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GBlist: a treatise on straw bale
I don't get to spend much time these days replying to this or any other
list, but I feel compelled to make a few comments in response to things
that I've read here recently. First, I'm always disturbed by claims that
a given building system or material is appropriate everywhere. This
position is continually projected on proponents of building systems such
as straw bale, rammed earth, cob, etc., while most of us who have been
exploring and working with them for years tend to be very careful in how
we talk about them and in our characterization of what we do and don't
know about them.
I concur to some degree with what John Bower said about the inevitable
failures in straw bale buildings. I have been saying for quite awhile
that I guarantee that there will be moisture failures in straw bale
buildings - because there are moisture failures in virtually every other
type of building and I see no reason to expect straw bale structures to
somehow be immune to this problem.
On the other hand, I have probably seen as many of the older straw bale
buildings as anyone. And I remain convinced that this is a viable
building system in many different climates. There are some excellent
examples of the system, such as the Burke house outside Alliance,
Nebraska, built in 1903, abandoned in 1956 and still in very sound
condition in the summer of 1994, when I visited it and photographed it.
It has very small overhangs (about 12") cement stucco on the exterior
with no paint, wood lath and plaster on the interior (and yes, it had an
indoor bathroom and a kitchen). The baled meadow hay that was exposed
after 38 years of the ravages of the seasons, where the stucco had
cracked, showed virtually no signs of decay. Likewise, the places where
vandals had broken open the plaster inside did not reveal anything scary
or gooey. This 900 sf house was plastered with only mud on the exterior
for the first five years or so, because the Burkes were planning to build
a "real" house when they could afford to. It only took them that long to
figure out that they were already living in a real house, after which
they plastered it and lived in it raising 5 kids over a 53 year period.
They moved out because they wanted a much larger "modern" ranch house,
which they built for themselves about a mile away on their huge ranch.
I also have visited the two bale structures at Fawn Lake Ranch near
Hyannis, Nebraska, one built in 1914 and still in use as the headquarters
of the ranch and another built a few years later with 50's second story
addition which now serves as cook's quarters, having formerly been the
bunk house. The main house has wood panelling in much of the interior as
well as wood floors. These are also baled meadow hay (grasses) and both
structures are in use and serving well.
I have been in the Scott house near Gordon, Nebraska, built in 1938 and
one of the finest examples of the Nebraska style houses to be found. It
has the straightest roof line, flattest uncracked stucco and plaster
walls, and like the others, only reveals the bale structure (this one is
straw and like all the ones mentioned above is load-bearing) through the
thickness of the walls. This is true also for the Martin/Monhart house
built in 1925 (in which I've had the pleasure of sleeping on two
occasions) and the Pilgrim Holiness Church (1928) both in Arthur,
Nebraska. I know of about another half dozen in Nebraska, which date
from the mid-twenties into the late thirties, that I haven't visited but
Matts Myhrman and Judy Knox have. I've seen photos of those other
buildings and we've talked about them and all appear are reported to be
sound buildings.
I've visited several others in Wyoming (4) dating from the late forties
and early fifties, and South Dakota (2) where there is one built in 1921
using mortared bales (like bricks) and currently used for storage.
Though one could argue that these are all in somewhat drier climates,
colder certainly than the southwest, but with less rainfall and humidity
than the northwest, northeast and the south, there are examples in each
of those climates that, though some not as old, offer encouraging
evidence of viability.
The Burritt Museum, in Huntsville, Alabama, built in 1938 is another
impressive older bale structure in a non-arid climate (fairly severe
mixed climate - with an average annual rainfall over 50 inches and an
average relative humidity over 50%. It is a concrete post and beam
structure with bale in-fill and bales used as sound insulation between
floors (yeah, it's two stories with a basement) and in the attic for
thermal insulation. It often snows in Huntsville in the winter and gets
hotter then hell in the summer. The building is doing quite well by all
accounts. The Burritt is owned by the City of Huntsville and is open to
the public, so go check it out if you're down there (I've not visited
this one yet, though I know four people who have and whose opinions and
powers of observation I trust and I've seen their photos too).
I also had the pleasure of visiting a 1975 baled hay structure in Old
Saybrook, Connecticut during the NESEA Building Energy Conference
recently. This little cottage sits a short distance from a peat bog,
about five miles from the mouth of the Connecticut River and the coast.
It has no foundation - the bales, which Ben Gleason who built it
described as "hay that had gone by" were stacked on slightly mounded dirt
covered with a layer of plastic and then stuccoed inside and out using a
stucco mix consisting of "cement and some sandy soil from across the
road". I just happened to have my Protimeter Balemaster moisture probe
with me and we just happened to have a drill and permission to punch some
holes in the stucco, inside and out, and check for moisture in the bales.
