Bubbles resulting from localized loss of adhesion and lifting of the paint film from the underlying surface.
- Applying oil-based or alkyd paint over a damp or wet surface.
- Moisture seeping into the home through the exterior walls (less likely with latex paint).
- Exposure of latex paint film to high humidity or moisture shortly after paint has dried, especially if there was inadequate surface preparation.
- If blisters do not go all the way down to the substrate: Remove blisters by scraping and sanding, and repaint with a quality acrylic latex interior paint.
- If blisters go down to the substrate: Remove the source of moisture, if possible. Repair loose caulking; consider installing vents or exhaust fans. Remove blisters as above, remembering to prime before applying the top coat.
Undesirable sticking together of two painted surfaces when pressed together (e.g, a door sticking to the jamb).
- Not allowing sufficient dry time for the coating before closing doors or windows.
- Use of low quality semigloss or gloss paints.
Solution: Use top quality semigloss or gloss acrylic latex paint. Low quality latex paints can have poor block resistance especially in warm, damp conditions. Follow paint label instructions regarding dry times. Acrylic latex paints generally have better early block resistance than vinyl latex paints, or alkyd or oil-based paints; however, alkyds develop superior block resistance over time. Application of talcum powder can relieve persistent blocking.
Increase in gloss or sheen of paint film when subjected to rubbing, scrubbing or having an object brush up against it.
- Use of flat paint in highly trafficked areas, where a higher sheen level would be desirable.
- Frequent washing and spot cleaning.
- Objects (furniture, for example) rubbing against walls.
- Use of lower grades of paint with poor stain and scrub resistance (see POOR STAIN RESISTANCE and POOR SCRUB RESISTANCE).
Solution: Paint heavy wear areas that require regular cleaning (e.g., doors, window sills, and trim) with a top quality latex paint, because this type of paint offers both durability and easier cleaning capability. In high traffic areas, choose a semigloss or gloss rather than a flat sheen level. Clean painted surfaces with a soft cloth or sponge and non-abrasive cleaners; rinse with clean water.
Loss of caulk’s initial adhesion and flexibility, causing it to crack and/or pull away from the surfaces to which it is applied.
- Use of lower quality caulk.
- Use of wrong type of caulk for particular application (e.g., using latex or vinyl caulk in areas where there is prolonged contact with water or considerable movement of the caulked surfaces).
Solution: Use a top quality water-based all-acrylic or siliconized acrylic caulk if prolonged contact with water is not anticipated. These caulks are flexible enough to adapt to minor fluctuations in the substrate, stretching in gaps that widen slightly over time. They also adhere to a wide range of interior building materials, including wood, ceramic tile, concrete, glass, plaster, bare aluminum, brick and plastic – even in areas where moisture is present. Note: Silicone caulk should not be painted.
CRACKING / FLAKING
The splitting of a dry paint film through at least one coat as a result of aging, which ultimately will lead to complete failure of the paint. In its early stages, the problem appears as hairline cracks; in its later stages, flaking occurs.
- Use of lower quality paint that has inadequate adhesion and flexibility.
- Overthinning or overspreading the paint.
- Inadequate surface preparation, or applying the paint to bare wood without first applying a primer.
- Excessive hardening and embrittlement of alkyd paint as the paint job ages.
Solution: Remove loose and flaking paint with a scraper or wire brush, sanding the surface and feathering the edges. If the flaking occurs in multiple layers of paint, use of a filler may be necessary. Prime bare wood areas before painting. Use of a top quality primer and top coat should prevent a recurrence of the problem.
FOAMING / CRATERING
Formation of bubbles (foaming) and resulting small, round concave depressions (Cratering) when bubbles break in a paint film, during paint application and drying.
- Shaking a partially filled can of paint.
- Use of low quality paint or very old latex paint.
- Applying (especially rolling) paint too rapidly.
- Use of a roller cover with wrong nap length.
- Excessive rolling or brushing of the paint.
- Applying a gloss or semigloss paint over a porous surface.
Solution: All paints will foam to some degree during application; however, higher quality paints are formulated so the bubbles break while the paint is still wet, allowing for good flow and appearance. Avoid excessive rolling or brushing of the paint or using paint that is more than a year old. Apply gloss and semigloss paints with a short nap roller, and apply an appropriate sealer or primer before using such paint over a porous surface. Problem areas should be sanded before repainting.
Appearance of a denser color or increased gloss where wet and dry layers overlap during paint application.
- Failure to maintain a “wet edge” when painting.
