Paint - Defects

Defects

* Starting at the ceiling, cut in 2 inch strip with a brush. Continue with the brush to cut in 2 inch strips in corners, around windows, doors, cabinets and baseboards. Note - there are tools available at your paint retail outlets that help make this "edging" job easier. Other "tricks" include sliding the roller cover off the holder slightly so the rollers edge gets closer to ceiling, window or door.
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WallsSwitch to a roller and paint in a vertical direction using a zigzag pattern. Push the roller upward on the first stroke, then form an "M" pattern to evenly distribute the paint on the roller. (working in 3 ft sections is recommended). Fill in the "M" pattern without reloading the roller until you have complete coverage of the area. Continue with this approach until the wall is finished. Touching up spots you missed when the paint is wet will help minimize sheen potential sheen differences.

Most manufacturers recommend that when you finish one wall, make sure you have enough paint to complete the next entire wall. Starting with another can of paint in the middle of a wall can result in slightly different colors, which will be perceptible side by side, but not wall to wall.

Common Defects and Problem

Interior

Blistering

Bubbles resulting from localized loss of adhesion, and lifting of the paint film from the underlying surface.

POSSIBLE CAUSES:

* 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.

SOLUTION:

* 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.






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Example of blocking

Blocking

Undesirable sticking together of two painted surfaces when pressed together (e.g., a door sticking to the jamb).

POSSIBLE CAUSES:

* 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 then 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.

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.

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POSSIBLE CAUSES:
o Use of lower quality paint that has inadequate adhesion and flexibility.Overthinning or overspreading the paint.
o 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:
o 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 repainting. Use of a top quality primer and top coat should prevent a recurrence of the problem.

Mildew

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.

Yellowing

Development of a yellow cast in aging paint; most noticeable in the dried films of white paints or clear varnishes.

POSSIBLE CAUSES:

* 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 latex 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.

Wrinkling

A rough, crinkled paint surface, which occurs when uncured paint forms a "skin."

POSSIBLE CAUSES:

* Paint 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 a 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.

Surfacant leaching

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.

Sagging

Downward "drooping" movement of the paint film immediately after application, resulting in an uneven coating.

POSSIBLE CAUSE:

* 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 the 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.

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.

POSSIBLE CAUSES:

* Shaking a partially filled can of paint.
* Use of low quality paint or very old latex paints. ¥ 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.

Exterior

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.

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.

Fading

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.

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.

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.

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.

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.

Efflourescence/Motting

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.

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 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.

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.

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.

Why is surface preparation important?

Inadequate surface preparation is the biggest single reason why paint failures occur. Depending on the condition of the surfaces being painted, proper surface preparation might include cleaning, repairing, patching, sanding, masking and priming. Each of these steps are described below in greater detail, for both interior and exterior painting:


When should I repair, patch, sand and mask?

Note: If you're going to be doing any sanding, scraping or wirebrushing, it's best to use the appropriate safety equipment, like goggles, gloves, dust masks, etc.

* Check for rotting, degraded or otherwise damaged surfaces, and repair or replace where necessary; the paint needs a stable substrate for good adhesion.
* Old, weathered wood should be scraped, wirebrushed and/or sanded to remove loose wood fibers and create a sound substrate for better primer and paint adhesion.
* New wood should be sanded with a fine grit sandpaper; the sanding should be done with the grain, not against it. New wood surfaces should also be lightly sanded after priming, to remove any wood fibers that were raised by the primer.
* All surfaces to be painted should be checked for cracks, gaps, dents and holes; these areas should be patched with spackling paste or caulking. Be sure to check the following areas:
o Around window or door frames (these areas get a lot of wear and tear!).
o Where siding meets the foundation or masonry.
o Where the siding forms corner joints.
o Around vent ducts and other openings for plumbing, wiring, or cable.
* When using spackling paste, apply it so it's slightly higher than the surrounding surface. Once dry, sand the patched area so it's smooth and level with the surrounding surface.
* Check existing caulk and window glazing; remove sections that are inflexible, cracked or pulled away from the substrate, and replace them (be sure to clean these areas and let them dry before putting in new caulk or glazing).
* Check gutters and downspouts, and replace them if they're badly rusted. Otherwise, use a wire brush, scraper or power sander to remove any rust and/or loose paint. Then, use an all-purpose cleaner to remove any dirt, and rinse the surface thoroughly.
* Before painting over a surface that was previously painted with a glossy paint, use fine or medium grit sandpaper to scuff up and roughen the surface, so the paint will adhere (be sure to do all sanding in one direction; if a circular motion is used, the scratches may show through the topcoat). A chemical deglosser may also be used.
* If there's any flaking or peeling paint, it must be removed by sanding or scraping, so the paint will adhere. Where necessary, these areas should be patched and sanded so the surface is smooth and uniform. Start with a medium grit sandpaper and work to progressively finer grits until a smooth, uniform surface is obtained.
* If there are any rusty nail heads, remove the rust by sanding, countersink the nail heads, prime with a rust-inhibitive primer and apply spackle.
* Check masonry surfaces; wherever there's a crack, undercut it, wet it and apply a latex masonry caulk, or use a masonry patching compound. If necessary, use a wire brush to remove dirt, loose/peeling paint and loose masonry.
* After all the patching and sanding has been done, use a tack cloth, brush or broom to remove any dust from the surfaces to be painted.
* Next, use masking tape and paper or plastic to mask any items or surfaces that aren't going to be painted, like doorknobs, light fixtures, window panes, etc. The tape should be pressed firmly in place so the paint can't seep underneath.




When is priming necessary?

Some surfaces must be primed before painting, to ensure the best possible results. Primers are normally used for one or more of the following reasons:

* To fill and seal the pores in surfaces like bare wood or weathered masonry.
* To provide a smooth, even surface for the finish coat, especially for enamel topcoats.
* To cover the substrate, so the topcoat will hide better.
* To lock in stains from staining woods like cedar and redwood, and cover stains from water damage, knots and sap streaks.
* To bond to slick, shiny and other hard-to-paint surfaces, and create a surface the topcoat can adhere to.
* To provide corrosion resistance for metal substrates like iron, steel, aluminum and galvanized metal. In general, a primer should be used in the following situations:
o Primers should be applied over surfaces that have never been painted before, like new wood, masonry, and metal. On these surfaces, a prime coat will help create a uniform surface for the topcoat, for improved coverage, better adhesion, more uniform finish and easier touch-up.
o When repainting, primers are needed when a surface is weathered or when the surface has been stripped or worn down to the original substrate.
o Primers can also be used on hard-to-paint surfaces, where surface stains or poor paint adhesion may be a problem.

(Note: While primers are effective problem solvers, they can hide only so much. If a stain is caused by a leaky water pipe, for example, it's important to fix the leak before using a primer to conceal the stain. It's still important to properly prepare the surface, even if a primer is being used. This includes cleaning, patching, sanding, etc
















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