What we found was amazing. This is an occupied house, at the end of
winter, in a far from benign climate, with virtually unsealed interior
walls (lots of gaps around door and window frames, at the floor and
ceiling, etc.) and we could not find any serious moisture accumulations
in the walls. The worst place we found was on the north side of the
building, down within a few inches of the ground, just inside the
exterior stucco and the reading was 20%! Most places we couldn't get
readings above 11%, the minimum the meter reads, and there were a few
places, like under a window, where we found 14% or 15% moisture. There
was NO evidence of decay that was visable or detectable by odor or
anything else.
And for contrast, a couple of weeks later, Tom Hahn (the Phoenix-based
architect who was the lead designer for the APS Environmental Showcase
home in Phoenix - and no, there's no straw bale in it), who edits The
Last Straw journal, and I tracked down a bale house in central Phoenix
built by a Taliesin West architect in the late forties or early fifties.
Here again, no signs of decay. In fact, we had a hard time convincing
the woman who is renting the place that, yes, in fact those thick walls
contain bales of either hay or straw. And for good measure, there's a
post and beam straw bale house in France which was recently restored,
built in 1921 and the straw is fine, and a baled straw church in northern
Alberta, Canada that was built in the fifties and at last report was also
doing well. I could describe some other buildings, such as the house
without a foundation or exterior wall finish after nearly 14 years
outside Tonasket, Washington, in which the bales are also not showing
decay - because they get wet but they can very easily dry out. Etc., Etc.
What does that tell us? Well, we know that it is possible for these
structures to last as long as wood frame structures in these same
locations. We know that none of these older houses used any exotic
barriers - perhaps the fact that they were not well sealed and had no
synthetic stuccos, foams, or other higher tech materials in them actually
helped them survive. Some if not all were originally heated with wood,
but many have "modern" gas, oil, or electric heating systems now.
As John Bower also pointed out, we don't know about the ones that didn't
survive, except for some photos and various anecdotal accounts of
structures that no longer exist. But we have a good collection of
structures that survive and we are working toward doing some careful
testing and evaluation of these older structures as well as comprehensive
testing of both bale wall systems and whole house testing. If no one was
willing to build anything but buildings that had long proven track
records, we would still be living in caves and the like.
I don't advocate building structures that will likely fail, or cause
problems for their owners or occupants. On the other hand, as someone
else mentioned, we simply cannot continue to build the resource
intensive, high impact, high cost structures that are the "norm" today in
what I recently heard referred to as the "over-developed" world. It is
really imperitive to find ways to use the materials we have in abundance
(and straw and earthen materials are certainly in this category). In
fact earth and straw have about as long a history of use together as any
building materials I can think of. We have developed some very peculiar
and dangerous notions in the over-developed world about our buildings,
what we need, how little we should ever have to think about or do
anything to them, and how detached it is permissable to be in regard to
the real impacts of what we do. I love technology used well and despise
it's mindless application in the pursuit of ego gratification, greed, or
sheer laziness. I define appropriate technology as the lowest level of
technology needed to do what needs to be done well, as opposed to our
cultural bias to use the highest level of technology (and its
accompanying high level of unintended consequences and impacts) we
"think" we can afford. What can I say, I like mud and straw.
That said, I will readily admit to living in an under-insulated concrete
block house in Tucson. Arizona, built in 1952 and requiring a fair amount
of energy to heat and cool (it's what I could afford). But I haven't
gone out and scraped off another acre of desert to build a new one for
us. And when I need to reroof (sadly/gladly still a few years away),
I'll have the opportunity to extend the eaves and wrap this house in
bales and use an earthen plaster - and I'll do it without hesitation when
I can.
Talking and exploring moisture issues with George Tsongas (at Portland
State University in Oregon), Bob Platts in Ottawa, Canada, as well as
conversations that I've had with Terry Brennen, Marc Rosenbaum, and lots
and lots of others, have lead me to the place that I think it is possible
to design and build bale structures successfully anywhere that it is
possible to build wood structures. Whether that is appropriate,
cost-effective, energy- and resource-efficient, etc. depends on the full
range of variables that need to be considered for any building in any
climate or location. Nothing works well everywhere.
Enough for now.
David Eisenberg
Director
Development Center for Appropriate Technology (DCAT)
PO Box 41144
Tucson, Arizona 85717
strawnet@aol.com
Note new fax number
(520) 624-6628 phone
(520) 798-3701 fax
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