Timeless Tips
PRESERVATION & CLEANING
What should I put on my log home to protect it?
In order to properly address this question, it's imperative
to understand the intimate connection between a building's
location & design and a coating's performance. The location
and design of a log building is a key contributing factor
to long-term maintenance costs. This very important detail
is too often overlooked. Different locations will frequently
require different building designs. If the building is not
properly designed for its location, then surface maintenance
inevitably becomes a more regular task no matter what brand
of exterior wood coating is used. And when a coating fails
to live up to expectations because of location and design
factors, it usually gets the full blame. The wood finish becomes
an easy target because its breakdown is so obviously visible
and is regarded as the cause of failure instead of a symptom
of deeper underlying causes. A quality log home finish, although
it will certainly perform better than the cheaper varieties,
will never achieve its full performance potential when design
considerations have been overlooked. A wood finish alone can
never remedy design deficiencies, no matter how good it is!
Nevertheless, the type of coating to use on a log home should
possess the following characteristics:
- Exceptional Water Resistance
- Shield the Wood Against the Sun's Harmful Rays
- Prevent Graying and Hold Color Longer
- Discourage the Growth of Mold & Mildew
- Protect Against the Abrasive Elements of Weather
- Allow for Some Degree of Moisture Vapor Transfer
- Have Minimal Impact on Air Quality
A Unique Challenge
Log homes pose a unique challenge, for any type of exterior
wood coating because the mass and surface of a log will vary
from log home to log home. Each individual log can contain
varying moisture contents, differing amounts of resin, a predominance
of bark, cambium, sapwood or heartwood surfaces, and different
densities of growth rings. In addition, log products are skip-peeled,
draw-knifed, finely milled or somewhere in between and also
come in various sizes, shapes and profiles. And let's not
forget all of the numerous types of species of wood. Unfortunately,
it's not possible to design a log home coating that will wear
in a similar manner over such a wide range of variables.
Finishing touches
Prior to coating with a wood finish, a new log home normally
requires a seasoning period to allow moisture within the logs
to be released to the outside environment. The moisture content
of a particular log building will vary from one manufacturer
to the other, so it is best to consult with your log manufacturer
for advice on when to first coat the exterior logs. Generally,
it is recommended to wait a minimum of 6 months after the
home has been built before applying the first coat. This allows
the log's surface to open up and dry which in turn makes a
better surface for a wood finish to absorb into and bond to.
To play it safe, apply only one coat of stain on your new
home. If too much stain is prematurely applied, moisture-related
coating problems such as mold, mildew, and peeling may occur.
This initial single coat should provide adequate protection
on the log walls for the first year. Normally another single
or double coat will be necessary the following year.
Before coating, spray the logs with the bleach solution mentioned
earlier and pressure wash clean at 500-750 psi. Additional
surface preparation may be necessary on logs that contain
mill-glaze, bark, cambium, or are altered by a draw-knife.
On such logs, scuffing the surface with a non-ferrous wire
brush or with medium to coarse grit sandpaper will help to
insure a better performance of the coating.
Once the home has seasoned, the performance of subsequent
coatings should improve considerably. The frequency of reapplications
will depend on climate, location, extent to which surfaces
are sheltered from weathering, nature of the wood, quality
of the finish, and application techniques. If the logs are
checking and cracking exposing untreated wood, or if the finish
shows signs of wear and is not providing an adequate water
barrier, it's time to recoat. Also, the Southern and Western
exposures absorb the full force of the elements more directly,
so expect to recoat those areas more often.
Your Ends Are Special
Special attention should be given to exposed log ends. End
grain absorbs twelve times more water than the rest of the
log surface. If left unprotected, end grain is particularly
susceptible to fungal attack. To prevent such an occurrence,
periodic inspection and treatment of the log ends with a quality
water-resistant finish is advised. In addition, waterproofing
the end grain will significantly reduce checking of the log
ends.
An Internal Dilemma
Many new log homeowners desire a transparent, cleanable surface
on the inside log walls that only a varnish type coating can
provide. Because varnishes are basically a clear paint that
forms a film, it is important that the logs are adequately
dry before applying such a coating. Otherwise, as previously
discussed, moisture-related coating problems could occur.
Since the amount of moisture in the logs will determine the
length of time required to wait, it is best to consult the
manufacturer of your logs for their recommendations regarding
a time frame for applying an interior varnish. If any doubt,
wait at least 6 months and through a heating season before
coating the inside logs with a varnish. Never apply a varnish
on the outside logs!!!
Check It Out
Another area of concern is the formation of cracks or checks
in the logs. Although there is a variety of factors that cause
checking, our concerns are checks caused by moisture.
There are two sources of moisture that contribute to log surface
checking:
- Internal
- Environmental
Internal moisture is the water inherent in the tree when it
is freshly cut. This water is located within the wood cells
and in their cell walls. The moisture within the wood cell
is known as free water and is the first to be eliminated in
the drying or seasoning of the wood. Free water is eliminated
when the logs have reached around 30 percent moisture content.
All moisture located in the cell walls is known as bound water
and does not begin to leave the wood until all the free water
from the wood cells is eliminated. As the water in the wood
drops below 30 percent moisture content, the release and elimination
of bound water begins. It is during this stage that log shrinkage
and checking occurs.
Ideally, in the "seasoning" stage, moisture in the
logs should decrease at a steady, even rate. The more rapid
the rate of moisture release, the greater the probability
of checking. Consequently, a slower release of moisture will
reduce checking and provide a more uniform shrinking and settling
of the logs. Since numerous variables contribute to the rate
and volume of moisture exchange from the logs to the environment,
control of this natural process by the homeowner is best achieved
by the maintenance procedures already discussed.
Environmental moisture is caused by moisture from the external
surrounding environment such as snow, rain, lawn sprinklers,
etc. As the wood surface becomes wet, it swells or expands,
and as it dries, it contracts or shrinks. When the wood is
subjected to a number of these wet and dry cycles, and in
winter climates freeze/thaw cycles, the stresses that result
cause cracks in the wood. All the precautions and methods
mentioned earlier in relation to controlling fungi apply here.
Once again, the whole object is to keep the logs dry. That
is the reason it is so important to apply a good quality,
water-resistant wood finish. Such a finish will provide the
necessary water-repellency needed to minimize moisture-related
cracks.
Finally, don't overlook upward facing checks. They can be
a nagging source of air and water infiltration. The wider
and deeper they are, the greater the potential for problems.
Sealing the checks with a caulking material will usually remedy
the situation, but it's a smart idea to saturate them first
with a wood preservative before caulking. This precaution
will greatly reduce any chance of rot. Before proceeding,
contact your log home manufacturer for advice on the type
of caulking to use and the best procedure to follow to properly
accomplish the job.
This sections content was provided by The Continental Products Company. |