- Use of a low solids “economy” 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 or rolling from “wet to dry”, rather than vice versa) will produce a smooth, uniform appearance. It is also wise to work in manageable-size areas; plan for interruptions at a natural break, such as a window, door or corner. Using a top quality acrylic latex paint makes it easier to avoid lapping problems because higher solids (pigments and binder) content makes lapped areas less noticeable. If substrate is very porous, it may need a primer/sealer to prevent paint from drying too quickly and reducing wet edge time. Alkyd paints generally have superior wet edge properties.
Black, gray or brown spots or areas on the surface of paint or caulk.
Possible Causes: Forms most often on areas that tend to be damp, or receive little or no direct sunlight (e.g., bathrooms, kitchens and laundry rooms).
Use of an alkyd or oil-based paint, or lower quality latex paint.
Failure to prime bare wood surface before applying the paint.
Painting over a substrate or coating on which mildew has not been removed.
Solution: Test for mildew by applying a few drops of household bleach to the area; if it is bleached away, the discolorant is probably mildew. Remove all mildew from the surface by scrubbing with a diluted household bleach solution (one part bleach, three parts water), while wearing rubber gloves and eye protection. Rinse thoroughly. To protect against mildew, use a top quality latex paint, and clean when necessary with bleach/detergent solution. Consider installing an exhaust fan in high moisture areas.
Deep, irregular cracks resembling dried mud in dry paint film.
- Paint is applied too thickly, usually over a porous surface.
- Paint is applied too thickly, to improve inherent poor hiding (coverage) of a lower quality paint.
- Paint is allowed to build up in corners upon application.
Solution: Remove coating by scraping and sanding. Prime and repaint, using a top quality latex paint. Mud-cracked areas can also be repaired by sanding the surface smooth before repainting with a top quality latex paint. This type of paint is likely to prevent recurrence of mud cracking, because it is relatively more flexible than alkyd paint, oil-based paint and ordinary latex paint. Quality paints have a higher solids content, which reduces the tendency to mud crack. They also have very good application and hiding properties, which minimize the tendency to apply too thick a coat of paint.
An effect of non-uniform color that can appear when a wall is painted with a roller, but is brushed at the corners. The brushed areas generally appear darker, resembling the “frame” of a “picture”. Also, sprayed areas may be darker than neighboring sections that are brushed or rolled. Picture framing can also refer to sheen effects.
- Usually a hiding (coverage) effect. Brushing will generally result in lower spread rates than rolling, producing a thicker film and more hiding.
- Adding colorant to a non-tintable paint or using the wrong type or level of colorant.
Solution: Make sure that spread rates with brushes and rollers are similar. Don’t cut in the entire room before roller coating. Work in smaller sections of the room to maintain a “wet edge”. With tinted paints, be sure the correct colorant-base combinations are used. Factory colors, as well as in-store tints, should be thoroughly shaken at time of sale.
POOR FLOW / LEVELING
Failure of paint to dry to a smooth film, resulting in unsightly brush and roller marks after the paint dries.
- Use of lower quality paint.
- Application of additional paint to “touch-up” partially dried painted areas.
- Re-brushing or re-rolling partially dried painted areas.
- Use of the wrong type of roller cover or poor quality brush.
Solution: Use top quality latex paints, which are generally formulated with ingredients that enhance paint flow. Brush and roller marks thus tend to “flow out” and form a smooth film. When using a roller, be sure to use a cover with the recommended nap length for the type of paint being used. Use of a high quality brush is important; a poor brush can result in bad flow and leveling with any paint.
Failure of dried paint to obscure or “hide” the surface to which it is applied.
- Use of a low quality paint.
- Use of a low quality tools/wrong roller cover.
- Use of an improper combination of tinting base and tinting color.
- Poor flow and leveling (see POOR FLOW / LEVELING)
- Use of paint that is much lighter in color than the substrate, or that primarily contains low-hiding organic pigments.
- Application of paint at a higher spread rate than recommended.
Solution: If the substrate is significantly darker or is a patterned wallpaper, it should be primed before applying a top coat. Use a top quality paint for better hiding and flow. Use quality tools; use the recommended roller nap, if rolling. Follow manufacturer’s recommendation on spread rate; if using tinted paint, use the correct tinting base. Where a low-hiding organic color must be used, apply a primer first.
POOR PRINT RESISTANCE
Tendency of paint film to take on the imprint of an object that is placed on it (e.g., a shelf, table, window sill or countertop with books, dishes, and other objects on them).
- Use of low quality semigloss or gloss paint.
- Putting a painted surface back into use before paint has fully dried.
