Common Exterior Paint Problems

Blistering
Paint bubbles indicating loss of adhesion. Can occur in isolation or groups.

Probable Causes
Trapped moisture truing to escape through the paint, painting at temperatures above 90 degrees. Using oil paints on wet/damp surfaces. High humidity, such as rain or heavy dew before the paint dries. Painting a warm surface in direct sunlight, or application over heavy chalk.

Solutions
Find and remove the sources of moisture. Control moisture with adequate venting, stopping leaks and acrylic caulking. Remove all of the blistered areas and loose paint by appropriate methods. Power washing recommended for large areas. 

Under Eaves Peeling
Occurs in protected or shady areas where condensation collects sulfur dioxide from air. These salt like crystals are washed away by rain in areas not protected. Painting over these crystals will cause peeling as the salt draws moisture from the paint.

Probable Causes
Improper surface preparation to painted surfaces located in areas protected from weather. Condensation causing a collection of salt crystals from the air. If salt deposits are not removed, new paint will peel. Lack of adhesion of a top coat over a hard, shinny surface.

Solutions
Wash and rinse thoroughly before repainting. When dry, remove all loose paint with a scraper or wire brush. Sand all glossy areas and remove sanding dust. Remove mildew if present.

Efflorescence (see frosting)
Crusty, white salt deposits leached from masonry or mortar as moisture passes through.

Probable Causes
Excessive moisture, inadequate venting of interior moisture laden areas. The pH level is too high or the lack of curing time. Excessive lime in concrete mix. Soluble salts in masonry when dissolved by water appear on the surface as crystallized salts.

Solutions
Requires the elimination of moisture sources. Remove all loose paints and other particles with a wire or stiff brush before repainting. Fill all cracks with a masonry-patching compound. Repair any leaks or other moisture sources.

Primers & Exterior Finishes
Masonry primer/sealer is essential and mist dry completely before repainting. Select a top quality exterior paint in the color and sheen of your choice. 

Fading/Color Retention
Early loss of color or change usually from direct sun exposure. More pronounced with yellows and reds.

Probable Causes
Using an interior grade of lightly pigmented paint leading to rapid degradation. Using a color that isn't light fast. Tinting white paint not intended for tinting. Over tinting. All colors will fade somewhat over a long duration.

Solutions
Remove all loose paint and other particles with a wire brush before repainting. All chalking must be removed. Rinse thoroughly with a garden hose. For the best and quickest results, use a power washer. 

Galvanized Metal Peeling
An adhesion loss of the paint due to inadequate surface preparation.

Probable Causes
Usually no or improper priming. Improper surface preparation or choice of paint. Not removing rust, oil and other matter. Not deglossing baked enamel finishes. Painting too soon after cleaning galvanized surface. Galvanized metal is very alkaline until weathered.

Solutions
Remove all rust, loose paint and other particles. All dust must be rinsed or wiped away. Allow galvanized to weather prior to coating. Apply an acrylic corrosion-resistant primer. New galvanized must be primed with an acrylic corrosion-resistant primer if the finish coat is oil base or vinyl latex.

Primers & Exterior Finishes
Bare or new galvanized metal needs agressive cleaning with mineral spirits prior to using a galvanized primer. Select a top quality exterior paint in the color and sheen of your choice. 

Gloss Retention
An accelerated deterioration of the topcoat causing rapid luster loss.

Probable Causes
Usually the use of gloss or alkyd or oil based paint exposed directly through the sun. Thin or inadequate paint film. Paint colors such as oranges, reds and yellows that are particularly vulnerable to UV radiation. All paints lose some luster over time.

Solutions
Use top quality UV resistant exterior paints. Acrylic glosses last much longer than oil or alkyd based paints. Remove all loose paint, dust, or other particles. Rinse thoroughly with a hose. For best and quickest results, use a power washer.

Primers & Exterior Finishes
Spot prime all bare areas. Also refer to the section on Chalking. Select a top quality exterior gloss paint in the color of your choice. 

Lapping
Occurs where wet and dry layers overlap during painting. Avoid with paint area management and technique.

Probable Causes
Wet and dry layers overlapping. Too much heat or wind during application. Inadequate stirring or improper thinning. Extremely porous surface. Painting too large an area at one time, such as trying to go from the top to the bottom.

Solutions
Another coat of paint, evenly spread, will usually cover lap marks. If the finish coat is relatively transparent, or the surface is overly porous, a primer or a second coat may be necessary. Always paint from wet to dry and in small sections to keep a wet edge.

Primers & Exterior Finishes
Extremely porous painted or unpainted surfaces need a primer/sealer coat before a new topcoat. Select a top quality exterior paint in the color and sheen of your choice. 

Mildew
Areas of black, gray, brown spots formed on paint and other surfaces, particularly in damp, shady areas.

Probable Causes
Warm humid conditions, poor air circulation and little direct sunlight, like under eaves and overhangs. Shrubbery planted too close to a building is an ideal place for mildew to grow. Mildew must be removed before painting or it will come though the new paint.

Solutions
Remove all mildew by scrubbing with a solution of household bleach and water. Mix 1 part bleach to 3 parts water. Wear rubber gloves and eye protection. Power washing is recommended for larger areas. Rinse thoroughly with a garden hose.

Primers & Exterior Finishes
Priming is essential for better adhesion, sheen uniformity, mildew control and durability. Select a top quality exterior paint in the color and sheen of your choice containing mildewcidal protection.