ALLIGATORING Patterned cracking in the surface of the paint film
resembling the regular scales of an alligator. POSSIBLE
CAUSES:Application of an extremely hard, rigid coating, like an
alkyd enamel, over a more flexible coating, like a latex primer.
Application of a top coat before the undercoat is dry.Natural aging
of oil-based paints as temperatures fluctuate. The constant
expansion and contraction results in a loss of paint film
elasticity. SOLUTION:Old paint should be completely removed by
scraping and sanding the surface; a heat gun can be used to speed
work on large surfaces, but take care to avoid igniting paint or
substrate. The surface should be primed with high quality latex or
oil-based primer, then painted with a top quality exterior latex
paint.
BLISTERINGBubbles resulting from localized loss of adhesion, and
lifting of the paint film from the underlying surface.
POSSIBLE CAUSES:Painting a warm surface in direct
sunlight.Application of oil-based or alkyd paint over a damp or wet
surface.Moisture escaping through the exterior walls (less likely
with latex paint than with oil-based or alkyd paint).Exposure of
latex paint film to dew, high humidity or rain shortly after paint
has dried, especially if there was inadequate surface
preparation.SOLUTION:If blisters go down to the substrate: try to
remove the source of moisture. Repair loose caulking; consider
installing vents or exhaust fans. Remove blisters (see Below).If
blisters do not go all the way down to the substrate: remove them
by scraping, then sanding, prime bare wood and repaint with a
quality latex exterior paint.
CHALKINGFormation of fine powder on the surface of the paint
film during weathering which can cause color fading. Although some
degree of chalking is a normal, desirable way for a paint film to
wear, excessive film erosion can result from heavy
chalking.POSSIBLE CAUSES:Use of a low-grade, highly pigmented
paint.Use of an interior paint for an outdoor
application.SOLUTION:First, remove as much of the chalk residue as
possible, scrubbing with a stiff bristle brush (or wire brush on
masonry) and then rinse thoroughly; or use power washing equipment.
Check for any remaining chalk by running a hand over the surface
after it dries. If noticeable chalk is still present, apply a
quality oil-based or acrylic latex primer (or comparable sealer for
masonry), then repaint with a quality exterior coating; if little
or no chalk remains and the old paint is sound, no priming is
necessary.
CHALK RUN-DOWNThe washing down of chalk from an excessively
eroding paint onto another area below (a brick foundation, for
example), ruining its appearance (see Chalking). POSSIBLE
CAUSES:Use of a lower quality, highly pigmented paint. Use of an
interior paint for an outdoor application. Erosion of
factory-finished metal siding. SOLUTION: Remove as much of the
chalk residue as possible (see Chalking). Scrub any stained areas
with a stiff brush, using a detergent solution; rinse thoroughly.
In cases of severe staining, an acid wash may be necessary. Either
way, if the affected area dries to a different color, consider
painting it with a quality latex paint. Eroding aluminum siding
should be thoroughly cleaned (power washing recommended) before
painting with a quality exterior latex paint.
CRACKING / FLAKINGThe splitting of a dry paint film through at
least one coat, which will lead to complete failure of the paint.
Early on, the problem appears as hairline cracks; later, flaking of
paint chips occurs.POSSIBLE CAUSES:Use of a lower quality that has
inadequate adhesion and flexibility.Overthinning the paint or
spreading it too thin.Poor surface preparation, especially when the
paint is applied to bare wood without priming.Painting under cool
or windy conditions that make latex paint dry too fast.SOLUTION:It
may be possible to correct cracking that does not go down to the
substrate by removing the loose or flaking paint with a scraper or
wire brush, sanding to feather the edges, priming any bare spots
and repainting.If the cracking goes down to the substrate remove
all of the paint by scraping, sanding and/or use of a heat gun;
then prime and repaint with a quality exterior latex paint.
DIRT PICKUPAccumulation of dirt, dust particles and/or other
debris on the paint film; may resemble mildew.POSSIBLE CAUSES:Use
of a low quality paint, especially lower grades of satin or
semigloss.Soil splashing onto siding.Air pollution, car exhaust and
flying dust collecting on house body and horizontal
trim.SOLUTION:Wash off all surface dirt before priming and
painting, using a scrub brush and detergent solution, followed by a
thorough rinsing with a garden hose. Heavier dirt accumulations may
require the use of a power washer. While dirt pickup can't be
eliminated entirely, top quality exterior latex paints typically
offer superior dirt pickup resistance and washability. Also, higher
gloss paints are more resistant to dirt pickup than flat paints,
which are more porous and can more easily entrap dirt.
