Getting
Superior Results When Painting Masonry
If
you're eager to change the look of your stucco, brick or concrete
block home, painting is a popular and relatively easy way to
give your house a makeover. But to ensure an attractive and
long-lasting painted appearance, you should follow some important
guidelines, according to the experts at the Paint Quality Institute.
Adequate
surface preparation is the key to success with any paint job,
but it is especially important when dealing with any masonry
surface. Start by using a wire brush, power brush or power
washer to remove all dirt, unbound sand, efflorescence (salty
deposits), chalk or loose surface particles, including peeling
paint. If the surface has mildew or mold, it can be scrubbed
off with a solution of one part household chlorine bleach
to three parts water. Be sure to wear goggles, gloves and
a dust mask when doing these procedures.
Once
all dirt, mildew and efflorescence have been removed, the
surface should be thoroughly rinsed with clean water to eliminate
any residual particles, dust or chemical solutions. Now you
are ready to paint!
If
the masonry surface has not been painted before, it may be
extremely porous. Application of a latex masonry primer or
sealer will make the masonry less absorbent, and provide a
smoother, more uniform surface for the paint. A primer or
sealer is especially helpful if the surface has powdery "chalk"
that cannot all be removed, or has a tendency to produce efflorescence.
Rough surfaces, as with cinder block, can be smoothed out
by application of a latex block filler, before applying the
finish coat.
Before applying any type of latex coating, you may want to
dampen the masonry. Pre-dampening is helpful if conditions
are such that the latex coating would otherwise dry very quickly,
resulting in poor film formation. Conditions that can make
the coating dry too quickly are: a porous surface that draws
water from the paint, painting on a surface that is hot from
sunshine, or applying the paint in direct bright sunshine,
or in very dry or warm breezy weather.
Fresh
stucco has its own set of painting rules. Fresh stucco should
be allowed to "cure" for four weeks, to allow for shrinkage
and reduction in moisture content and surface alkalinity.
To help prevent efflorescence from forming, hose down the
stucco once or twice a week during that period. Before painting
any stucco less than one year old, you should coat the surface
with an alkali-resistant primer recommended for masonry surfaces.
This forms a barrier against the surface alkalinity in the
stucco, which can degrade the topcoat and cause the color
to fade.
Once
the careful preparation of the surface is complete, you may
now begin to paint. The best choice for masonry surfaces --
especially relatively fresh masonry -- is a top quality 100
percent acrylic latex exterior paint. These paints are formulated
for use on masonry as well as other building materials, and
typically provide an excellent appearance for up to 10 years
or more.
If
the masonry has hairline cracks, however, you might consider
using an elastomeric wall coating instead of a conventional
paint. Thick and elastic in nature, this relatively new type
of coating has the ability to stretch and "bridge" small cracks.
Should you decide to use an elastomeric wall coating, you
may want to have a professional painter do the job.
For
more information about painting masonry, or any other painting
topic, visit the Paint Quality Institute Web site at www.paintquality.com.
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