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.
• Often cross grain crazing means paint build-up is the culprit.

SOLUTION:

• Old paint should be completely stripped by scraping and sanding the surface; a heat gun or infra-red heater 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 linseed oil-based primer, then painted with a top quality exterior latex paint.

BLISTERING

Bubbles 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.

CHALKING

Formation 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.

The 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 / FLAKING

The 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 paint 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 PICKUP

Accumulation 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 / MOTTLING

Crusty, 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 RETENTION

Premature 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.

FROSTING

A 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.

LAPPNG

Appearance 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.

MILDEW

Black, 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 RUSTING

Reddish-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. Where there are many layers of old paint (say 1/16” or about 15 coats), two peeling problems can result: peeling and cracking.

POSSIBLE CAUSES:

• Seepage of moisture through un-caulked 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 or damp surface.
• Earlier blistering of paint (see Blistering).
• Old paint gets brittle, the contraction of a new coat of paint as it dries and the movement of the newer more flexible paints with the temperature changes can crack and peel the older coats.

SOLUTION:

• Try to identify and eliminate source of moisture. The most common source of dampness is professional painters priming and painting before the surface is completely dry. Every morning the walls are covered with dew, and every morning the professionals are out painting wet walls.
• 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. For best results strip old paint completely and start fresh with bright freshly sanded and dry old wood.

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 is applied in direct sunlight. Sun can cause the top of the paint to bake dry while the under layer remains moist. When the under layer does finally dry it shrinks and can cause wrinkles in the upper layers.

SOLUTION:

• Scrape or sand substrate to remove wrinkled coating. Hand scrub with TSP solution hot to warm water. Use a stiff brush and wash from the bottom of the house up, so residue does not streak down the siding. After scrubbing an area, rinse immediately with a garden hose before it has a chance to dry.
• 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.