Straw-Bale Housing

A Traditional Technique

The concept of building homes made from straw is not new. With rising material prices affecting the home building industry, builders have begun to rediscover this low-tech technique as an eco-sensitive way to cut costs and increase the affordability of finished units.

There are two basic methods for straw bale building: “Nebraska style,” which uses the straw bales for load bearing wall, or “In-fill” construction, which uses stacked bales as insulation in non-structural walls.

Straw-Bale Housing in Minnesota

In 1996, Minnesota's first straw-bale house permit was given in Northbranch, Minn. The wood beam house sits atop a concrete foundation. The bales are stacked within this frame and act as insulation. Bales are staggered like bricks, and steel bar-pins are used to bind the bales together. Sheetrock and stucco are used to finish the interior and exterior walls.

Community Ecodesign Network of Minneapolis received grant money from the Minnesota Housing Finance Agency (MHFA) to complete a straw-bale building demonstration project in 1998. The home had issues with moisture breaks and insect infestation and was eventually condemned.

To date, there have been about 12 straw-bale buildings built in Minnesota, but only two have required building permits—the rest have been agricultural buildings that do not need permits.

Existing Concerns

There are still many pieces of this construction technique to monitor in Minnesota: structural soundness, moisture control, straw’s thermal properties, embodied energy of straw-bale building, code regulations about straw-bale building, and value-added analysis of complementary materials.

Bales of hay are used as an
insulated wall system.

Bales are bound together
with steel cleats to prevent shifting.

Builders attach mesh directly to the
bales to provide a base for stucco finish.

 

 



Innovative
Construction Techniques

Manufactured Housing
Stress Panel Housing
Straw-Bale Housing

Pros and Cons

The largest cost benefits of straw-bale building come when the owner does not have to pay for labor costs to put up the walls of the building. Some cost benefits are visible in material costs, but due to the need to moisture-protect the bales, the benefits are not as dramatic as you might expect.

Benefits from using straw bales include:

  • energy efficiency;
  • resource-efficient building technology;
  • use of local materials (in many situations);
  • community involvement and use of local labor;
  • cultural compatibility; and
  • design simplicity, adaptability and comfort.

Drawbacks

The drawbacks of this construction technique are unresolved. There are serious questions about structural stability and moisture control.

In spite of being a green-friendly, resourceful building technique that cuts the one-time, short-term costs of construction, the ongoing costs associated with maintaining straw-bale housing does little to address the long-term provision of safe, quality, affordable housing.

Innovators in Straw-Bale Housing

For additional information on this building technique, refer to the following organizations.

US Department of Energy
Care 2 Make a Difference
Earth House
 The Last Straw