Design your own custom log cabin house using our design plans
If you love the beauty of a log home but want
the super energy efficiency of a structural insulated panel
home, then our home kit is definitely the right choice for
you. Our unique panelized home system can be finished anyway
you like, including the beautiful look of a log home.
Once your panelized home kit is built, you
can then attach log siding (supplied by customer) to the
exterior, giving the appearance of a log home with the benefit
of a fully insulated panel home. The result is a panelized
home that looks and feels like a real log home, with a higher
insulation factor than a log home.
Our panelized home kits
combine time and
money saving techniques that make it very easy and efficient
to build. The pre-engineered R-25 solid insulated wall panels
keep you warm in the winter and cool in the summer when
compared to traditional log homes. Log homes generally have
an insulation factor of only R8, extremely low by today’s
standards. Log homes are also susceptible to air leakage
by virtue of their design and the way in which they are
constructed. Logs tend to shrink over time as they dry and
gaps between them increase leaving holes allowing air from
the interior to escape and air from the exterior to penetrate
the structure.
Best of all, our home kits are delivered partially
prefabricated. This means that construction is fast and
simple, especially when compared to building a log home.
For more information on building a log home
using our system, please visit and fill out the contact
us page of our web site, or call us directly at 1-800-553-5907.
To demonstrate these issues further, we have
included a report from the US Department of Energy on the
energy efficiency of log homes (or lack thereof). The report
also discusses other issues with log homes.
Log Homes and Energy Efficiency
Log homes may be handmade on site or pre-cut
in a factory for delivery to the site. Pre-cut log home
kits have been produced since 1923. Some log home manufacturers
can also customize their designs. Wall thickness' range
from 6-16 inches (15.2-40.6 cm). However, even though such
thickness sounds impressive and the log industry enthusiastically
promotes the energy efficiency of log buildings there is
considerable dispute as to their energy efficiency. The
dispute originates from two points: The R-value of the wood
and how tightly the logs fit together.
The R-Value of Wood
An R-value (Btu/ft2/hour/oF) is the rating
of a material's resistance to heat flow. The R-value for
wood ranges between 1.41 per inch (2.54 cm) for most softwoods
to 0.71 for most hardwoods. Ignoring the benefits of the
thermal mass, a six inch (15.24 cm) thick log wall would
have a clearwall (a wall with no windows or doors) R-value
of just over 8. Compared to a conventional wood stud wall
[3½ inches (8.89 cm) insulation, sheathing, wallboard, a
total of about R-14] the log wall is apparently a far inferior
insulation system. Based only on this, log walls do not
satisfy most building code energy standards. However, to
what extent a log building interacts with it's surroundings
depends greatly on the climate. Because of the log's heat
storage capability it's large mass may cause the walls to
behave considerably better in some climates than in others.
Logs act like "thermal batteries" and can,
under the right circumstances, store heat during the day
and gradually release it at night. This generally increases
the apparent R-value of a log by 0.1 per inch of thickness
in mild, sunny climates that have a substantial temperature
swing from day to night. Such climates generally exist in
the earth's temperate zones between the 15th and 40th parallels.
Air Leakage
Log houses are susceptible to developing
air leaks. Air-dried logs are still about 15%-20% water
when the house is assembled. As the logs dry over the next
few years, the logs shrink. The contraction (and expansion
- see below) of the logs opens up gaps between the logs,
creating air leaks and causing drafts and high heating requirements.
To minimize problems like these, logs should be seasoned
(dried in a protected space) for at least six months before
construction begins. The best woods to use to avoid this
problem, in order of effectiveness, are cedar, spruce, pine,
fir, and larch. Since most manufacturers and experienced
builders know of these shrinkage and resulting air leakage
problems, many will kiln dry the logs prior to finish shaping
and installation. Some also recommend using plastic gaskets
and caulking compounds to seal gaps. These seals require
regular inspection and resealing when necessary.
Water Problems
Since trees absorb large amounts of water
as they grow, the tree cells are also able absorb water
very readily after the wood has dried. For this reason a
log building is very hydroscopic (logs absorb water quickly.)
This promotes wood rot and insect infestation. It is strongly
advised to protect the logs from contact with any water.
One concept is to only build with logs that have had a water
proofing-insecticide treatment and applying additional treatments
every few years for the life of the house. Generous roof
overhangs, properly sized gutters and down spouts, and drainage
plains around the house are critical to making the building
last.
Code Compliance
Several states, including Pennsylvania, Maine,
and South Carolina, have exempted log-walled homes from
normal energy compliance regulations. Others, such as Washington,
have approved "prescriptive packages" for various sizes
of logs. These may or may not make sense in terms of energy
efficiency.
Getting Approval
The American Society of Heating, Refrigerating,
and Air Conditioning Engineers (ASHRAE) 90.2 standard contains
a thermal mass provision that may make it easier to get
approval in those states that base their codes on this standard.
To find out the log building code standards for your state,
contact your city or county building code officials. Your
state energy office may be able to provide information on
energy codes recommended or enforced in your state. The
referrals below are additional sources of information.
As with any structure, properly designed passive solar methods
can lower energy use and help you gain approval for a log
building that would not otherwise comply with your state
energy codes. Factors to consider include:
- Size, type and placement of windows;
- Orientation of the building;
- Airtightness of the structure;
- Size and type of logs used;
- Amounts of attic and floor insulation;
- Heat storage mass inside the building;
- Local climate conditions.
Consulting a passive solar architect may
be worthwhile since the proper sizing of the sun exposed
windows is crucial to the efficient performance. Some designers
suggest incorporating thermal storage such as masonry floors
or walls, to absorb solar energy and increase the thermal
mass effect. Some log home manufacturers offer solar log
homes, or are able to custom-build them.
Article from the US Department of Energy
can be found at http://www.eere.energy.gov/consumerinfo/factsheets/ca8.html
Keeping all this in mind, you can still achieve
that log home look and feel you want while enjoying the
energy efficiency of a structural insulated panel home with
our panelized home kits.
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