EFFLORESCENCE / MOTTLINGCrusty, white salt deposits, leached
from mortar or masonry as water passes through it.POSSIBLE
CAUSES:Failure to adequately prepare surface by removing all
previous efflorescence.Excess moisture escaping through the
exterior masonry walls from behind.SOLUTION:If excess moisture is
the cause, eliminate the source by repairing the roof, cleaning out
gutters and downspouts, and sealing any cracks in the masonry with
a high quality, water-based all-acrylic or siliconized acrylic
caulk. If moist air is originating inside the building, consider
installing vents or exhaust fans, especially in kitchen, bathroom
and laundry areas. Remove the efflorescence and all other loose
material with a wire brush, power brush or power washer; then
thoroughly rinse the surface. Apply a quality water-based or
solvent-based masonry sealer or primer, and allow it to dry
completely; then apply a coat of top quality exterior house paint,
masonry paint or elastomeric wall coating.
FADING / POOR COLOR RETENTIONPremature and/or excessive
lightening of the paint color, which often occurs on surfaces with
sunny southern exposure. Fading/poor color retention can also be a
result of chalking of the coating. POSSIBLE CAUSES: Use of an
interior grade of paint for an outdoor application.Use of a lower
quality paint, leading to rapid degradation (chalking) of the paint
film. Use of a paint color that is particularly vulnerable to UV
radiation (most notably certain bright reds, blues, and yellows).
Tinting a white paint not intended for tinting, or overtinting a
light or medium paint base. SOLUTION:When fading/poor color
retention is a result of chalking, it is necessary to remove as
much of the chalk as possible (see Chalking). In repainting, be
sure to use a quality exterior house paint in colors recommended
for exterior use.
FROSTINGA white, salt-like substance on the paint surface.
Frosting can occur on any paint color, but it is less noticeable on
white paint or lighter tints. On masonry, it can be mistaken for
efflorescence (see Efflorescence and Mottling). POSSIBLE CAUSES:
Forms mostly in protected areas (such as under eaves and on porch
ceilings) that do not receive the cleansing action of rain, dew and
other moisture. Use of dark-colored paints that have been
formulated with calcium carbonate extender. Application of a
dark-colored paint over a paint or primer containing calcium
carbonate extender. SOLUTION:Frosting can be a stubborn problem. It
often cannot be washed off readily. Moreover, the condition can
recur even as a bleed-through when a new top coat is applied. In
extreme cases, it can interfere with adhesion. The best remedy is
to remove the frosting by wirebrushing masonry or sanding wood
surfaces; rinse, then apply an alkyd-based primer before adding a
coat of high quality exterior paint.
LAPPNGAppearance of a denser color or ligher gloss where wet and
dry layers overlap during paint application. POSSIBLE CAUSES:
Failure to maintain a "wet edge" when applying paint.
SOLUTION:Maintain a wet edge when painting by applying paint toward
the unpainted area and then back into the just painted surface.
This technique (brushing from "wet to dry" rather than vice versa)
will produce a smooth uniform appearance. It is also wise to
minimize the area being painted, and plan for interruptions at a
natural break, such as a window, door or corner (especially
important when applying stain to bare wood). Alkyd paints generally
have superior wet edge properties.
MILDEWBlack, gray or brown areas of fungus growth on the surface
of paint or caulk.POSSIBLE CAUSES: Forms most often on areas that
tend to be damp, and receive little or no direct sunlight (walls
with a northerly exposure and the underside of eaves are
particularly vulnerable). Use of a lower quality paint, which may
have an insufficient amount of mildewcide. Failure to prime bare
wood before painting. Painting over a substrate or coating on which
mildew has not been removed. SOLUTION:Test to distinguish mildew
from dirt by applying a few drops of household bleach to the
discolored area; if it disappears, it is probably mildew. Treat the
mildew by applying a mixture of water and bleach, 3:1, and leave on
for 20 minutes, applying more as it dries. Wear goggles and rubber
gloves. Then scrub and rinse the area. Apply an exterior latex
primer, then a top-of- the-line exterior latex paint in flat,
satin, semigloss or gloss finish, depending on the desired
appearance.
