EXTERIOR
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Problem
| Possible Cause
| Solution
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Alligatoring - patterned cracking resembling the scales of an alligator.
| - Application of a top coat before the undercoat is dry
- Natural aging of oil-based (alkyd) paints due to temperature fluctuation.
- Application of a hard coating (enamel) over a softer flexible coating
| - remove paint by scraping and sanding the surface.
- prime the surface with a high-quality primer
- paint with a top-quality exterior latex paint
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Blistering - bubbles caused by loss of adhesion and lifting of the paint film from the underlying surface.
| - painting in direct sunlight on a surface that is too warm
- application of paint over a damp or wet surface
- moisture seeping into the walls (interior or exterior)
- insufficient surface preparation
| - If the blisters go down to the substrate then moisture is the problem. You will need to remove the source of moisture by either installing vents, exhaust fans, etc. Once moisture is dealt with sand, scrape and prime any exposed wood, then cover with a top quality exterior paint.
- If blisters go down the previous coat, remove all loose paint, sand the surface and smooth out any edges. Allow sufficient drying time before reapplying paint.
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Cracking or Flaking - the splitting of dry paint film through at least one coat. In early stages it appears as hairline cracks, in later stages flaking occurs.
| - use of low-quality paint
- spreading paint too thin
- poor surface preparation
- painting under cool or windy conditions which causes the paint to dry too fast
| - If cracking doesn't go down to the substrate remove the loose paint, sand to feather the edges, prime bare spots and repaint.
- For cracking that goes down to the substrate, remove all paint. Prime the wood or plaster before repainting. Apply high-quality exterior paint at the recommended spreading rate and recommended thinning rate.
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Efflorescence (white crystal deposits) - the formation of crusty white salt deposits, which are leaches to the surface of masonry or mortar as water passes through it.
| - inadequate surface preparation
- excess moisture escaping through the walls
- insufficient curing time for new cement or mortar
| - if moisture is the cause you will first need to eliminate the source. This could be repairing roofs or gutters, sealing any cracks in the masonry or installing vents or fans.
- remove all efflorescence from the masonry and rinse the surface. Apply a sealer, allowing it to dry completely, then apply a coat of high-quality paint.
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Mildew - black, brown or green blotches that form on the surface or caulk
| - damp or high-humidity areas that receive little sunlight/ ventilation
- painting over a substrate containing mildew
| - remove by scrubbing surface with a 1:3 solution of household bleach to water. Allow surface to dry thoroughly. re-painting may not be necessary. If you do need to repaint, use a top-quality acrylic latex paint as it resists mildew better than oil-based or alkyd paints.
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Rusting - reddish brown stains on paint surface
| - use of non-galvanised nails
- galvanised nails have begun to rust after excessive sanding or weathering
| - countersink the nail heads, then caulk with a top quality caulk.
- coat with a rust-preventative primer then topcoat.
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Paint incompatibility - loss of paint adhesion
| - use of latex based paints over alkyd or oil-based paints
| - remove the existing paint. Prime and repaint using the right paint.
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Peeling - loss of adhesion of a coating to the substrate
| - excess moisture
- inadequate surface preparation
- painting over a dirty, wet or glossy surface
| - Find and repair any source of water
- Remove all loose paint, sand rough surfaces and prime any bare wood. Repaint with a top quality paint.
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Wrinkling - crinkled paint surface forming a skin
| - paint applied too heavily
- exposure of uncured paint to rain, dew, fog or high humidity
- applying topcoat to undried first coat
- painting over an unclean surface
| - remove wrinkled coating by scraping and sanding.
- Make sure first coat is dry before applying the top coat. Allow extra time if you are painting in hot, cool or damp weather.
- Follow manufacturers recommendations for spreading rate and environmental conditions.
