OneVoice Newsletter August 2023

IN GOOD COMPANY
Vendor highlight:
The moisture problem
It has been generally known, for many years, that
most causes of unsatisfactory performance of
exterior house paints can be traced back to water in
one form or another. Moisture moves its way behind
the paint coatings, saturates wood, promotes the
growth of decay and incidentally, destroys the
adhesion of the paint to the surface. Water behind
paint coatings is the primary source of peeling and
unsatisfactory performance. However, all paint
coating failures are NOT attributable to moisture.
Other causes include: incompatible coats of paint,
painting under the wrong weather conditions,
condition of the substrate, or simply poor quality
paint. The easiest way to determine the cause of
peeling is to remove a piece of the failed coating. If
the paint coatings has failed to the point that the
substrate is completely bare, then moisture has
penetrated the backside of the coating. When the
sun evaporates the water, it pushes all the coatings
away from the substrate. If a paint coating fails and
previous coatings are still adhering beneath the
failed area, the source of the problem is usually not
moisture. Since the most recent coating of paint is the
portion of the surfaces which meets the eye, the
tendency of the casual observer is to blame the type
of paint or the application by the contractor for all
failures. Only after prolonged trials with various
brands and types of paint and numerous contractors
does it become obvious that some other factor is at
work. Water is the primary offender and shutting off
its sources is absolutely essential to ensuring the
longevity of a paint coating.
Sources of moisture
The first step toward a solution to
moisture failures is to identify its sources.
A smaller percentage of water may
penetrate paint coatings from the exterior
of the building by the following means: (1)
Siding which was warped, split, or shrunk
presents an excellent opportunity for
moisture to enter, (2) Exposed ends of
boards in contact with damp areas such
as soil, masonry surfaces, brush, shrubs,
etc…act with a capillary action drawing
moisture. An excellent example of this
failure involves the placing of wood
window sills on top of decorative concrete
window sills.
fsresidential.com/illinois
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