STRAW BALE CONSTRUCTION
By: Catherine Wanek
Could it be that the house of the future was invented a century
ago? In the 1890s, pioneers of the sand hills of Nebraska found
themselves building a new life on a treeless prairie, and from
necessity began building their homes from bales of straw. Now
modern day pioneers are choosing straw bale construction for
its many advantages -for people and the planet.
Straw bales offer excellent insulation. At R 2.7 per inch,
an eighteen-inch wide bale equals R-48. One California study
indicated that such a "super-insulated" straw bale
home could save as much as 75% of heating and cooling costs!
This translates to direct dollar savings for the homeowner, and
a corresponding reduction in the use of fossil fuels and CO2
emissions.
Construction costs can also be reduced when building with
straw bales. They are cheap to buy and easy to build with. Stacked
like huge bricks, straw bale wall systems can be erected quickly
without much building experience and few power tools. In a "barn-raising"
type party, it's common for all the straw bale walls in a modest
size structure to be erected in a single day.
Building with bales can also cut down on cutting down trees
by reducing lumber used in typical "stick frame" construction.
Straw is available wherever grain crops are grown, and is annually
renewable. In fact, it's considered an agricultural waste product,
and in many parts of the world is simply burned in the fields.
The millions of tons which go up in smoke every year cause a
great deal of air pollution. It makes sense to bale this nuisance,
and turn it into an energy-efficient resource.
Those concerned with indoor air quality also appreciate straw
bale buildings for their "breathability." A non-toxic
product itself, bales allow a gradual transfer of air through
the wall, bringing fresh air into your living environment, especially
when combined with a natural plaster. And you can forget about
neighborhood noise, too. Straw bales are so sound proof, one
Nebraska pioneer family was found playing cards in their kitchen,
oblivious to the roar of a tornado which had just blown through
the town.
Two types of bale wall systems are commonly built. In a "post
and beam" building, a wood, steel, or concrete framework
Is erected and bales are placed in the walls as insulation. Bale
systems can also bear the weight of the roof, as evidenced by
the historic Nebraska homes which were all load-bearing. In this
case, a top-plate is laid above the bale wall and secured to
the foundation by metal rods and/or strapping. The roof is then
attached to the top plate. In either system, the bale courses
are stacked in a "running bond," and pinned with rebar,
wood, or bamboo stakes. For added strength, chicken wire is commonly
wrapped inside and out, and sewn tight to the bales. Then an
earth plaster or cement stucco is applied as a finish. However,
bales will also hold plaster without wire mesh.
Under the watchful eye of instructor Peter Fust, an EPSEA
workshop student restrings bale to make 2 half bales.
click here for 2 more photos- total 89K
Common questions about straw bale homes include concerns about
fire, moisture, and insects. While individual stalks of straw
will burn, when condensed into bales, they actually resist combustion,
due to lack of oxygen. It's like trying to burn a phone book.
At a certified laboratory in New Mexico, a plastered straw bale
wall system easily passed a two-hour fire test, which is required
for commercial construction. Liquid moisture is a problem in
bale walls, as it is in any wall system. But with a proper foundation,
roof, and finish plaster, straw bale buildings can last indefinitely,
as nearly century-old homes in Nebraska prove. Anecdotal evidence
indicates no problem with bugs.
Building codes have been developed for both "post and
beam" and load-bearing straw bale construction. In New Mexico,
Pima County, AZ, and several counties in California, getting
a building permit for a straw bale house is almost routine. Farmers
Insurance Group will insure a bale home at preferred rates and
other companies are following suit. And straw bale houses are
gaining acceptance with Fannie Mae and HUD.
To contact Catherine Wanek:
Black Range Films
Star Rt. 2, Box 119 Kingston, NM 88042
505-895-5652.
E mail: blackrange@zianet.com.
Black Range Films has released its third video in a series
on "Building With Straw Bale". Their latest production
Straw Bale Code Testing will assist anyone, including code officials
in dealing with the permitting process.
The Black Range is now the publisher of "The Last Straw"
newsletter.
The
Black Range: Natural Building Resources
Check out this site for information on books, videos, workshops
and more
NEWS: Black Range - Natural Building Resources are now known
as Straw Bale Central (new name - same great folks)
More LINKS to Straw
Introduction
to The Last Straw: http://www.netchaos.com/tls/index.html
The Last Straw
http://www.strawhomes.com/
http://www.ecodesign.bc.ca/straw.htm
Burbophobia
Nice collection of general strawbale information, plus strawbale
happenings in the Rocky Mountain West. http://www.pcisys.net/~moxvox/straw.html
DOE
Straw Bale Housing Experiment http://www.eren.doe.gov/EE/strawhouse/house-of-straw.html
Strawbale
Mailing List http://crest.org/efficiency/strawbale-list-archive
To subscribe, send mail to strawbale-request@crest.org. No specific
Subject or body is required. You will receive instructions and
a description of the mailing list.
The Thermal Resistivity of Straw Bales for Construction
Joe McCabe's master's thesis http://solstice.crest.org/efficiency/straw_insulation/straw_insul.html
Greenbuilders Sustainable Building Sourcebook: , Strawbale
Construction http://www.greenbuilder.com/sourcebook/strawbale.html
Development Center for Appropriate Technology's website:
"Addressing Institutional Barriers to Straw Bale Construction"
http://www.dcat.net
Straw Composite Systems
http://www.cstone.net/edc/html/grsb.htm
Surfin Strawbale Links List
http://mha-net.org/html/sblinks.htm
New
Mexico Straw Bale Code
http://www.earthbuilding.com/nm-straw-bale-code.html
Straw Bale Association of Texas (SBAT):
P.O. Box 4211 Austin, TX 78763-4211
512-302-6766
http://www.greenbuilder.com/sbat/
Straw Bale House:
A Straw Bale student project. http://www.sccs.swarthmore.edu/~csunami1/straw.html
Out On Bale By Mail/Dawn
1039 E. Linden St.
Tucson, AZ 85719
520-624-167
http://www.greenbuilder.com/dawn
Tierra Madre - Straw Bale Housing Development
http://www.tmadre.org
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