Expert Advice on Straw Bale Building

Enlarge Image Image Gallery Routt County, Colo. ALL PHOTOS COURTESY NEW SOCIETY PUBLISHERS; LAURA TAYLOR

Surprising answers to common questions about this popular alternative building method.

By Chris Magwood, Peter Mack and Tina Therrien

Houses made from straw bales are attractive, affordable, energy efficient, environmentally friendly and can be designed to match the owners personal needs, aesthetics and budget. These homes are made by stacking rectangular bales of straw and covering them with a plaster shell. Straw bale walls are at least twice as energy efficient as those from conventional stick-frame construction and will save you money on heating and cooling bills. Such savings are among many reasons why straw bale building is no longer a fringe idea, but one that has spread throughout North America and the rest of the world. Other attractions include its adaptability, hands-on building satisfaction and the cozy atmosphere created inside these homes.

With this recent surge in popularity, the collective knowledge built from the successes and mistakes in this grass-roots movement has helped the technique evolve we now know much more about what works and what doesnt. So before you decide if straw bales are right for your dream home, heres expert insight into common questions about fire resistance, moisture, pests, building costs, mortgages, insurance and resale value.

Fire Resistance

Straw bale walls are naturally fire resistant. While loose, dry straw is combustible, but when it is compacted into bales, theres not enough air for the straw to burn well. For a good analogy, compare the combustibility of a single sheet of newsprint to that of an entire telephone directory. A single sheet will burn quickly, but a phone book will just smolder. Combining plaster with the compactness of a bale wall enhances fire resistance. The plaster coating effectively seals the already fire-resistant bales inside a noncombustible casing. According to fire safety tests conducted by the National Research Council of Canada, bale walls withstood temperatures up to 1,850 degrees for two hours.

Moisture

Regardless of which materials you use to build your house, moisture is an enemy, and this topic is hotly debated among bale builders. When built correctly, straw bale homes dont pose any greater moisture risk than conven- tional buildings. According to the 2000 Strawbale Moisture Monitoring Report, submitted to the Canada Mortgage and Housing Corp., straw bale walls do not exhibit any unique propensity for moisture retention.