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Frequently Asked Questions:
Q: I have heard a lot about
straw bale building techniques. Is this something new?
A: Absolutely not. This style of building has been around a long time.
There are straw houses built in Europe that
are over 400 years old. In the U.S.,
the settlers in Nebraska
built straw bale homes in the Sandhills region in the late 1800's. What you are
seeing now is a revival of an old idea, applying modern techniques. There are
now straw bale houses built or being built in every state in the U.S., and over
Q: Will straw bales and the HPBS system conform to the
building code in my area?
A: There is a specific straw bale code for New Mexico,
Most other states and/or counties allow experimental permits even if there is no
specific code. In some areas, your permit office will be concerned with the
safety of the structure, and will want to have more information before granting
a building permit. Independent testing data is available. Although we cannot
guarantee that you will able to obtain a permit, we have found nearly all
permit offices to be open to discussion, and eventually to understand the
process. In addition, every HPBS house plan comes with an engineer's stamp
specifically for your state, certifying a properly designed structure.
Q: What makes the HPBS system different from other
types of straw bale houses?
A: First of all, we only market "non load bearing" structures,
meaning that all of the weight of the structure is carried on the steel frame,
and none on the straw bales. This is critical in nearly all building codes.
Second, we have an engineered all steel frame system, making owner
participation in the building process much more accessible to the average
Third, we are the only company now incorporating all aspects of the building
process into their system, including design assistance, engineering, ongoing
construction advice, and financing advice.
Q: Can I be assured to get a mortgage?
A: One of the first steps is to discuss your specific financial situation with
us. If you qualify based on income and credit, you will likely be able to get a
construction loan and permanent financing. Straw bale construction is now
recognized by FNMA (FannieMae), the largest buyer of mortgages on the secondary
market, as well as other secondary market buyers, where all mortgage loans
eventually end up.
Q: Will I have to get my construction and mortgage
loans through HPBS?
A: Of course not. You are free to deal with any source of funds you choose. We
have found, after speaking to many national lenders, funding sources who are
friendly to steel/straw bale building. If your local source of funds knows and
understands the process, it may be easier to obtain the necessary funding in
your own backyard. If there is no one available to help you locally, we will
try to help you find a source as close as possible. Remember, qualifying for
the mortgage and locating a source of funds for your dream house is one of the
very first jobs you must accomplish before proceeding.
Q: Are straw bale houses really safe?
A: This is one of the first questions we had to answer at the inception of this
revival movement and the founding of HPBS. We held discussions with the
regulatory authorities (New Mexico Construction Industries Division), and were
told what they wanted to know.
We then carried out the specific testing that was recommended, namely, a
transverse load test, a fire resistance test, and an insulation test.
The fire and transverse load (wind resistance) tests were performed by SHB-AGRA,
Inc., an independent testing laboratory in Albuquerque. Here are the results:
The transverse load test was carried out to ASTM E-330 standards. A wall panel
of straw bales and standard stucco exterior was constructed. To be successful,
the wall panel must not show permanent displacement or failure in a wind of 20
psf (about 75 miles per hour). At this wind speed, the panel showed a 0.06
temporary displacement at the bottom and middle of the wall, and 0.13 at the
top, an extremely successful outcome. The wind severity was increased to 50
psf, which is maximum hurricane velocity, and the wall section was still
successful with no permanent deformation.
The fire resistance test was performed to ASTM Standard E-119. A similar wall
section was constructed and submitted to a blast furnace with measurement
thermocouples inside and outside the wall. To pass this test, the exterior wall
surface must not rise more than 250 degrees above the beginning temperature.
The internal temp was taken to 1000 degrees in five minutes, then 1550 degrees
in 30 minutes, then 1750 degrees in one hour. The highest temperature recorded
on the external side was 63 degrees when the internal side was at 1920 degrees.
There was no penetration of flame at any time, and at the conclusion of the
test, the wall was subjected to a blast from a 2" fire hose, with no
indication of distress or failure. This test was concluded after two hours with
no sign of failure. Needless to say, the testing laboratory personnel were very
surprised and impressed.
The final test, insulation, was carried out by the Sandia National Laboratory
It showed that straw bales tested were of "standard compaction" and
had an insulation "R" value of 2.67 per inch. Therefore, an 18"
thick bale, our standard building size, would have an R-48. When you include
the exterior stucco and interior plaster, the R value would rise into the low
50's, more than adequate for any climate.
If you move forward with HPBS, and you or your local building inspection officials
or permitting agency need more information about these engineering test
results, and the accompanying New Mexico CID conclusions, we would be pleased
to provide them.
Q: If the insulation is that much better, will I see
lower utility bills?
A:Without doubt. We have received reports from straw bale home owners that
their utility bills are much lower than the same size home built
"conventionally" with R-19 for the walls and up to R-40 insulation in
the roof. In some cases, they have documented bills showing a reduction of 80%
to a neighboring home of the same size, especially in harsher climates, paying
an average of $40. per month, to the neighbor's average $200. per month heating
Q: What is "green building" and do straw bale
A: We have seen many definitions of green building. The simplest explanation is
that "green" structures do not "contribute to the overall
decline in sustainability or the consumption of resources". Therefore,
seeing that straw and steel houses utilize recycled or low impact materials, we
can certainly be considered in the "green building" category. Until
recently, most straw, a waste byproduct of crops such as wheat, oats, barley,
etc., has been burned in the field, contributing to global pollution problems.
By using the resources of crop waste byproducts and recycled automobiles, we
are helping to solve several problems at once.
Q: Is there anything else I should be aware of in
planning my straw and steel house?
A: To make the process easier for everyone, keep a few things in mind when
planning your house.
First, be realistic. Only build what you need. That 5,000 square foot dream
home may look good on paper, but a well designed 3,000 square foot house may
suit you just as well. It's all a matter of compromise.
If you are starting out, and plan a family in the future, a HPBS house can be
added onto very easily, so start out small and plan to add on later when your
financial situation may be considerably better.
We strongly advocate radiant floor heating and pitched roofs in all HPBS
houses, as well as simple wall sections with as few jogs as possible on the
exterior walls. Straight walls are much less expensive to build than jogged or
When sitting the house on your lot, keep the solar orientation in mind. Take
advantage of the passive solar gain whenever possible. A passive solar
orientation could be a significant part of your heating needs in many climates.
Please keep all of these design elements in mind when working out your initial
floor plan. It will pay off many times over when you or your contractor carry
out the construction of your new home.
Stay tuned for more information and updated contacts.