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INTERIOR
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Burnishing - an area that shows an unwanted increase in sheen or gloss of the paint film
| - frequent washing and spot cleaning
- use of a flat paint in an area where a higher sheen level would be better
- use of low-quality paint with poor stain and scrub resistance
- objects rubbing against the walls
| - choose a semi-gloss or gloss finish rather than a flat sheen in high traffic areas.
- wait at least two weeks before washing dry paint film to assure maximum washability and durability
- clean surfaces with a soft cloth or sponge and non-abrasive cleaners
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Cracking or Flaking - the splitting of dry paint film through at least one coat. In early stages it appears as hairline cracks, in later stages flaking occurs.
| - use of low-quality paint
- spreading paint too thin
- poor surface preparation
- painting under cool conditions which causes the paint to dry too fast
| - If cracking doesn't go down to the substrate remove the loose paint, sand to feather the edges, prime bare spots and repaint.
- For cracking that goes down to the substrate, remove all paint. Prime the wood or plaster before repainting. Apply high-quality exterior paint at the recommended spreading rate and recommended thinning rate.
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Foaming or Cratering - formation of bubbles and resulting in small, round concave depressions.
| - excessive brushing or rollering
- applying a gloss or semi-gloss over a porous or unsealed surface
- shaking a partially filled can of paint
- use of a roller with the wrong nap length
| - all paints foam to some degree during application. Higher quality paints are formulated so that the bubbles break while the paint is still wet.
- sand problem areas before repainting.
- gloss paints should be applied with a short-nap roller
- apply a sealer or primer over pours or unsealed surfaces before the top coat
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| Mildew - black, brown or green blotches that form on the surface or caulk | - damp or high-humidity areas that receive little sunlight/ ventilation
- painting over a substrate containing mildew
| - remove by scrubbing surface with a 1:3 solution of household bleach to water. Allow surface to dry thoroughly. re-painting may not be necessary. If you do need to repaint, use a top-quality acrylic latex paint as it resists mildew better than oil-based or alkyd paints.
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Picture framing - non-uniform colour when a wall is painted with a roller but is brushed at the corners.
| - applying paint at different film builds
- not keeping a wet edge while painting
- incomplete mixing of the paint
| - make sure spread rates of rollers and brushes are similar and apply the coating as uniformly as possible
- don't cut in whole room before rollering. Work in small sections to maintain a wet edge.
- all colours should be thoroughly shaken before use.
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Poor hiding (Transparent) - failure of paint to fully conceal the underlying colour or surface.
| - applying too thin of a paint
- use of the wrong type of roller or brush
- painting over a porous surface
- use of a paint that is much lighter or darker than the previous coat
| - prime the surface with an appropriate primer before topcoating, especially if the substrate is new, darker or is a patterned wallpaper.
- allow proper drying time before recoating
- follow the manufacturers directions for spread rate.
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Poor stain or scrub resistance
| - applying paint to an unprimed substrate
- use of low-quality paints
- choosing wrong sheen or gloss
- inadequate drying time
| - prime new surfaces for maximum film thickness
- choose high-gloss or semi gloss paints for high traffic areas
- wash with least abrasive material
- allow adequate drying time. Scrub and stain resistance doesn't fully develop until the paint is thoroughly cured.
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Roller marks or stippling - textured pattern left in the paint by the roller
| - use of incorrect roller
- use of incorrect rolling technique
| - do not let paint build up at roller ends
- sand problem areas before repainting or applying additional coats
- follow the recommended roller cover and nap size.
- only use high quality rollers as these will ensure adequate thickness and uniformity
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| Wrinkling - crinkled paint surface forming a skin | - paint applied too heavily
- exposure of uncured paint to rain, dew, fog or high humidity
- applying topcoat to undried first coat
- painting over an unclean surface
| - remove wrinkled coating by scraping and sanding.
- Make sure first coat is dry before applying the top coat. Allow extra time if you are painting in hot, cool or damp weather.
- Follow manufacturers recommendations for spreading rate and environmental conditions.
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