Photo credit: Nancy Wicks/Round Mountain Institute.
Among the green building solutions available to homeowners today is the straw-bale house. What is a straw-bale house? Its structure is made up of bales of straw (usually wheat, oats, rye, barley, or rice), covered with a siding material, such as stucco. Many buyers shy away from this economical solution based on misconceptions and misunderstandings. Find out what straw-bale construction is really all about. Here are the commonest myths about straw-bale construction, followed by the facts.
Myth: Straw-bale homes catch fire more easily than stick-built homes.
Fact: Although straw in a field is highly combustible, the straw bales used in construction are tightly compacted to contain very little air. As a result, they will not easily combust. Bales covered with plaster or stucco are fire-resistant and provide even greater insulation. Other siding materials such as wood or aluminum are less desirable, since any gaps allow more air along the straw-bale surface and increase the risk of fire.
Myth: Rodents and wood-eating insects are a risk.
Fact: Hay provides food value to animals and insects, but straw does not. Straw is used to build houses because it does not attract rodents, termites or other insects. Actually, a conventional, stick-built house is more likely to suffer a termite infestation than a straw-bale house.
As with any home, proper maintenance and repair ensures that your straw-bale home will provide many years of comfort and safety.
Myth: Straw-bale homes trap humidity.
Fact: Because the straw bales are porous, they "breathe," allowing humidity to circulate out of the walls. The result is that moisture content hovers at less than 20%, similar to most other types of homes in the same area. In humid environments, builders recommend using lime-based plasters to cover the straw bales.
Myth: Straw-bale houses rot in areas of high rainfall.
Fact: Rainfall is not a problem in properly constructed homes. Waterproof barriers and properly engineered ground and roof drainage systems will mitigate any risk of rot.
Myth: Straw is organic so it will decompose.
Fact: Yes, straw is an organic material but in order for it to decompose both air and water are required. If your home is properly built to reduce air pockets and humidity, the straw will not decompose. Rice straw is a particularly decay-resistant building material.
Myth: Straw stinks.
Fact: If straw is properly plastered and protected from precipitation with a large roof overhang, it will not stink. In addition, since straw is a natural material it will not off-gas toxic volatile organic compounds (VOCs) or "cut" you like fiberglass insulation. However, straw will provide a greater insulation value than fiberglass and have zero VOC meaning it is greener for you and for the environment.
Myth: Bales are bulky and limit my design creativity.
Fact: Bales provide interesting architectural nooks and ledges. Spend some time perusing the many creative designs available and you will see that your creative options are unlimited.
Myth: Stick-built homes are just as "green" as straw-bale homes.
Fact: Straw is a sustainable, inexpensive resource. According the California Energy Commission, over 200 million tons of straw is generated in the U.S. every year. Rather than burning straw and producing tons of environmentally destructive carbon dioxide, you can convert it into a home that lasts for hundreds of years.
It takes less energy to heat and cool a straw home than a stick-built home. The R-value of a straw-bale wall is between R-32 and R-42, two to three times better than the walls of most conventional homes. The bales also provide a highly effective sound barrier.
Builders and homeowners interested in reducing their carbon footprint, using renewable and sustainable building materials, and reducing costs to heat and cool their structures will find straw-bale houses to be a worthy option for consideration.
Contact a licensed contractor to discuss your construction and home improvement needs.