Troubleshooting: Peeling

DESCRIPTION

The cracking and eventual peeling of the surface of a plywood or composition wood substrate. Plywood cracks from its expansion and contraction with changes in moisture and temperature. Plywood is prone to cracking because of its original construction from thin sheets of wood.


POSSIBLE CAUSES
  • Delamination results when wet wood swells, causing wood fibers to loosen, crack and fall off, taking all coatings with it. Moisture can seep behind paint films, absorbing into the wood, due to poor construction, poor or no caulking, lack of venting or sealing of the wood.
  • Pinholes in the paint film can also allow moisture behind the paint film causing delamination.

SOLUTION

To prevent cracking of newly installed plywood, sand and prime with a latex primer. If cracking has already occurred and is severe, replace the wood, as it is not re-paintable. If the cracking is not extensive, sand the surface smooth and remove dust and dirt. When the plywood is thoroughly dry apply a latex primer to bare surfaces and repaint.

Remove all loose and peeling paint. Power washing may be necessary for larger areas. Find and eliminate the source of moisture. Clean the surface thoroughly with a bleach and water solution. Damaged or rough surfaces may need to be sanded to the fresh wood. Remove the dust and allow to dry thoroughly. Seal all bare wood with an oil/alkyd primer, followed by the desired topcoat.

DESCRIPTION

Loss of adhesion of exterior paint, usually exposing the bare surface.


POSSIBLE CAUSES

Peeling results when a wet surface swells, causing the paint film to loosen, crack, and fall off. Water may seep under the paint film in many ways, including:

  • Worn-out or absence of caulking in joints, corners, and openings, allowing moisture to enter.
  • Clogging of gutters by ice dams or debris, causing moisture to penetrate under roof shingles.
  • Interior moisture migrating through to the exterior walls.
  • Painted surfaces that are too close to bare ground.
  • Leaking roofs.
  • Painting a surface that is damp with rain, condensation, or dew.

SOLUTION

Remove loose or cracked caulking and repair with a quality product.

Clean and repair gutters so they properly channel water away from the house. Be sure roof is vented and insulated properly to prevent ice dams.

Install vents, louvers, fans, and dehumidifiers to reduce moisture, especially in the kitchen, bathroom, and laundry areas.

If wood siding is touching the ground, remove that portion of the wood. Siding should be installed not less than 6" above the ground.

Repair the roof as needed.

Test the coating in a 6" to 12" radius around any peeled areas to be sure the adhesion is adequate.

Follow label directions for proper surface preparation and environmental conditions.

Remove all loose paint and sand rough edges smooth. Sand to remove loose wood fibers if present. Make sure surface is clean, dull, and dry. Prime with appropriate primer and recoat with good quality paint.

DESCRIPTION

Loss of adhesion of the paint film caused by high levels of moisture that penetrate the film and eventually push the film away from the surface.


POSSIBLE CAUSES
  • Excessive moisture in the home resulting from cooking, showering, laundering or the use of a humidifier, vaporizer, or hot tub.
  • Excessive moisture in the home due to a high level of humidity in the basement or foundation.

SOLUTION

Proper ventilation can fix most interior moisture problems. Install exhaust fans in high-moisture areas such as kitchens or bathrooms with showers to carry moisture-laden air to the outdoors.

Proper ventilation in the walls and/or roof of the home may be necessary. Heavily insulated and sealed homes need a means for moisture to escape, such as roof vents or outside wall vents.

Allowing moisture to escape via open windows is an option.

If high levels of moisture/humidity exist in a basement, the cause of this must be determined and eliminated.

Once proper ventilation has been installed, peeling paint should be removed and the underlying surface cleaned and primed. Test the coating in a 6" to 12" radius around any peeled areas to be sure its adhesion is adequate. Follow label directions for proper surface preparation.

DESCRIPTION

Paint adhesion is lost and the loose paint starts coming off in single or multiple coats.


POSSIBLE CAUSES
  • Lack of preparation before painting. Grease, oil, wax and dirt tend to soak in and are difficult to remove from concrete.
  • Failure to acid etch a smooth concrete floor before painting.
  • Hardeners added to concrete will often prevent good adhesion because they prevent the paint or stain from penetrating into the surface.
  • Concrete contains alkali which may be drawn to the surface by water. When the water evaporates the alkali leave a crystallized substance called efflorescence, which pushes against the paint film and causes peeling. If there is no moisture barrier under the concrete, moisture can easily seep through.
  • Old concrete may crumble, taking the paint film along with it.
  • An alkyd or oil base floor finish applied to an uncured concrete floor. When alkyd resins come in contact with the alkaline concrete surface, they combine, react with one another, and form a soap film between them. This is called saponification and results in extremely poor adhesion and softness of the alkyd coating.

SOLUTION

First, remove all loose paint by scraping or using a chemical stripper. Power washing is recommended for large areas. To clean the floor, scrub with hot water and a strong detergent or degreaser. Avoid mild dishwashing detergents; they contain skin-softening ingredients that may leave a residue on the surface. Rinse thoroughly and allow the surface to dry for several days. Stubborn grease may continue to rise to the surface and may require additional cleaning.

Once the floor is clean and dry, acid etching is recommended using a 10% solution of muriatic acid and water. (ALWAYS MIX THE ACID INTO THE WATER, NOT THE WATER INTO THE ACID). There are also phosphoric and citric acids that are much milder and recommended for indoor use. Allow the solution to remain on the surface for 10 to 15 minutes until all bubbling ceases. Flush the surface with clean water and allow it to dry completely, 2-3 days. Follow with the desired paint.

