The first time I heard of straw bale construction was via Jen's Green Tour of Nord's Straw Bale Home. It seems like a rather unique idea, but in fact it's used all over the country and known for its low cost, easy availability and high insulation value.
At a recent home and garden show in Cleveland, a straw-bale structure was showcased as a sustainable and natural building method that is strong, and easy on the earth. Bales form the core of the exterior walls, then shaved to make the sides flat, and eventually coated with plaster, inside and out.
Here are a few benefits of straw bale construction:
- The R-value of straw bales is at least R-26 and possibly as high as R-50.
- Straw is a renewable resource that requires little energy to harvest.
- It can grow in a variety of climates all over the U.S. thus can be locally grown.
- Walls of straw-bale homes are thick, creating deep window and door recesses that are architecturally pleasing.
- It's nontoxic (including the plaster which can be made from soil from the construction site).
- It is labor-intensive - but what would be better for stimulating the economy than a green building process that's easy on the environment and creates more jobs.
Straw bale buildings are made in a few different ways depending on the builder, but the basics are the same:
- Bales are stacked in rows on a raised footing or foundation (typically of concrete) with a moisture barrier.
- Bales are tied together with bamboo, rebar, wood or wire mesh.
- Stucco or plaster is applied to both sides of the bales.
- Framing and load-bearing beams typically surround the bales to support the roof and other structure.
All of these beautiful photos are from a straw bale construction workshop in the Pacific North West.