Common Painting Problems & Solutions

Cracking
CRACKING / FLAKING

POSSIBLE CAUSES:

  • Use of lower quality paint that has inadequate adhesion and flexibility, over thinning or overspreading the paint.
  • Inadequate surface preparation, or applying the paint to bare wood without first applying a primer.
    Excessive hardening of enamel/oil based 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, using 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.

2
MILDEW

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 enamel/oil based or oil-based paint, or lower quality acrylic 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 discolouring 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 acrylic paint, and clean when necessary with bleach/detergent solution. Consider installing an exhaust fan in high moisture areas.

3
MUD CRACKING

POSSIBLE CAUSES:

  • Paint applied too thickly, usually over a porous surface.
  • Paint 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 acrylic paint. Mud-cracked areas can also be repaired by sanding the surface smooth before repainting with a top quality acrylic paint. This type of paint is likely to prevent recurrence of mud cracking, because it is relatively more flexible than enamel/oil based paint, oil-based paint and ordinary acrylic 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 minimise the tendency to apply too thick a coat of paint.

4
SURFACTANT LEACHING

POSSIBLE CAUSES:

  • All acrylic 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.

5
YELLOWING

POSSIBLE CAUSES:

  • Oxidation of enamel/oil based 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 acrylic paints tend not to yellow, nor does non-yellowing varnish. Enamel/oil based paints, because of their curing mechanism, are likely to yellow, particularly in areas that are protected from sunlight.

6
BLISTERING

POSSIBLE CAUSES:

  • Applying enamel/oil based paint over a damp or wet surface.
  • Moisture seeping into the home through the exterior walls (less likely with acrylic paint).
  • Exposure of acrylic 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 acrylic 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.

7
WRINKLING

POSSIBLE CAUSES:

  • Paint applied too thickly (more likely when using enamel/oil based 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.

8
ALLIGATORING

POSSIBLE CAUSES:

  • Application of an extremely hard, rigid coating, like an enamel/oil based enamel, over a more flexible coating, like an acrylic primer.
  • Application of a top coat before the undercoat is dry.
    Natural ageing 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 acrylic or oil-based primer, then painted with a top quality exterior acrylic paint.

9
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 acrylic 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.

10
CRACKING / FLAKING

POSSIBLE CAUSES:

  • Use of a lower quality that has inadequate adhesion and flexibility.
  • Over thinning 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 acrylic 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 acrylic paint.

11
EFFLORESCENCE / MOTTLING

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. 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.

12
MILDEW

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 acrylic primer, then a top-of- the-line exterior acrylic paint in flat, satin, semi-gloss or gloss finish, depending on the desired appearance.

13
PEELING

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 source 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 acrylic exterior paint for best adhesion and water resistance

14
POOR GALVANIZED METAL ADHESION

POSSIBLE CAUSES:

  • Improper surface preparation, such as inadequate rust removal.
  • Failure to apply a primer before application of an oil-based or vinyl acrylic 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 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 metal primer should be applied to unpainted galvanized metal, followed by a top quality exterior acrylic paint.

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