Skeptical about strawbale construction? Do visions of the three little piggies keep coming into your mind? Here are some answers just for you.

What about bugs? Wouldn't the bales become a home for lots of little critters?

Straw is comprised of the stems of plants. Straw contains no food value. Bugs see straw as being a lot more like the Sahara Desert than a leftover pizza. Termites, the bane of wood homes, don't have the right digestive processes to consume straw and can accurately be described as disinterested. The existence of sound, longstanding strawbale houses has proven that this is true. Just to be sure, strawbale builders now often take an additional, preventative step by sprinkling borax into the bales as they are laid. Borax is benign to the bales and humans, but lethal, or at least distasteful to insects.

What about fire? Straw burns pretty easily.

Loose straw, just like wood shavings, burns easily. Baled straw tends to simply smoulders. The key factor is how easily a fire can obtain oxygen; tight baling of the straw severely limits a free flow of oxygen. Most importantly, strawbale houses are traditionally covered with stucco. Tests have shown time and again that stuccoed strawbale houses have a much greater resistance to fire than do conventional wood structures. In fact, strawbale structure fire tests have shown that stuccoed strawbale construction is able to withstand temperatures of 1800 degrees Farenheit for over one hour with no structural damage, which is sufficiently fire resistant for stuccoed strawbale to qualify as a commercial building material. The growing list of county building departments which have approved strawbale construction is indicative that strawbale construction is not only safe, but is in fact safer than conventional wood construction.

Is straw prone to rotting?

Both wood and straw can rot if wall moisture content rises above about 70% for extended periods of time. New information from Canada and the U.S. strongly suggests that all superinsulated homes (of which strawbale homes are only one type) must be designed to avoid moisture buildup or rotting can occur. Some data on the degradation of wood even suggest that our past and current understanding of the dynamics of moisture and vapor barriers is incomplete, and that many newer homes with standard insulation levels which employ moisture barriers are at risk due to inappropriate installation of the barriers. Strawbale enthusiasts are, if anything, more knowledgeable about both the dangers of moisture and are more familiar the technques of moisture control than most builders of conventional homes. The final word regarding moisture is that it is a design problem that is shared by both wood and straw, and that buildings utilizing strawbale walls are no more prone to moisture degradation than houses built of wood.

The use of straw bales for homes is not a panacea for all latitudes and climates. While strawbale construction has a good record in arid and semi arid climates, the use of the method in locales of high relative humidity is much more problematic, and projects undertaken in these areas should incoporate all known methods for keeping wall blaes dry, as well as an ongong program of wall moisture monitoring. Those considering strawbale construction should ask whether it is appropriate for their specific conditions. The strawbale community of builders and enthusiasts is currently gathering data and developing methodology by which moisture levels can be ongoingly measured, and wall moisture levels can be regulated.

Do strawbale houses have problems being approved by building officials?

There is no shortage of engineering reports on the strength of strawbale walls, and approval by an engineer definitely eases the collective minds of building officials. Home floorplans which differ significantly from approved designs may require engineering reports, but such services are available at reasonable cost by a growing number of engineers who are familiar with and supportive of strawbale construction. As mentioned above, the growing list of counties in a number of states which approve of strawbale construction sets a precedent to which other local officials may refer if they are in doubt.

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James Lux, January 12, 1996