The Straw Bale Home

by Julia Navaro / Arthur Morgan Institute for Community Solutions / August 28, 2014

            Straw bale home construction is a highly energy efficient construction method that has been around since the 1890s. It was not originally designed to be energy-efficient per se. Settlers in the Nebraska prairie had little access to timber for building homes and were not close to a railroad that could transport building materials to them. Straw, however, was plentiful; and with the development of the baling machine, settlers found they could use bales like bricks to build homes, churches, school houses, and grocery stores. They stacked the bales on top of each other and covered the structure with a sloped roof, a building style now called “load bearing” or “Nebraskan. ”The buildings provided a cool environment for the summers, and insulated the home in the winter. They also protected inhabitants from the harsh and loud winds on the prairie. Straw bale design dissipated in Nebraska around 1940 with World War II and the introduction of cement. However, the building style was rediscovered in the 1970s as environmentalists sought ways to build more energy-efficient and natural homes (Amazon Nails).

Today, the straw bale home has gained popularity worldwide and has been embraced as an energy-efficient building alternative to conventional homes. It is estimated that 1,000 new straw bale homes are built each year (Amazon Nails). Straw bale is an appealing building material for various reasons. It is a renewable resource with low embodied energy and straw is also a waste product from wheat, oats, or rice production that is frequently discarded due to excess production (Owens). It can be purchased cheaply—the overall cost of the wall unit could be 10–15% what it would be in a conventional home. Straw bale provides excellent insulation—with an R-value of 30–35 or higher—requiring minimal need for an air conditioner or heater (Owens). Furthermore, straw bales are surprisingly fire resistant, free from any toxic building substances, and form thick, aesthetically pleasing walls (Amazon Nails). In contrast, fiberglass insulation has high embodied energy and can be toxic, expensive, and is not biodegradable (Owens).

The original load-bearing or Nebraskan structure was the most popular method practiced initially, but several other building methods have developed with time and building experience.  Common straw bale building methods used today include the load-bearing and lightweight frame (post and beam), infill, and the hybrid method of these two. These new methods differ from load-bearing in that a frame and roof can be built before stacking the bale walls, which ensures that the bales stay dry throughout the building process and also provides greater support for windows and doors. However, the frame methods require more time, expertise, timber, and cost to build (Amazon Nails). Building with straw requires a foundation to keep the straw well off the ground and away from water. 

Posts and beams up

Adding the straw bales

 Along with the inherent insulation that comes with straw bales, such buildings can be made more energy efficient if designed in relationship to the local environment and climate. To achieve greatest heat gain in the winter, windows in the major living spaces such as the kitchen, living room, and bedrooms should be south-facing. Trees and shrubs can be planted to shelter the building from prevailing wind. In the summer, the home can be kept cool by adequate overhangs and by placing windows and vents in the shadier sides of the house (Keefe). 

Straw bales in

            Construction cost comparison between a straw bale or a conventional home are roughly equal. However, building costs could be substantially less if owners invest sweat equity in the construction process and volunteers help. Besides the basic wall structure of straw bales, the other construction and materials are nearly identical to conventional homes (Magwood).

The biggest disadvantage of straw bales is their susceptibility to water damage. Water damage can be avoided by incorporating appropriate building techniques. Damage from rainfall and splash back can be prevented by roof overhangs and gutters. Placing the bales on a wooden curb on the foundation prevents damage from floods and water spills. Plastic or tar paper can be fixed along the top of the straw walls to prevent water damage from roof leakage. Also, the walls should be coated with plaster and the ceiling and floor should be lined with a vapor barrier to prevent damage from condensation (Magwood). 

Applying the stucco exterior

Completing the stucco

Other potential challenges when building a straw bale home could include difficult access to straw bales and unfriendly building codes. If you live in a region where straw is neither produced nor baled, the financial and pollution cost of shipping them should be considered. Since the reappearance of straw bale construction is rather recent, it is not always incorporated into building codes and a building plan would need to be approved by local architects or engineers if not (Owens). 

Completed house, with solar panels

Literature Cited

Amazon Nails. "Information Guide to Straw Bale Building for Self-Builders and the Construction Industry. " 2001. (Feb. 18, 2008)
http://mauglee. kitox. com/files/strawbaleguide. pdf

Geiger, Owen. "Strawbale Questions and Answers. " Greenhomebuilding. com. (Feb. 18, 2008) )

http://www. greenhomebuilding. com/QandA/strawbaleQandA. htm

Keefe, Chris. "Straw Bale Design and Site Evaluation. " StrawBale. com. (Feb. 18, 2008)
http://www. strawbale. com/straw-bale-design-site-evaluation/

Magwood, Chris, Peter Mack, and Tina Therrien. "Expert Advice on Straw Bale Building. " The Mother Earth News Guide to Homes. Summer 2007 (Feb. 18, 2008)
http://www. motherearthnews. com/Green-Homes/2006-02-01/Expert-Advice-
on-Straw-Bale-Building. aspx

Owens, Ted. “The Pros and Cons of Building a Straw Bale Wall Construction in Green Building. ” Buildingwitha Awareness. com (Apr. 26, 2009)

http://www. buildingwithawareness. com/blog/2009/04/the-pros-and-cons-of-straw-bale-wall-construction-in-green-building/