Brian Fuentes, AIA, www.fuentesdesign.com
Alex Platt, AIA, Solar Village, www.solarvillagelife.com
Jeff Ruppert, PE, Odisea LLC, www.odiseanet.com
Jeff DeMeyer, DeMeyer Construction Services, 303-931-6305
Ryan Chivers, Artesano, www.artesano-home.com
Associations & Resources
- Colorado Straw Bale Association (www.coloradostrawbale.org): Resource for local natural building with contact information for architects, builders, engineers, and plasterers.
- Builders Without Borders (www.builderswithoutborders.org): International consortium of builders constructing natural structures worldwide.
- Sustainable Sources Building (www.greenbuilder.com/general/buildingsources.html): Find out about events, news, and regional natural builders.
The Bale Facts
- Straw-bale structures are three times more energy-efficient than conventionally built homes.
- Dry straw will not degrade.
- The lifetime of a straw-bale-built structure can be anywhere from a few weeks to many thousands of years, depending on how well the structure is built and maintained.
- Straw, unlike hay, is pest resistant because it contains few nutrients.
- Straw-bale walls are extremely fire resistant—plastered walls will retard fire for up to two hours.
*Source: California Straw Bale Association
Deconstructing Straw Bale
- Frame: A two-sided wood frame holds bales in place.
- Straw bales: Bales are stacked like bricks, so the straw keys into itself, reinforcing the wall's stability. Each bale is approximately 14 by 18 by 36 inches, and weighs around 40 pounds.
- Slip layer (interior/exterior): After bales are in place, grippy clay slip is sprayed over the straw to provide texture for the next plaster layer.
- Straw clay layer (interior/exterior): A one-inch layer of combined earthen clay and straw pieces is hand applied, so that the five-inch fibers of straw work like rebar to glue bales together.
- Finish layer (interior): Made of lime, gypsum, or earth, the final 1/8- to 1/4-inch layer is a finer coat of plaster that can be mixed with pigment to color interior walls. Earth-based plasters help modulate humidity within the house, though gypsum is sometimes preferred because it is easier to nail or screw into.
- Exterior layers: First two layers are the same as above.
- Lime plaster layer (exterior): The exterior is sprayed with a thin coat of lime plaster, which offers more moisture resistance than gypsum. Pigment can be added to this layer as well or whitewashed onto walls using a water and lime mixture.
*Source: Brian Fuentes