Message text written by "BP - His DNA is this long."
>he process of wind, rain and sun will wear away paint and other
coatings. The process of moisture getting behind a film forming material
and causing it to lift off is a different action. (Examples: on my
window sills I get paint peeling every so often due to the water that
can get behind the paint film through small cracks in the paint film due
to expansion and contraction of the wood. My siding is asbestos
shingles, there I have no problems with water getting behind the paint.
As a result no paint peel but the paint layer does wear away over time.
It is time for me to repaint.)<

I have seen some interesting articles in the coatings journals over the
years 
with regard to why paint peels on some wood surfaces. Ever see a house
where
one trim board refuses to hold a coat of paint, while the immediately
adjacent ones
have no problem?

Studies have demonstrated that sunlight exposure, even for brief periods,
has a profound
effect on the surface structure of wood fibers. If you stack your lumber on
the job site, the
piece on the top of the stack will undergo UV-degradation if left exposed
for just a few weeks.

Solution: Sand the wood to a depth below the level of uv-degradation (more
aggressive sanding
required than one might expect), or flip it over and paint the other side.

Mike E.