NAILHEAD RUSTINGReddish-brown stains and spots on the paint
surface.POSSIBLE CAUSES: Non-galvanized iron nails have begun to
rust, causing bleed-through to the top coat. Non-galvanized iron
nails have not been countersunk and filled over. Galvanized
nailheads have begun to rust after sanding or excessive weathering.
SOLUTION: When painting new exterior construction where
non-galvanized nails have been used, it is advisable to first
countersink the nailheads, then caulk them with a top quality,
waterbased all-acrylic or siliconized acrylic caulk. Each nailhead
area should be spot primed, then painted with a quality latex
coating. When repainting exteriors where nailhead rusting has
occurred, wash off rust stains, sand the nailheads, then follow the
same surface preparation procedures as for new construction.
PAINT INCOMPATIBILITY Loss of adhesion where many old coats of
alkyd or oil-based paint receive a latex top coat. POSSIBLE CAUSES:
Use of water-based latex paint over more than three or four coats
of old alkyd or oil-based paint may cause the old paint to "lift
off" the substrate.
SOLUTION:Repaint using another coat of alkyd or oil-based paint.
Or completely remove the existing paint and prepare the surface -
cleaning, sanding and spot-priming where necessary - before
repainting with a top quality latex exterior paint.
PEELING Loss of paint due to poor adhesion. Where there is a
primer and top coat, or multiple coats of paint, peeling may
involve some or all coats.POSSIBLE CAUSES: Seepage of moisture
through uncaulked joints, worn caulk or leaks in roof or walls.
Excess moisture escaping through the exterior walls (more likely if
paint is oil-based).
Inadequate surface preparation.
Use of lower quality paint. Applying an oil-based paint over a
wet surface. Earlier blistering of paint (see Blistering).
SOLUTION: Try to identify and eliminate souce of moisture. Prepare
surface by removing all loose paint with scraper or stiff wire
brush, sand rough edges, and apply appropriate primer. Repaint with
a top quality acrylic latex exterior paint for best adhesion and
water resistance.
POOR ALKALI RESISTANCE Color loss and overall deterioration of
paint film on fresh masonry. POSSIBLE CAUSES: Oil-based paint or
vinyl acrylic latex paint was applied to new masonry that has not
cured for a full year. Fresh masonry is likely to contain lime
which is very alkaline. Until the lime has a chance to react with
carbon dioxide from the air, the alkalinity of the masonry remains
so high that it can attack the integrity of the paint film.
SOLUTION:Allow masonry surfaces to cure for at least 30 days,
and ideally for a full year, before painting. If this is not
possible, the painter should apply a quality, alkali-resistance
sealer or latex primer, followed by a top quality 100 percent
acrylic latex exterior paint. The acrylic binder in these paints
resists alkali attack.
POOR GALVANIZED METAL ADHESION Paint that has lost its adhesion
to a galvanized metal substrate. POSSIBLE CAUSES:Improper surface
preparation, such as inadequate rust removal.
Failure to apply a primer before application of an oil-based or
vinyl latex paint.
Failure to sand baked-on enamel finishes or glossy surfaces
before painting. SOLUTION: Any rust on the metal should be removed
with a wire brush; then, an acrylic latex corrosion-inhibitive
primer should be applied (one coat is usually sufficient).
Previously painted galvanized metal that is completely rust-free
can be painted without applying a primer. A latex metal primer
should be applied to unpainted galvanized metal, followed by a top
quality exterior acrylic latex paint.
POOR GLOSS RETENTION Deterioration of the paint film, resulting
in execessive or rapid loss of luster of the top coat. POSSIBLE
CAUSES:Use of an interior paint outdoors. Use of a lower quality
paint.
Use of a gloss alkyd or oil-based paint in areas of direct
sunlight. SOLUTION: Direct sunshine can degrade the binder and
pigment of a paint, causing it to chalk and lose its gloss. While
all types of paint will lose some degree of luster over tim, lower
quality paints will generally lose gloss much earlier than better
grades. The binder in top quality acrylic latex paints is
especially resistance to UV radiation, while oil and alkyd binders
actually absorb the radiation, causing the binders to break down.
