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Exterior Paint
Problems
A fresh new
coat of paint can totally transform the exterior of your
house. The appearance and value of your house will improve
and the paint will also provide many added benefits to the
lasting quality of it. Quality paint can protect a home
against damage from environmental elements such as
moisture, ultra-violet rays and even structural pests.
However, lasting quality and protection involves more than
just a coat of paint. The right preparation, superior
materials and quality workmanship are also essential to a
thriving paint job.
In general, exterior painting is more complex than
interior painting due to the various environmental
elements to which a home's exterior is subjected. Peeling,
blistering, chalking, and rust, mildew, cracks and
chipping are some of the most common exterior paint
problems. Below are some descriptions of what causing
these paint problems and ways to prevent them from
happening.
Peeling: The most common cause of peeling paint is
from too many coats of old paint. Other factors that cause
peeling include moisture and a poorly prepared surface
that is chalky, dirty, greasy or slick. Proper preparation
before a paint job can prevent peeling from happening. If
it’s too late, and your exterior paint is already peeling
then you can remove it by sanding, scraping, power washing
or using a heat gun. The use of a torch is also a method
for removing peeling paint, but it is recommended that you
leave it for a painting professional due to the fire
hazards involved.
After you have removed all of the peeling paint, it is
vital for you to repair bare wood and voids by using a
high-quality exterior grade vinyl spackling compound. Then
you should sand these areas. Shrinking may occur so be
prepared to add more than one coat. Lastly, all patches
should be spot-primed with a high-quality oil-base
primer-sealer. These steps are crucial to preventing your
next coat of paint from peeling in the future.
Blistering: Blistering is usually related to a
moisture problem. The blister forms when water vapors
attempting to escape are trapped by the paint. To prevent
this form happening, you should always let new lumber
fully dry before painting. Additional causes of blistering
include excessive heat, painting in hot weather, overly
thinned paints and poorly prepared surfaces. You should
always have a vapor barrier below the siding to help
prevent moisture-related blistering. Also, interior
moisture control and insulation at exterior walls can
assist in preventing blistering.
Chalking: At some point or another we have all
noticed that powdery substance on the exterior siding of a
home. Most people don’t think twice as to what it is. Well
it’s actually the result of a chemical breakdown of the
ingredients in paint and is referred to as "chalking."
Environmental elements break down the pigments, binders
and solvent in the paint. Chalking is also commonly caused
by poor priming, overly thinned paint or applying the
paint too thinly.
The good thing is that chalking can usually be easily
removed by washing the surface with a solution consisting
of powdered laundry detergent and water. Simply apply the
solution, then take a clean clothe or nylon brush and
forcefully scrub the surface. If this doesn’t clear away
the chalking then the surface should be washed using
trisodiumphosphate (TSP). Be sure to follow the
manufacturer’s directions.
Unfortunately, TSP will most likely dull the finish and
you will have to apply a fresh coat of paint once the
chalking is removed. If your exterior is experiencing a
heavy case of chalking, you may want to use a "surface
bonder" in conjunction with a primer to enhance finish
coat adhesion. In any event, it is definitely worth your
time and money to properly prime and paint your siding in
the first place.
Rust: The main cause of rust stains are
deteriorated nail heads. When moisture and nails mix, nail
heads begin to rust and create spots on painted surfaces
on your home. This problem is caused by using uncoated
steel nails where excessive moisture exists under the
paint. It is suggested that rusting nails be removed and
replaced with new hot-dipped galvanized nails or
ceramic-coated construction screws because these fasteners
are rust-resistant.
Sometimes it isn’t practical or possible to remove rusty
nails. In such cases, the nail heads should be lightly
sanded with sandpaper and dabbed with a rust converter.
Also, all the surrounding siding that contains rust stains
should be treated with a shellac-based primer-sealer that
is designed to resist bleed-through. A finish coat of
paint can then be applied over the primer.
In addition to repairing and replacing the nail heads, you
should consider fighting the moisture problem that caused
the nails to rust in the first place. Do this by locating
the source of excessive moisture. Check for leakage from
the eaves, evaporation from nearby plumbing pipes, and
possible sweating caused by heat from a bathroom or
kitchen. If the source can be located, try eliminating the
problem by shutting off the condensation that causes the
moisture.
Cracks and Chips: Painted finishes often come down with
the cracks and chips illness. In painting terms it is
called "alligatoring." It gets this name because the
patterned cracking on the surface of the paint film
resembles the regular scales of an alligator. This
condition frequently occurs when hard-finish paint is
applied over soft paint or when flat paint is applied over
high-sheen paint. Alligatoring is a definite sign that
major prep work needs to be done on the exterior surface
and it usually involves scraping, sanding, filling and
priming.
Mildew: Mildew is a universal problem that results
in the formation of brown, black or gray spots or blotches
on the surface of paint or caulk due to the presence of
fungi on the surface of the paint. It typically begins to
grow on walls with a northern exposure and the underside
of eaves because these areas are damp and receive little
or no direct sunlight. Common causes for mildew growth are
when you use lower quality paint with an insufficient
amount of mildewcide, paint over a substrate or coating on
which mildew is present, or fail to prime bare wood before
painting.
To remove mildew you should first make sure that the
discoloration really is mildew, and not just dirt. You can
do this by applying a few drops of household bleach to it.
Wait about five minutes and then rinse the area. If the
dark color disappears then the problem is probably mildew.
You can remove all mildew by scrubbing with a diluted
household bleach solution made of one part bleach and
three parts water. Make sure to take the proper safety
precautions by wearing rubber gloves and eye protection.
Also, make sure to leave the bleach on the surface for
several minutes before rinsing.
You should then thoroughly clean the surface with a
detergent solution to remove dirt and other organic
material that mildew feed on. Do this by hand or with a
power washer and then rinse the surface again. Once it has
dried, apply one or two coats of top quality acrylic latex
paint. This type of paint contains extra mildewcide and
will resist mildew more efficiently than other paints. |
