Problems & Solutions Exteriors

Common Paint Problems & Solutions

We have the solution to resolve any Exterior Problem

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 top coat before the undercoat is dry.

Natural aging of oil-base 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 surfaces; 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 a high quality latex or oil-based primer, then painted with a top quality exterior latex paint.

Blistering

Blistering is the formation of bubbles resulting from localized loss of adhesion and lifting of the paint film from the underlying surface.

Possible Causes

painting in direct sunlight or on a surface that is too warm, especially when applying a dark-colored solvent-based coating.

applying an oil-based or alkyd paint over a damp or wet surface.

excess humidity or other moisture escaping from inside through the exterior walls (less likely with latex paints, which allow water vapor to escape with out affecting the paint film).

exposure of a latex paint film to excessive moisture in the form of dew, high humidity or rain shortly after the paint has dried, especially if there was inadequate surface preparation and/ or a lower quality paint was applied.

Solution

First, determine whether or not the blisters go all the way down to the substrate.

If they go down to the substrate, the problem may be due to moisture coming from inside. Take steps to remove the source of moisture, if possible. Repair loose caulk and consider installing vents or exhaust fans. If the building has wood siding, install siding vents in areas where blistering has occurred. Remove blisters by scraping and sanding, prime any areas where bare wood shows, and repaint.

If the blisters do not go all the way to the substrate, the problem is probably not related to moisture coming from behind. Rather, the blisters are likely from painting a warm surface in direct sunlight or exposing the paint film to excessive moisture. In any case, sand, scrape and then prime any exposed bare wood. Coat with a top quality acrylic latex exterior paint.

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 paint 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.

Efflorescence

Efflorescence is the formation of 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 walls from the inside

Solution

If excess moisture is the cause, eliminate the source by repairing the roof, cleaning gutters and downspouts and sealing any cracks in the masonry using a 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 all efflorescence and loose material from the masonry with a wire brush, power brush or power washer; then rinse. Apply a masonry sealer and allow it to dry completely; then apply a coat of top quality exterior house paint.

Mildew

Mildew is the formation of brown, black or gray spots or blotches on the surface of paint or caulk due to the presence of fungi that feed on the paint film and other organic matter.

Possible Causes

damp areas that receive little or no direct sunlight (such areas as walls with a northern exposure and the underside of eaves are particularly vulnerable).

use of a lower quality paint with an insufficient amount of mildewcide.

painting over a substrate or coating on which mildew is present.

failure to prime bare wood before painting.

Solution

First, make sure that the discoloration really is mildew, and not just dirt. Apply a few drops of household bleach to it, wait five minutes, then rinse. If the dark color disappears, the discoloration is probably mildew.
Remove all mildew by scrubbing with a diluted household bleach solution (one part bleach, three parts water). Be sure to take the proper safety precautions.wear rubber gloves and eye protection. Leave the bleach on the surface for several minutes, then rinse. Next, thoroughly clean the surface with a detergent solution to remove dirt and other organic material on which mildew can feed. This can be done by hand or with a power washer. Rinse again. When the surface is dry, apply one or two coats of top quality acrylic latex paint -- this type of paint contains extra mildewcide and will resist mildew better than oil-based or alkyd paints.

Nailhead Rusting

Reddish-brown stains on the paint surface.

Possible Causes

Non-galvanized iron nails have begun to rust, causing bleed-through to the top coat.

Non-galvanized iron nails have not been countersunk and filled over.

Galvanized nailheads have begun to rust after sanding or excessive weathering.

Solution

When painting new exterior construction where non-galvanized nails have been used, it is advisable to first countersink the nailheads, then caulk them with a top quality, water-based all-acrylic or siliconized acrylic caulk. Each nailhead area should be spot primed, then painted with a quality latex coating. WProblems & Solutions.htmhen repainting exteriors where nailhead rusting has occurred, wash off rust stains, sand the nailheads, then follow the same surface preparation procedures as for new construction.

Paint Imcompatibility

Loss of adhesion where many old coats of alkyd or oil-based paint receive a latex top coat. Problems & SolutionsExterior.htm

Possible Causes

Use of water-based latex paint over more than three or four coats of old alkyd or oil-based paint may cause the old paint to "lift off" the substrate.

Solution

Repaint using another coat of alkyd or oil-based paint. Or completely remove the existing paint and prepare the surface cleaning, sanding and spot-priming where necessary before repainting with a top quality latex exterior paint.

Peeling

Spontaneous loss of ribbons or sheets of paint due to loss of adhesion. When the surface is coated with a primer and topcoat, or with several coats of paint, the peeling may involve all the coats, some of them, or just the topcoat.

Possible Causes

swelling of wood due to seepage or penetration of rain, humidity and other forms of moisture into the home through uncaulked joints, deteriorated caulk, leaking roof or other areas.

excess humidity or other moisture escaping from within the home through the exterior walls (less likely with latex paints, which allow water vapor to escape without affecting the paint film).

inadequate surface preparation.

use of a lower quality paint that has inadequate adhesion and flexibility characteristics.

applying latex paint under conditions that hinder good film formation, e.g., on a very hot or cold day; in windy weather.

applying an oil-based paint over a damp or wet surface.

Solution

If exterior moisture is the cause, eliminate the source by doing necessary repairs and maintenance:

*replace caulking;
*repair roof;
*clean gutters and downspouts;
*cut heavy vegetation away from the building.

If moist air is originating from inside, consider installing vents (especially in rooms that tend to get humid such as the kitchen, bathroom and laundry room); attic louvers, exhaust fans and dehumidifiers may also help. Remove all loose paint with a scraper or wire brush, sand rough surfaces and prime any bare wood. Repaint with a top quality acrylic latex paint. It will provide excellent adhesion and allow water vapor to escape without harming the coating.

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

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.