When the floor is properly etched it should resemble the texture of 120-grit sandpaper. Etching neutralizes the surface and provides a better bond. It also halts saponification, efflorescence and balances the pH level of the surface.

DESCRIPTION

Paint adhesion is lost and the loose paint starts coming off in single or multiple coats.


POSSIBLE CAUSES
  • Poor surface preparation.
  • Painting over a surface containing wax.
  • Painting over an old smooth coating.
  • Painting over chalky surfaces.
  • Buildup of moisture within the wood.

SOLUTION

Proper surface preparation will help to prevent peeling of the topcoat. All loose paint must be removed by scraping and sanding. Sand glossy surfaces to dull. To remove a wax residue on the surface, use TSP or degreaser. Power washing is recommended for large areas. Allow to dry 48 hours and repaint.

Identify and eliminate causes of moisture. Thoroughly clean the surface as above and allow to dry 48 hours and repaint.

DESCRIPTION

Paint adhesion is lost and the loose paint starts coming off in single or multiple coats.


POSSIBLE CAUSES
  • The most common causes of latex paint peeling from hard or slick surfaces is lack of curing time after painting and poor surface preparation. Although most quality latex paints dry very quickly, the hardening or curing process takes much longer, ranging from 2 to 4 weeks. During the curing period, latex paints are very susceptible to damage by abrasion or scratching. Over a properly prepared surface, enough time for curing is all that is needed for a satisfactory job. On some surfaces, special preparation is necessary or failure of the topcoat can occur.

SOLUTION

Prior to painting, all surfaces must be clean and free of wax, grease or dirt. All glossy surfaces need to be dulled by sanding (there are other methods of dulling a glossy surface such as liquid sandpaper).

If the old surface is still hard and slick, an appropriate undercoat, as recommended by the manufacturer, should be applied. Oil based primers will bond better to slick surfaces.

An application that requires a quicker cure time works best if a quality alkyd enamel is used. It is still important to allow enough time for curing even with the best preparation and application.

DESCRIPTION

Paint adhesion is lost and the loose paint starts coming off in single or multiple coats.


POSSIBLE CAUSES
  • As a rule, paints do not adhere well to smooth metal surfaces. Peeling from metal may be the result of failing to remove rust, not painting immediately after cleaning, or failure to use a primer when needed.
  • Galvanized metals are not only smooth, but the metal is also coated with a thin layer of oil to prevent white rust. Painting over galvanized metal without removing the protective layer of oil causes very slow curing of the paint and results in wrinkling and peeling.

SOLUTION

If rust is present, use a wire brush and sandpaper to remove as much loose paint and rust as possible. If the rusting is severe and cannot all be removed apply a rust converting coating, working it into the cracks, then topcoat with a latex paint.

For galvanized metal, the protective layer of oil must be completely removed. Solvent wiping (mineral spirits, lacquer thinner, etc.) is recommended. Weathered galvanized metal develops a layer of "white rust" which must be removed by wire brushing and sanding. Thoroughly remove all dust, then wipe with solvent and topcoat with latex paint or a Direct-to-Metal primer/finish.

Single Coat Peeling

DESCRIPTION

Single coat peel is when only the topmost layer of paint peels from the surface. This can happen both in both interior and exterior applications.


POSSIBLE CAUSES
  • Lack of proper surface preparation.
  • Applying paint over chalky, dirty surfaces.
  • Applying paint over glossy or tightly sealed surfaces without enough "tooth" to permit good bonding.

SOLUTION

Prior to painting, all surfaces must be clean and free of wax, grease or dirt. All glossy surfaces need to be dulled by sanding (there are other methods of dulling a glossy surface such as liquid sandpaper).

If the old surface is still hard and slick, an appropriate undercoat, as recommended by the manufacturer, should be applied. Oil based primers will bond better to slick surfaces.

An application that requires a quicker cure time works best if a quality alkyd enamel is used. It is still important to allow enough time for curing even with the best preparation and application.

Multi-Coat Peeling

DESCRIPTION

Multiple layers of paint are peeling from a surface, not just the most recent coat.


POSSIBLE CAUSES
  • Exterior - Delamination or breakdown of the substrate (usually wood or plywood).
  • Moisture penetrating beneath the paint film. This can happen if there are no vents installed outside the home, inadequate attic and roof ventilation, a wet or damp foundation, an uncovered crawl space, or untrimmed shrubbery resting against the siding. Poorly vented kitchens, bathrooms and laundry rooms in the house can also cause a problem because unvented moisture can migrate through walls.
  • Older and more brittle coats of paint underneath cannot withstand the repeated expansion and contraction as temperature and humidity change.

SOLUTION

Install vents, ventilating holes and/or louvers as needed. Vent bathrooms, clothes dryer, and gas space heaters to exhaust moisture to the outside of the house. Waterproof interior basement walls to prevent transmission of moisture to siding from surrounding wet or damp ground. Waterproof exterior foundation below ground level with tar or asphalt coating; trim shrubbery to provide ventilation. Cover crawl space ground area with barrier of roofing material or heavy polyethylene plastic sheeting.

Remove all loose paint and sand rough edges smooth. Sand to remove loose wood fibers if present. Make sure surface is clean, dull, and dry. Prime with appropriate primer and recoat with good quality paint.