Peeling (also known as cracking) is a very common paint problem. It occurs when the paint fails to adhere properly to the surface it is being applied to. There are many types of peeling problems associated with both interior and exterior environments. We have listed the most common paint peeling issues, their descriptions, possible causes and their solutions.
Loss of paint due to poor adhesion. Where there is a primer and topcoat, or multiple coats of paint, peeling may involve some or all coats.
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).
Painting over a dirty surface (wax, mildew, grease, chalk).
Inadequate surface preparation.
Use of lower quality paint.
Applying an oil-based paint over a wet surface.
Earlier blistering of paint.
Applying too thick of a topcoat.
Painting over a glossy surface.
Try to identify and eliminate cause of moisture. Prepare surface by removing all loose paint with scraper or wire brush, sand rough surfaces, prime bare wood and masonry/stucco. Repaint with a top quality latex exterior paint for best adhesion and water resistance.
Peeling Due to Moisture
Loss of adhesion of the paint film caused by high levels of moisture which penetrate the film and eventually push the film away from the substrate.
Excessive moisture in a home caused by cooking, showering or any other means which would place moisture in the air such as use of a humidifier, vaporizer or hot tub.
Excessive moisture in a home due to a high level of humidity in the basement and/or foundation.
Proper ventilation can fix most interior moisture problems. High moisture areas such as bathrooms with showers should have exhaust fans installed.
Proper ventilation in the walls and/or roof of the home may be necessary. Heavily insulated homes need a means for moisture to escape such as roof vents and possibly outside wall vents.
Allowing moisture to escape via open windows can also be an option.
If high levels of moisture/humidity exist in a basement, the cause of this must be determined and fixed.
Once proper ventilation has been installed, peeling paint should be removed and the underlying surface cleaned and primed.
Window Sill Peeling
Loss of adhesion of the paint film (usually down to the bare surface) around window frames and sills.
Paint usually peels from window sills and frames because of con-densation. Water standing on the sills eventually penetrates the paint film. When it later evaporates, the pressure from under the film causes peeling.
Paint also peels from window sills due to poorly sealed framing that was not properly caulked or the caulk has cracked or peeled away.
Remove all the paint by scraping and, if necessary, using a chemical stripper. The use of a heat gun is a good alternative to chemical strippers. Either method can damage unprotected glass or window sealing materials. Follow all manufacturer directions when using these products. Caulk where necessary especially at every 90 degree angle and crevice to eliminate any opportunity
for moisture to penetrate into the wood substrate. Coat the sill with an exterior primer and finish coat. When painting frames, leave a small 1/16 inch edge of paint on the pane to prevent water from getting behind the film. Open vent holes in aluminum window trim.
Other solutions involve using cedar wood as a replacement for pine, which soaks up water like a sponge. Paint the butt ends of the wood before replacing the sills.
Use oil-based gloss paint or SuperPaint High Gloss for surfaces exposed to standing snow and rain to help keep water from entering the wood. On new wood, use oil based primer and two topcoats of exterior gloss. Both SWP
oil gloss and SuperPaint High Gloss stand up particularly well to higher moisture levels.
The use of storm windows and dehumidifiers helps prevent recurrence of peeling.
Peeling From Plaster
Loss of adhesion from plaster which can occur in spots or larger areas.
Peeling from plaster could be a result of insufficient wet troweling of the white coat when the plaster was originally applied, causing chalking of the surface.
Another possible reason for peeling is the use of a wall covering glue size, which absorbs water, and holds it underneath the paint.
Plaster should be clean and free of any sizing that would reduce adhesion. Test for this by wetting the surface and feeling for and greasy/slick substance. If present, this must be washed off before priming.
All new plaster should be primed after it has been cured a minimum of 30 days. This will reduce moisture and alkali. After curing and before priming, wipe the plaster with a damp cloth to remove powder and dust.
If peeling has already occurred, remove as much of the present paint and primer as possible by sanding or scraping before repainting. If just the peeling areas are removed, all the original primer may peel eventually, and the new coat will come off with it.
If the surface is badly disintegrated, cover it with canvas, mesh, hardboard or wallpaper liner, then plaster and paint the new covering.
Cracks and holes in plaster should be repaired before repainting. If patching is necessary, a water-mix patch or premixed plaster should be used when the intended topcoat is latex since oils in some patching compounds sometimes bleed into latex. When using a water-mix patch, thoroughly dampen the surrounding edges of the damaged areas of the damaged areas to prevent
the plaster from absorbing moisture and becoming crumbly.
Make sure the newly repaired plaster is similar in surface texture to the adjacent plaster so that the repaired area blends in with the original area.
Reprime and repaint the surface. On very chalky plaster, and oil-base primer such as PrepRite Wall and Wood is recommended because the oil wets the chalk and adheres better than water-base primers. Otherwise, PrepRite Classic Latex is an excellent solution.
Soft, porous or powdery plaster should be treated with a solution of one pint of vinegar to one gallon of water until the surface feels hard. Rinse with water and allow it to dry before priming.
As you can see, there are may types of peeling problems but there’s a solution for all of them. As long as you understand what is causing it you’ll be able to apply the best solution to the problem.