat. (Air is removed from the tubes to eliminate heat loss through convection and radiation.) The house is equipped with composting toilets, and irrigation water is harvested from the roof. But those green innovations seem almost ordinary compared with the unconventional construction.
ON THE WEB What's your idea of a green living or work space?
Tell us at sierraclub.org/sierra/shelter.