Blistering paint is identified by small to medium sized bubbles or blisters under the paint film and is most common on wood siding and trim.

• Painting in direct sunlight on a hot substrate (surface being painted) which traps solvent vapor as the paint dries too quickly.
• Painting when the wood is damp causing trapped moisture to expand the paint film.
• Dew, rain or very high humidity after latex paint has dried if the latex paint is of lower quality or the substrate surface preparation was inadequate.
• House moisture escaping through the walls due to improper house ventilation.

• Scrape away blistered paint and sand to bare wood.
• Let wood completely dry.
• Sand, prime and paint in non-direct sunlight and non-humid conditions.
• Use high quality latex paint.
• If due to lack of home ventilation, corrective repairs must be made to properly ventilate the home’s walls, roof and eaves, bathrooms, etc.
• Check and repair any loose or missing caulking around windows and doors.
• Consider providing siding ventilation.

“Alligatoring” is a failure in the paint film where it takes on a cracking pattern of deep relief resembling a reptile’s skin, such as that of an alligator. “Checking” is a similar failure but is less severe and is characterized by long, fairly evenly spaced cracks in the paint film having shallow relief or depth. Occasionally checking may become severe in some areas and a deeper crack or split in the paint will occur.

• A second coat of paint was applied over a first coat of primer or paint base coat before it dried.
• A second coat of paint was applied over an incompatible paint such as a glossy paint or a hard oil enamel over a latex based paint.
• Oil based paints naturally aging and losing the little elasticity the paint film originally had, therefore it cracks due to fluctuations in temperature.

• Natural aging of several layers of older oil based paint. As the material having been painted shrinks and expands over time (usually wood), the paint has to move and as it loses elasticity, it checks.

• The fix is the same for both problems.
• Remove the old paint, sand, prime and repaint with flexible latex based paint.
• Use high quality latex paint.

A problem of painted masonry construction, efflorescence is identifiable by crusty white salt deposits that bubble through the paint film from a masonry structure. Salts in the brick or concrete become dissolved with water and then leach to the surface as the water evaporates.

• Poor paint surface preparation where prior efflorescence was not entirely removed and washed before the surface was repainted.
• Heavy moisture migrating through exterior masonry walls from inside the home.
• Inadequately waterproofed basement walls allowing ground water penetration.
• Painting masonry construction before the concrete or mortar had adequately cured and dried out.
• Cracks in masonry wall or poor tuckpointing is allowing water to get behind masonry wall.

• If moisture is getting into the masonry wall eliminate source of moisture by properly tuckpointing any cracks or missing mortar in the wall or patching concrete with a latex concrete patch, clean out gutters and downspouts, caulk joints around windows and doors with a butyl rubber caulk.
• If moisture is migrating through the wall from the outside (e.g., basement wall), apply waterproofing to outside of wall.
• Remove all efflorescence and loose flaking, chalking paint with a wire brush, scraping or power washing before repainting.
• Clean area with a trisodium phosphate cleaning solution and rinse with clean water.
• Let completely dry and paint with a high quality latex house paint

Chalking is identifiable as a fine chalky powder that forms on the surface of a paint film. Although some chalking is a normal way paints self clean when exposed to the sun and rain, excessive chalking can be a paint failure. In dry arid climates where there is little rain, chalking can become excessive. Chalking is actually the paint pigment released by the paint binders which have been broken down by exposure to the weather. Chalking is especially typical of very light colored flat paints, especially lesser quality oil based paints containing high levels of pigment extenders. When chalking gets severe it may run off onto and stain surrounding construction as in the above photo.

• Use of cheaper quality exterior paint containing high levels of pigment extenders.
• Improper paint was used in an exterior application (such as an interior paint).
• Lower quality factory finished aluminum siding.
• Over-thinning paint.
• Not properly sealing a porous surface before painting.

• Chalking is considered dirt and must be removed before repainting.
• Remove chalking by power washing or scrubbing with a trisodium phosphate cleaning solution and rinse with clean water.
• Let dry and paint with a high quality latex house paint.
• To clean brick areas stained by chalking runoff the masonry should be scrubbed with a specialized masonry cleaning solution. If staining persists, a professional cleaning contractor may be required to clean the brick.

This paint failure is easily identified as a dripping or drooping look to areas of the paint film.

