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How a finish is applied to cedar is as
important for durability and good performance
as is the finish-substrate combination chosen
for the job. Finishes can be brushed, rolled,
sprayed or applied by dipping. The application
technique, the quality and quantity of finish
applied, the surface condition of the substrate,
and the weather conditions at the time of
application can substantially influence
the life expectancy of the finish. The following
application guidelines should be followed
in concert with the manufacturer's directions
for the product.
Paints
Paints of all types such as vinyl-acrylic,
modified-acrylic, and oil-based top coats
are all suitable for cedar but test results
show that good-quality 100%-acrylic formulations
perform best. To achieve maximum paint life,
follow these steps:
1. On bare new or restored cedar, apply
one coat only of water-repellent preservative
(1% or less of wax by volume and content).
Allow it to dry for the period of time recommended
by the manufacturer. If the wood has been
dip treated, a longer drying time may be
needed. Do not paint before the solvent
from the water-repellent preservative has
evaporated because the paint may discolor
or dry slower with a rough surface.
2. Apply a good quality stain-blocking
primer as soon as possible after the water-repellent
has dried. The primer coat is very important
because it forms a base for all succeeding
paint coats and should be used whether the
top coat is oil-based or latex-based. Application
rates recommended by the manufacturer should
be followed.
3. Apply the top coat over the primer.
If two top coats are to be applied, allow
the first to cure for the period recommended
by the manufacturer before applying the
second. In cold or damp weather, allow extra
time between coats.
Water-Repellent Preservatives
Water-repellent preservatives should be
used only on newly manufactured bare cedar,
on restored bare cedar, or on cedar previously
treated with the same type of product. Application
of preservative by brush, pad, or roller
followed by thorough back-brushing is equally
effective. When cedar is treated after the
structure has been completed, liberal amounts
of the solution should be applied to all
lap and butt joints, edges and ends of boards.
Other areas vulnerable to moisture penetration,
such as below doors and window frames also
need to be treated.
When used as a natural finish, the service
life of a water-repellent is only one to
two years depending upon the wood and the
exposure. Treatments on textured surfaces
generally last longer than those on smooth
surfaces. Dip treatment prior to installation
or repeated brush treatment to the point
of refusal will enhance the finish durability.
The more finish absorbed by the wood, the
longer the service life. If a water-repellent
preservative is used as a pre-treatment
before painting, apply only a single coat,
and use caution to avoid excessive build-up.
Carefully formulated
semi-transparent stains have been developed
to retain the uniqueness of cedar siding.
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Opaque stains are high in pigment content
and, as in this country home, thoroughly
hide the color, grain and texture of
the board-and-batten cedar siding. |
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