Understanding the primary causes of paint
failures will help a homeowner prevent future paint problems.
The primary causes of paint failures are moisture, inadequate
surface prep, the improper application of paints, the Sun, and
weathering. Homeowners should be aware that most paint
failures are related to moisture and inadequate surface
preparation. Please refer to the Surfaces section for more
information concerning surfaces and surface preparation. Some
of the more common paint failures are listed below in
alphabetical order with recommendations for their prevention.
Alligatoring is cracked paint that resembles alligator skin,
and is generally found on wood surfaces. Alligatoring occurs
when paint can not adhere to a glossy surface, when a second
coat of paint is applied over an inadequately dried first coat
of paint, weather aging, excessive coats of paint, or when the
finish coat expands and contracts at a greater extent that any
underlying coats. Paint must be completely removed when
alligatoring has occurred to ensure an even and uniform
finish. Wood surfaces should be primed with a top quality
alkyd primer and acrylic latex finish.
Bleeding is an unsightly surface discolouration commonly found
on exterior wood surfaces and hardboard siding, ceilings,
repainted wallpaper, or when light coloured paint is applied
over dark coloured paint. The causes of bleeding are moisture
and water soluble dyes located within wood surfaces and
wallpaper, and inadequate priming of surfaces. Bleeding on
hardboard siding is caused by wax. The removal of any
excessive water source is essential before any surface
preparation can be completed. Exterior wood surfaces should be
primed with top quality alkyd based primers and finished with
top quality acrylic latex paints. Interior surfaces should be
primed with either a top quality alkyd based or acrylic latex
based stain blocking primer, and finished with a top quality
acrylic latex finish paint.
Fresh paint applied in direct sunlight, and moisture, causes
paint to blister. Surfaces that are heated by the Sun and
become hot can prematurely dry new paint, causing blistering.
This is more common with dark or dramatic colours because they,
in addition to surfaces, absorb heat. Heat blistering will
have a layer of paint under the blister if the surface is
being repainted. Trapped moisture in walls or behind surfaces
will eventually try to escape through painted surfaces, also
causing blistering. Moisture blistering will reveal a bare
surface under the blister. Blistering surfaces should be
scraped and sanded smooth, primed with a top quality alkyd or
acrylic latex primer, and finished with a top quality acrylic
latex finish paint. If moisture blistering occurs on a
repainted surface, spot priming of bare spots will be
necessary to ensure a uniform and even finish before the final
priming and painting is completed.
Chalking is the weathered powder found on exterior painted
surfaces and is a normal way for paint to weather away.
However, premature chalking can be caused by inadequate
priming or thin paint. Homeowners should be aware that
chalking on siding located above masonry will run during rainy
weather causing the masonry to stain. Once a chalked surfaced
is pressured washed clean and prepared for painting, one coat
of a top quality alkyd primer and one coat of a top quality
acrylic latex finish paint is highly recommended for the
prevention of future excess chalking.
Checking and Cracking
Checking is an early form of cracking and occurs when paint
begins to loose elasticity, forming narrow breaks on the
painted surface. These breaks later swell and become cracks.
Checking and cracking are found on wood surfaces with multiple
layers of paint, or plywood. Checked or cracked paint should
be completely removed from surfaces before repainting.
Properly prepared wood surfaces should be primed with a top
quality alkyd primer and finished with a top quality acrylic
latex finish paint.
Efflorescence is a white salty substance that forms on masonry
and plaster due to moisture migrating through the surface. If
left untreated for long periods of time, it will become hard
and crusty. Any source of excessive moisture must be
eliminated and the surface must be cleaned by scraping or wire
brushing, and surfaces must be repaired where applicable
before priming and painting. Surfaces can be painted with top
quality alkyd or acrylic latex based primers and paints that
are alkaline resistant.
Fading is caused by the natural weathering due to the
ultraviolet rays of the Sun. Chalking pigment, alkali from
masonry, and tint intended for interior based paints but used
on exterior surfaces, will cause paint to fade prematurely.
Hatbanding is caused by the over cutting in of interior walls,
ceilings , and trim corners, and the use of excessively long
roller naps. It occurs when wet paint is applied over dry
paint. Hatbanding is very noticeable with dark and dramatic
interior colours and sheens. Using small nap rollers and
applying a thin brush coat of paint will help eliminate
Lap marks are due to the inadequate application of coatings.
They are mostly seen on exterior surfaces. If a homeowner or
contractor is brush painting siding, the paint must be applied
horizontally from one end to the other without stopping. If
the homeowner or contractor stops in the middle or the paint
dries to fast, when the application of the paint to the
surface is continued, a lap mark forms where the paint
overlapped. This is a major reason why coatings should never
be applied in direct sunlight. Coatings should be applied in
shady area's in warm months and homeowners and contractors
should stay ahead of the Sun in cooler months. Staying ahead
of the Sun will allow it to come around and dry the area most
Mildew is a fungus that grows best in a warm humid climate and
is often found in shaded area’s, but not limited to shaded
area’s. Mildew can appear in a variety of colours and prefers
painted surfaces because of the nutrients that paints provide.
These same nutrients float through the air and land on painted
surfaces and become food. Mildew grows faster on flat surfaces
than on glossy surfaces, and is attracted to linseed oil based
products that contain no mildewcide. Most paints and stains
come already made with mildewcide included. However,
mildewcide can be added to paints and stains that do not
contain one. Mildew can be effectively cleaned with a 3 to 1
ratio of water to bleach. A much stronger solution maybe
necessary in extreme cases of neglect. Proper surface
preparation and cleaning are crucial for mildew prevention, in
addition to using a top quality primer and acrylic latex
finish paint. Acrylic latex finish paints are the most mildew
resistant. Painting contractors who perform quality surface
preparation and painting are a homeowners best ally in
preventing the growth of mildew.
Peeling occurs on a variety of surfaces and is directly linked
to moisture and inadequate surface preparation. Understanding
different surfaces and how they react to moisture and coatings
will greatly reduce the risk of this common paint problem.
Rusting occurs when metal is exposed to moisture and oxygen.
Any metal surfaces should be completely sealed with a rust
inhibited primer. If rust appears through painted surfaces, it
should be wire brushed to bare metal, or treated with a
coating that will harden it. Two coats of a top quality rust
inhibited alkyd or acrylic latex primer should be applied to
metal surfaces once the rust is treated or wire brushed away.
Rusty nails that bleed through surfaces should be reset,
coated with a top quality rust inhibited primer, caulked,
primed, and painted with top quality coatings.
Sagging and Running
Sagging and Running can occur when paint is applied over
glossy surfaces, excessive thinning, too much paint, or paint
being applied to a dirty surface. Proper application of paints
and surface preparation will eliminate sags and runs.
Wrinkling is caused when thick paint is not brushed out and
the under part remains wet, but the surface layer dries. Avoid
covering surfaces with one thick coat when two are required.