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Building
with Straw
by Chuck Hall
 In
spite of any childhood stories you may have heard about the Three
Little Pigs, homes made of straw are actually quite comfortable,
affordable and safe. Straw has the added advantage of being highly
sustainable. The types of straw used in straw bale construction are
by-products of grain harvesting. Straw that would otherwise be used
for animal bedding, landscaping, or just for kindling can also be
used to build homes. Straw is also an annual crop, unlike lumber,
which can take several decades to replenish.
Building
with straw was used in the plains of the United States way back in
the 1800s. Some of those structures are still standing as a
testimonial to the durability of this building technique.
Straw
bale buildings are made by stacking bales of straw inside a
framework. A stone or masonry footer is built first to keep the
straw dry by preventing contact with the ground. The framework
supports the roof and adds stability to the structure. It can be
made of wood or metal. Openings for windows and doors can easily be
cut using a chainsaw. Once the straw bale walls are in place, they
are finished with a coat of plaster. Concrete stucco is not
recommended, as it doesn’t allow the walls to breathe. Moisture
can potentially accumulate inside the straw, and it needs a way to
escape so that the straw does not mildew. It is therefore
recommended that you use an earth or lime-based plaster to improve
breatheability.
Amateurs
with little or no experience can build straw bale homes. The
finished result looks similar to adobe, and straw bale homes can be
built very inexpensively. These homes have been built for as little
as ten dollars per square foot. Additionally, straw has a very high
insulating factor, estimated at between R-35 and R-45!
 The
first question people generally ask about building with straw is,
“Isn’t it highly flammable?” While straw itself is flammable,
once it is coated inside and out with plaster it is very safe. The
plaster prevents the fire from getting into the walls from the
outside, and should a spark find a way inside the wall, the plaster
keeps the straw from getting enough oxygen to burn. When properly
constructed, a straw bale home is at least as safe as a traditional
stick-built home, and straw bale can be less expensive (if you
don’t use a contractor and do it yourself) and more energy
efficient.
The
main factor to consider with straw bale construction is damage due
to humidity. If moisture gets into the straw, it can cause mildew or
water damage. So if you are building yourself, take extra
precautions to limit moisture within the walls. A good beginner’s
guide to minimizing water damage in straw bale construction can be
found at: www.skillful-means.com/strawbale/papers/moisture.htm.
For
more general information on straw bale building, including a
directory of homes built with straw, visit the Green Builder’s
Straw Bale Construction site at: www.greenbuilder.com/sourcebook/strawbale.html.
Chuck
Hall is a Sustainability Consultant and author. His latest book, Green
Circles: A Sustainable Journey from the Cradle to the Grave, is
now available at Booklocker.com.
You may contact Chuck by email at: chuck@cultureartist.org or visit
the Culture Artist Web site at www.cultureartist.org.
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