David Flood
wrote:
I use Weatherseal on my log home my south side of the home the finish
breaks down and seems to flake off. Is the finish still penetrated in the
wood? Also what would be the correct action to take to combat the effects
of the sun on the south side? Which is what I think would be causing it.
Should I be coating it more often? Also if I could get the users guide and
maintaining log structures.
Thank You
David Flood
David,
The penetration issue for wood stains is a misunderstood
and an erroneously held concept by a lot of log homeowners. Penetrating
stains, ones that don't form a film, are usually low solids coatings that,
because of the minimal amount of resin solids in these products, deposits
small amounts of resin on the surface. Essentially these types of stains
color the wood but provide no significant protection. They don't peel because
there is not enough protective material on the surface to peel. Protection
and longevity comes from the type and amount of resins, pigments, fungicides
and water-repellents employed in the formula. There must be some film on
the surface of the wood in order to adequately separate the wood fibers
from the elements. The other family of stains that don't peel are non-drying
oil stains, usually paraffinic or mineral oil stains. These types of oils
don't form a continuous film. You can put motor oil on a piece of wood and
it won't peel either. But there is reason non-drying oils are not generally
used as the basic component in wood stains. For one thing these types of
stains make good dust magnets. They take a long time to really dry and is
why the surface often needs to be wiped free of excess oil. More importantly,
oils do not hold up well to the elements because their chemical structure
limit their ability to provide good UV and weather resistance. Often they
do incorporate pigments into these stains but there is a tendency for the
pigments to leach out of the oil. The bond of WeatherSeal to the wood fibers
is important. How well the coating adheres depends on the surface preparation
of the wood to be coated. Also, the amount and type of pigments used in
the stain and the degree of weather exposure will play a significant role
in how rapidly the coating breaks down. If you choose a lighter, more transparent
color, its ability to partially block the effects of sunlight is less than
a more pigmented system. Consequently a lighter stain allows more UV to
penetrate the coated wood fibers. The wood fibers the stain is adhering
(as well as the stain) will eventually erode and effect the mechanical bond
of the stain to the wood fiber. The outcome is a release of the stain coating
from the wood fibers. Moisture also plays a significant role in this erosion
process. Additionally, if the surface is not cleaned properly or the stain
is applied in cold temps, etc, the life of the stain is shortened because
the surface profile or the conditions of application did not allow WeatherSeal
to secure a good bond. If applied correctly to a wood surface that is properly
cleaned, WeatherSeal normally does not peel to any great degree. As it reaches
its service life, WeatherSeal will start to break down and erode off the
wood surface. At that point, you pressure-clean the logs and apply a new
coat(s) of WeatherSeal.
Michael McArthur
Continental Products Co.
