Strawbale construction is the use of compressed blocks (bales) of straw, either as fill for a wall cavity (nonloadbearing) or as a structural component of a wall (loadbearing.) In each case, the interior and exterior sides of the bale wall are covered (by stucco, plaster, clay, or another treatment .) This sandwich of straw and plaster can offer structural properties superior to the sum of its parts. Both categories of strawbale design divert agricultural waste from the landfill for use as a building material with many exceptional qualities.

Advantages of strawbale construction:

• Excellent thermal and acoustic insulation – enhances comfort throughout the year
• Reduced construction waste: the main building material is a ‘waste’ and excess straw can be used on-site in compost or as soil-protecting ground cover
• Potential for major reduction in wood and cement use, particularly in load-bearing strawbale designs
• Requires no toxic treatments; can be good for chemically-sensitive individuals
• Can be highly resistant to vermin (including termites) in use, but biodegradable or reusable at the end of its useful life
• Can be economical. Strawbales are inexpensive, occasionally free, and owner/builders, unskilled volunteers, friends, and family can contribute significantly to labor.
• Aesthetic flexibility – from conventional linearity to organic undulation
• Usable in new construction, additions, and remodels

Considerations in strawbale construction:

• Straw bales may be plastered inside and out to provide thermal mass and, like standard construction, the walls must be protected from moisture
• Strawbale can be more resistant to termites and vermin than stick construction, but (as with any type of construction), elimination of cracks and holes is key.

Disadvantages of strawbale construction:

• If labor is done primarily by building professionals, the square-foot cost of strawbale construction can cost just as much as standard building methods
• Special measures must be taken to provide nailing surfaces, since straw bales do not hold nails as well as wood

Standard wood-frame residential construction practices require specialized skills and tools, as well as large quantities of wood, concrete, gypsum board (drywall), and fiberglass. While the environmental impacts of these materials are described throughout this guide, it's worth noting that construction in the United States consumes about 10% of the global industrial lumber harvest in a nation is home to about 5% of the world's population. Similarly, concrete, drywall, fiberglass insulation, and other building materials each have significant environmental impacts during extraction, processing, and disposal. Some standard building materials are also potential problems during application and use, such as toxic adhesives, binders and sealants. Strawbales are one of a range of ‘alternative’ building materials that help reduce or eliminate many environmental problems because they use plentiful, non-toxic, reusable, and biodegradable elements to build durable, comfortable, healthy places to live and work.

Strawbale construction was invented more than a century ago on the Nebraska plains, where waste straw was plentiful and wood was in short supply. Loadbearing strawbale construction, where the roof is directly supported by the bales, is termed “Nebraska-style,” while nonloadbearing strawbale construction involves post-and-beam support for the roof and the use of bales as a fill that insulates and defines the shape of the wall cavity. Greater familiarity and adaptability have made post-and-beam strawbale construction far more common than Nebraska-style. California Health and Safety Code Section 18444.40 - 18444.41 limits loadbearing strawbale structures to a single story in the absence of supporting engineering calculations.

Strawbale construction has been growing in popularity since the 1970s, and there are now thousands of strawbale homes in the U.S. Locally, two strawbale homes were completed in Santa Cruz County between 1999 and 2001, one in Capitola and one in the Live Oak area. By contrast, stick-frame construction has been standard practice in the United States since the end of World War II, but it remains uncommon in parts of the world with fewer timber resources.

Earthen Floors (1996) by Bill and Athena Steen
This widely read pamphlet is a great resource, but was under revision and out of print at the time of writing. The authors can be contacted for updates at www.caneloproject.com

The Santa Cruz Public Library System has many excellent resources on strawbale, including:

Also (not available from local public libraries at the time of writing):