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How Important Is Kiln-drying?
Kiln-drying provides many
important benefits. First, it produces logs that are more uniform and
dimensionally stable. Drying in a controlled environment minimizes
checking. Also, any logs that exhibit severe stress changes prior to
milling can be culled. The result will be a more uniform appearance for
wall logs and tighter wood joints.
Second, timbers are sanitized
when they are heated to 180 degrees F. in a kiln. Such heat kills mold,
wood decay fungi, and any insects, their eggs, or larvae.
Third, pitch in the wood is
crystallized by the heat of the kiln. This prevents the sticky substance
from seeping through the logs.
Fourth, more than 10,000 pounds
of water can be removed from a typical log house during the kiln-drying
process. This significantly reduces weight for both shipping and worksite
handling of the logs.
The final benefit to proper
kiln-drying is that interior and exterior finishes can be immediately
applied after construction. These finish applications tend to penetrate
deeper and therefore last longer on kin-dried wood.
While it is true that some of
these benefits may also be realized by proper air drying, there are some
benefits that simply don't result from anything except kiln-drying.
Kiln-drying can reduce wood moisture below what is possible with
air-drying. This results in better end-use performance in heated buildings
and in low-humidity locations. Additional benefits besides those
above include more stabile wood, increased strength and stiffness, and
tighter holding of screws. Strongwood logs are never sprayed or treated
with any kind of chemicals.
I am amazed as I travel and look
at homes from many different manufacturers and review their marketing
materials. Many companies claim that they kiln-dry their logs. Some boast
that they do not kiln dry but that they air dry their logs and suggest
that it is better than kiln-drying. Because the logs of some companies are
not fully dried, some manufacturers have unnecessarily elaborate assembly
systems to account for shrinkage or settling. Some companies indicate that they
dry their logs down to 23% moisture. Others do better and dry down to the
critical 15% to 19% range. But, you have to read the fine print to find
that they may actually only dry to the first 1 inch of thickness!
The drying processes used by
many log manufacturers is not that easy to decipher. You can be
assured that Strongwood logs are dried to 15% to 19% ALL THE WAY THROUGH
THE LOG. This drying process takes 28 to 34 days at optimum temperature.
Remember, quality comes from paying attention to details and not from
finding shortcuts or creating explanations for what it is not done
properly. We want your home to last a lifetime. |