Solution: Use a top quality acrylic semigloss or gloss latex paint. Low quality latex semigloss and gloss paints can have poor print resistance, especially in warm, damp conditions. Acrylic latex paints generally have better print resistance than vinyl latex paints. Fully cured alkyd paints also have excellent print resistance. Make sure the recommended “cure” time is allowed for the paint before it is put into service. Cool or humid conditions require more curing time.
POOR SCRUB RESISTANCE
Wearing away or removal of the paint film when scrubbed with a brush, sponge, or cloth.
- Choosing the wrong sheen for the area.
- Use of a lower quality paint.
- Use of an overly aggressive scrub medium (see BURNISHING).
- Inadequate dry time allowed after application of the paint before washing it.
Solution: Areas that need frequent cleaning require a high quality paint formulated to provide such performance. High traffic areas may require a semigloss or gloss paint rather than a flat paint to provide good scrub resistance. Allow adequate dry time, as scrub resistance will not fully develop until the paint is thoroughly cured. Typically, this will be one week. Try washing the painted surface with the least abrasive material and mildest detergent first.
POOR SHEEN UNIFORMITY
Shiny spots or dull spots (also known as “flashing”) on a painted surface; uneven gloss.
- Uneven spread rate.
- Failure to properly prime a porous surface, or surface with varying degrees or porosity.
- Poor application resulting in lapping (see LAPPING).
Solution: New substrates should be primed/sealed before applying the top coat to ensure a uniformity porous surface. Without the use of a primer or sealer, a second coat of paint will more likely be needed. Make sure to apply paint from “wet to dry” to prevent lapping. Often, applying an additional coat will even out sheen irregularities.
POOR STAIN RESISTANCE
Failure of the paint to resist absorption of dirt and stains.
- Use of lower quality paint that is porous in nature.
- Application of paint to unprimed substrate.
Solution: Higher quality latex paints contain more binder, which helps prevent stains from penetrating the painted surface, allowing for easy removal. Priming new surfaces provides maximum film thickness of a premium top coat, providing very good stain removability.
ROLLER MARKS / “STIPPLE”
Unintentional textured pattern left in the paint by the roller.
- Use of incorrect roller cover.
- Use of lower grades of paint.
- Use of low quality roller.
- Use of incorrect rolling technique.
Solution: Use the proper roller cover; avoid too long a nap for the paint and the substrate. Use quality rollers to ensure adequate film thickness and uniformity. High quality paints tend to roll on more evenly due to their higher solids content and leveling properties. Pre-dampen roller covers used with latex paint; shake out excess water. Don’t let paint build up at roller ends. Begin rolling at a corner near the ceiling and work down the wall in three-foot square sections. Spread the paint in a zigzag “M” or “W” pattern, beginning with an upward stroke to minimize splatter; then, without lifting the roller from the surface, fill in the zigzag pattern with even, parallel strokes.
Tendency of a roller to throw off small droplets of paints during application.
- Use of exterior paint on an interior surface.
- Use of lower grades of latex paints.
Solution: Higher quality paints are formulated to minimize spattering. Using high quality rollers which have proper resiliency further reduces spattering. In some cases, a quality wall paint may be preferred for ceiling work, for maximum spatter resistance. Overloading the roller with paint will result in excess spatter, as will overworking the paint once it is applied to a substrate. Working in three-feet square sections, applying the paint in a zigzag “M” or “W” pattern and then filling in the pattern will also lessen the likelihood of spattering.
Downward “drooping” movement of the paint film immediately after application resulting in an uneven coating.
- Application of a heavy coat of paint.
- Application in excessively humid and/or cool conditions.
- Application of overthinned paint.
- Airless spraying with the gun too close to the substrate being painted.
Solution: If paint is still wet, immediately brush out or re-roll to redistribute the excess evenly. If the paint has dried, sand and reapply a new coat of top quality paint. Correct any unfavorable conditions; Do not thin the paint; avoid cool or humid conditions; sand glossy surfaces. Paint should be applied at its recommended spread rate; avoid “heaping on” the paint. Two coats of paint at the recommended spread rate are better than one heavy coat, which can also lead to sagging. Consider removing doors to paint them supported horizontally.
Concentration of water-soluble ingredients on the surface of a latex paint, typically on a ceiling surface in rooms that have high humidity (e.g., shower, bathroom, kitchen); may be evident as tan or brown spots or areas, and can sometimes be glossy, soapy, or sticky.
Possible Causes: All latex paint formulas will exhibit this tendency to some extent if applied in areas that become humid (bathrooms, for example), especially in ceiling areas.
Solution: Wash the affected area with soap and water, and rinse. Problem may occur once or twice again before leachable material is completely removed. When paint is applied in a bathroom, it is helpful to have it dry thoroughly before using the shower. Remove all staining before repainting.