Surface preparation for a coating showing poor gloss retention
should be similar to that used for chalking surfaces (see
Chalking).
SURFACTANT LEACHING Concentration of water-soluble ingredients
on latex paint, creating a blotchy, sometimes glossy appearance,
often with a tan or brownish cast. More likely with tinted paints
than with white or factory-colored paints. POSSIBLE CAUSES:
Painting in cool, humid conditions or just before they occur. The
longer drying time allows the paint's water-soluble ingredients -
which would normally evaporate, or be leached out by rain or dew -
to rise to the surface before paint thoroughly dries. Mist, dew or
other moisture drying on the painted surface shortly after it has
dried.
SOLUTION: Avoid painting in the late afternoon if cool, damp
conditions are expected in the evening or overnight. If the problem
occurs in the first day or so after the paint is applied, the
water-soluble material can sometimes be rinsed off rather easily.
Fortunately, even more stubborn cases will generally weather off in
a month or so. Sufactant leaching should not affect the ultimate
durability of the coating.
TANNIN STAINING
Brownish or tan discoloration on the paint surface due to
migration of tannins from the substrate through the paint film.
Typically occurs on "staining woods," such as redwood, cedar and
mahogany, or over painted knots in certain other wood species.
POSSIBLE CAUSES: Failure to adequately prime and seal the surface
before applying the paint. Use of a primer that is not sufficiently
stain-resistant. Excess moisture escaping through the exterior
walls, which can carry the stain to the paint surface. SOLUTION:
Correct any possible sources of excess moisture (see Efflorescence
and Mottling). After thoroughly cleaning the surface, apply a high
quality stain- resistant oil-based or acrylic latex primer.
Oil-based stain-resistant primers are the best type to use on
severely staining boards. In extreme cases, a second coat of primer
can be applied after the first has died thoroughly. Finish with a
top quality latex paint.
VINYL SIDING WARP Warping or buckling of vinyl siding panels
that have been repainted. POSSIBLE CAUSES:Most likely cause is that
vinyl siding was painted with a darker color paint than the
original color. Dark paint tends to absorb the heat of the sun,
transferring it to the substrate. When vinyl siding expands
dramatically, it is not able to contract to its original
dimensions. SOLUTION:Paint vinyl siding in a shade no darker than
the original. Whites, off-whites, pastels and other very light
colors are good choices. Top quality acrylic latex paint is the
best type of paint to use on vinyl siding, because the superior
flexibility of the paint film enables it to withstand the stress of
expansion and contraction cycles cause by outdoor temperature
changes. Siding that has warped or buckled should be assessed by a
siding or home repaint contractor to determine the best remedy. The
siding may have to be replaced.
WAX BLEED Stains that come from waxy substance in the
reconstituted wood products used to make hardboard siding. When the
substrate is painted, these staining substances bleed through the
paint; they can even bleed through some ordinary primers, possibly
causing dirt pickup, mildew and/or poor paint adhesion (see Dirt
Pickup and Mildew). POSSIBLE CAUSES:Failure to apply a proper
primer to hardboard before applying the top coat.
Allowing hardboard siding to weather before being painted.
SOLUTION: To treat or prevent, apply a quality exterior acrylic
latex primer; follow with a coat of high quality exterior acrylic
latex paint. The American Hardboard Association recommends two coat
of top quality acrylic exterior house paint for best results. Some
hardboard grades have adequate factory primer and need only a
quality paint applied. Low quality, highly pigmented flat paints
are more prone to wax bleed than are higher quality paints.
WRINKLING A rough, crinkled paint surface occurring when paint
forms a "skin." POSSIBLE CAUSES: Paint applied too thickly (more
likely when using alkyd or oil-based paints).
Painting a hot surface or in very hot weather. Exposure of
uncured paint to rain, dew, fog or high humidity levels. Applying
top coat of paint to insufficiently dried first coat. Painting over
contaminated surface (e.g., dirt or wax). SOLUTION: Scrape or sand
substrate to remove wrinkled coating. Repaint, applying an even
coat of top quality exterior paint. Make sure the first coat or
primer is dry before applying the top coat. Apply paints at the
manufacturer's recommended spread rate (two coats at the
recommended spread rate are better than one thick coat). When
painting during extremely hot, cool or damp weather, allow extra
time for the paint to dry completely. Paint Defects
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