• Application of a coat of paint that was too heavy or overloaded
• Heavy handed paint application
• Paint thinned too much at time of application
• Paint was applied in poor environmental conditions such as too cool or when humidity was too high
• Paint was applied without primer to a high gloss vertical surface preventing the paint substrate from having the “tooth” necessary for the finish coat to adhere
• Painted surface was not clean or properly prepared at the time of application

• If you catch the paint while still wet, use a brush or roller to redistribute the excessive paint evenly
• If the paint is dried, sand the uneven area and lightly reapply paint
• If paint was applied to a glossy surface, sand the glossy surface to dull it and create a “tooth” for the paint to adhere or apply a primer and repaint
• Paint using two light coats instead of one very heavy coat
• Do not overload the paint brush

Mildew is a fungus feeding and growing on the paint film or caulk and is identifiable by its grey, brown, green or dark black “splotchy” spots.

• Combination of moisture, poor ventilation and lack of direct sunlight. Underside of soffits and eaves are especially prone to mildew
• Painting over a surface or prior paint film that still had mildew
• Use of lower quality paint having inadequate mildewcide
• Not priming bare wood before painting

• Wearing eye protection (goggles) and rubber gloves, scrub vigorously with a trisodium phosphate cleaning solution or a household bleach solution of 1 part bleach to 3 parts water
• Let the solution set on the cleaned are for 10-15 minutes
• Rinse with clean water
• Wash the area with a detergent solution and rinse again
• Let completely dry and paint with a high quality latex house paint

This problem is characterized by rust colored reddish-brown to black stains on the paint surface.

• Non-corrosion resistant nails were used instead of galvanized zinc plated or stainless steel nails
• Steel nails became in contact with the air
• Steel nails popping from surface
• Excessive weathering or sanding has worn away galvanized coating on nail heads
• Tannic acid from moist wood (e.g., oak) has reacted with steel nails creating a black stain

• If possible, replace steel nails with galvanized or stainless steel nails
• If rusted nails can’t be removed then remove rust by sanding nail heads to bare metal and countersink
• Prime with a stain blocking rust inhibiting primer
• Caulk, fill or patch depressed nail heads and sand smooth
• Paint with a high quality paint

Peeling paint is a very common paint problem but can be caused either by moisture or poor adhesion. Peeling due to poor adhesion is characterized by the paint peeling and separating from an earlier paint layer (intercoat peeling) or from the substrate leaving some paint behind. Sometimes portions of earlier paint layers are visible under the curling, peeling paint layer.

• Painting over an surface with poor paint surface preparation such as being dirty, wet or shiny
• Substrate had poor adhesion prior to being repainted
• Applying oil based paint over a wet surface
• Blistering paint allowed to progress in failure
• Lower quality paint was used

• Scrape away old peeling paint and feather sand affected areas
• Spot prime bare area
• Caulk as required with appropriate caulking product
• Repaint with a high quality acrylic latex house paint

As mentioned in the previous section, peeling paint is a very common paint problem that can be caused either by moisture or poor adhesion. Peeling due to moisture is recognizable by large peeling sections of paint exposing bare wood underneath. Unlike peeling due to adhesion problems where peeling may be spotty, with moisture related peeling larger areas peel away often around windows, doors and gutters.

• Moisture getting behind paint film from failing or missing caulk, leaks in roof or wall systems or being too close to the ground
• Faulty guttering or missing ventilation causing ice dams or water back up
• Painting when the surface being painted is wet from condensation or rain

• Ensure proper drainage of gutters and downspouts flowing away from home
• Eliminate cause or source of moisture by installing exhaust fans, soffit vents, siding vents, louvers, fans, and dehumidifiers
• Repair and replace missing or damaged caulk
• Scrape away old peeling paint and feather sand affected areas
• Spot prime bare area
• Caulk as required with appropriate caulking product
• Repaint with a high quality acrylic latex house paint

Peeling of interior paint due to moisture is characterized by cracking and gentle peeling away of the paint from the substrate as it loses adhesion due to the moisture. Moisture originating from behind the paint film or in front and forcing its way through the paint film can create this type of paint failure.

• High humidity areas such as bathrooms, kitchens, hot tubs, wet basement areas and the like can create humidity that penetrates the paint film from the front.
• Leaking flashing around a chimney or other exterior wall / roof intersection can allow water to seep into the house and wet the plaster from behind the paint film causing the paint to separate from the substrate.

• Ventilate high moisture areas such as bathrooms by providing an exhaust vent fan that removes humidity and discharges to the outside
• Ensure proper ventilation of the roof and walls and soffits
• Repair missing or damaged flashing at chimney or other wall / roof connections
• Scrape away old peeling paint and feather sand affected areas
• Spot prime bare area
• Paint with high quality acrylic latex paint