A rough, crinkled paint surface, which occurs when uncured paint forms a “skin”.
- Paint is applied too thickly (more likely when using alkyd or oil-based paints).
- Painting during extremely hot weather or cool damp weather, which causes the paint film to dry faster on top than on the bottom.
- Exposing uncured paint to high humidity levels.
- Painting over contaminated surface (e.g., dirt or wax)
Solution: Scrape or sand substrate to remove wrinkled coating. If using a primer, allow it to dry completely before applying top coat. Repaint (avoiding temperature/humidity extremes), applying an even coat of top quality interior paint.
Development of a yellow cast in aging paint; most noticeable in the dried films of white paints or clear varnishes.
- Oxidation of alkyd or oil-based paint or varnish.
- Heat from stoves, radiators and heating ducts.
- Lack of light (e.g., behind pictures or appliances, inside closets, etc.)
Solution: Top quality paints do not tend to yellow, nor does non-yellowing varnish. Alkyd paints, because of their curing mechanism, do tend to yellow, particularly in areas that are protected from sunlight.
REMEDIES FOR COMMON PAINT PROBLEMS
Patterned cracking in the surface of the paint film resembling the regular scales of an alligator.
- 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 a high quality latex or oil-based primer, then painted with a top quality exterior latex paint.
Bubbles resulting from localized loss of adhesion and lifting of the paint film from the underlying surface.
- 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.
- If blisters go down to the substrate, try to remove the source of moisture. Repair loose caulking; consider installing an exhaust fan. Remove blisters (see below).
- If blisters do not go all the way down to the substrate, remove them by scraping, then sanding, prime any bare wood and repaint with a quality exterior paint.
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 in heavy chalking.
- 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, using a stiff bristle brush (or wire brush on masonry) and then rinse thoroughly with a garden hose; 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).
- 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.
- 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.
- 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.
Accumulation of dirt, dust particles and/or other debris on the paint film; may resemble mildew.
- 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. If unsure whether the problem is dirt or mildew, conduct a simple spot-test (see MILDEW). Clean off dirt with 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.
- Failure to adequately prepare surface by removing all previous efflorescence.
- Excess moisture escaping through the exterior masonry walls from the inside.
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 wire brush, power brush, or power washer; then thoroughly rinse the surface. Apply a quality water-based or solvent-based masonry sealer 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.
- 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.
A white, salt-like substance on the paint surface. Frosting can occur on any paint color, but is less noticeable on white paint or light tints. On masonry, it can be mistaken for efflorescence (see EFFLORESCENCE/MOTTLING).
- Forms mostly in protected areas (such as under eaves and on open 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.
Appearance of a denser color or higher 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 help 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.
Black, gray or brown areas on the surface of paint or caulk.
- 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 for mildew by applying a few drops of household bleach to the discolored area; if it disappears, it is probably mildew. Remove all mildew from the surface by scrubbing with a diluted household bleach solution (one part bleach, three parts water); wear rubber gloves and eye protection. Power washing is also an option. Rinse thoroughly, prime any bare wood, then apply one or two coats of top quality exterior paint, which typically contains more mildewcide.
Reddish-brown stains on the paint surface.
- 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, water-based 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.
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.
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.
- 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 cause of moisture (see EFFLORESCENCE/MOTTLING). Prepare surface by removing all loose paint with scraper or wire brush, sand rough surfaces, prime bare wood. 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-resistant 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.
- 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-resistant primer should be applied (one coat is usually sufficient). New or previously painted galvanized metal that is completely rust-free can be painted with a top quality acrylic latex paint without applying a primer; however, a metal primer should always be applied to unpainted galvanized metal before applying an oil-based or vinyl latex top coat.
POOR GLOSS RETENTION
Deterioration of the paint film, resulting in excessive or rapid loss of luster of the top coat.
- 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 time, lower quality paints will generally lose gloss much earlier than better grades. The binder in top quality acrylic latex paint is especially resistant 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 in chalking surfaces (see CHALKING).
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.
- 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 the 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. Surfactant leaching should not affect the ultimate durability of the coating.
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.
- 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/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 dried 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 repainted 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.
- 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 caused by outdoor temperature changes.
- Siding that has warped or buckled should be assessed by a siding or home repair contractor to determine the best remedy. The siding may have to be replaced.
Stains that come from waxy substances 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).
- 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 coats 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.
A rough, crinkled paint surface occurring when paint forms a “skin”.
- 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 rare are better than one thick coat). When painting during extremely hot, cool, or damp weather, allow extra time for the paint to dry completely.