Straw Bale Construction Advantages and Challenges

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Straw Bale Construction

As with any building style, straw bale construction presents its own unique set of advantages and challenges. Here is a quick overview of these issues.

Advantages

Straw bale walls are very well insulated. Not only is the ‘R-factor’ (a standardized measurement of resistance to heat and cold moving through a wall or ceiling) extremely good, but the thickness of the bales also insures much less leakage of heat or cold.
- A conventional 2x6 wall will have wooden or metal studs every 16 inches apart. Wood and metal are very poor insulators. Wherever the studs hit the outside wall there is a thermal break allowing the outside cold (or heat) to conduct directly into the home. Because of their thickness and therefore their high insulative value, straw bale walls conduct almost no heat and coldness.
Straw walls are gorgeous. Rather than expounding on this advantage, here are some examples of what I mean. Please note those deep window wells, the bookcases cut into the walls, the little ‘nichos’ carved into bales, the slight unevenness of the walls rather than a rigid straightness, and in particular the ability to easily curve and shape all straw bales. Enjoy!
Within the lower 48 states of the US, straw bales are almost always locally available. For example, here in the New Mexico/Arizona area, construction lumber is trucked in from as far away as Oregon or Georgia—a distance of maybe 2,000 miles—and steel is shipped from as far away as China—an incredible 13,000 miles! In contrast, I can purchase bales from farmers in Northern New Mexico, Colorado, or Western Texas. Needless to say, the amount of fuel necessary to bring me my building materials is exponentially lessened when using locally-available materials.
Straw bales are the byproduct of an agricultural commodity (wheat, oats, rye, barley, and rice). They are produced annually at no additional cost to the consumer in comparison to the decades it can take lumber to grow or the laborious mining and refining required for steel. Only a tiny fraction of our earth’s resources are used to produce straw bales.

Straw Bale Walls are very well insulated. The thickness of the bales insures much less leakage of heat or cold.

Challenges

Building with straw bales is not yet a fully-accepted method of construction in many parts of the country: plenty of building officials, inspectors, structural engineers and local authorities have been known to laugh in your face if you bring up the idea of building (or retrofitting) your home with straw. The oh-so-old joke of the three little piggies will invariably come up, along with some understandable concerns regarding insects, mold, and longevity. It may require more time to acquire a building permit for a straw structure than it would a conventional one.
Because of the thickness of the bales, one does lose square footage inside a home. The wall of a conventionally-built house is around 6 inches thick; a wall built with straw bales is three times as thick. To allow for the same amount of usable space inside a straw bale home, one must make the overall footprint of the structure several feet bigger to accommodate those wide bales.
The standard method of coating a straw bale structure is to apply stucco (a mixture of sand, cement, and lime) to both sides. This creates a sturdy ‘skin’ over the bales that can last for decades, and on the inside, one can smooth the stucco into an attractive surface. However, there are no studs at regular intervals to hang heavier pictures or mirrors or cabinets on—and so, alternate ‘hanging’ methods must be utilized which may at first be a bit confusing to those unfamiliar with them.