Description

Patterned cracking in the paint film resembling the scales of an alligator.

Possible Causes

• Application of an extremely hard, rigid coating, like an oil enamel, over a more flexible coating, like a latex primer or topcoat.
• Application of a topcoat before the primer or basecoat is dry.
• Natural aging of oil-based paints due to temperature fluctuation. The constant expansion and contraction results in a loss of paint film elasticity.

Solution

Before removing or sanding old paint, check to determine whether it contains lead. Lead may be harmful. Do not remove or sand paint without contacting local health officials for information on lead paint testing and safety precautions. Old paint should be completely removed by scraping and sanding the surface. A heat gun can be used to speed work on large surfaces, but take extreme care to avoid igniting paint or substrate. Follow all manufacturer instructions before using a heat gun. The surface should be primed with a high quality latex or oil-based primer, then painted with a quality exterior latex paint.

Description

The splitting of a dry paint film through at least one coat as a result of aging, which ultimately will lead to complete failure of the paint. In its early stages, the problem appears as hairline cracks;in its later stages, flaking occurs.

Possible Causes

• Use of a paint that has lower adhesion and flexibility performance.
• Over thinning or overspreading the paint.
• Inadequate surface preparation, or applying the paint to bare wood without first applying a primer.
• Excessive hardening and embrittlement of oil paint as the paint ages.

Solution

Remove loose and flaking paint with a scraper or wire brush, sanding the surface and feathering the edges. If the flaking occurs in multiple layers of paint, use of a spackling compound may be necessary to make a uniform surface. Prime bare wood or plaster areas before repainting. Use of a top quality Sherwin-Williams primer and topcoat should prevent a reoccurrence of the problem.

Description

Has the appearance of severe mildew but will not react to the "bleach test" listed in the Mildew section. Whereas mildew generally has a spotty appearance, darkening and decaying wood generally has a more solid, consistent appearance.

Possible Causes

Darkening of wood is caused by ultraviolet radiation. This can take place on wood that has never been coated with a protective coating. It also can occur under clear varnishes and lightly pigmented stains. Different degrees of darkening can occur on different woods. If moisture penetrates into the wood, varnish coatings will peel due to wood decomposition under the coating. Woods that are exposed to weather are not protected against wood-destroying organisms. Eventually the wood ceases to be a coatable surface.

Solution

New woods must not be exposed to harmful sun rays for extended time periods. If heavily exposed for more that 10 days, the wood should be sanded to a fresh surface before priming. Paint and stain adhesion performance is enhanced when the new wood is painted or stained immediately after installation. Wood that has been allowed to darken (decompose) must be sanded to fresh wood. Wood that cannot be sanded to fresh wood must be replaced.

Coatings can be applied to treated woods after the moisture content has dropped to a paintable level usually 15% or below. Paints, semi-transparent and solid color stains can be used on vertical surfaces or horizontal surfaces.

Description

Black, gray, green or brown areas on the surface of paint or caulk.

Possible Causes

The appearance of mildew or algae depends on various conditions, which are:.

• Continuously high humidity or dampness. As the humidity increases, mildew growth becomes more rapid.
• High average temperature.
• Poor ventilation. Still air increases mildew growth.
• Composition of surface. Mildew will grow on any surface that provides a nutrient, even dirt.
• Mildew occurs more often on light colors of paint film. Colors that do not absorb the sun's heat provide a surface for mildew growth.
• Cement based products are more prone to support algae growth.

Solution

Provide drainage and/or ventilation to remove excess moisture. Wash mildewed areas with Sherwin-Williams ProClean Mildew Remover or a solution of one part household bleach and three parts water. This will destroy mildew and bleach stains caused by mildew growth. Apply solution by brush or a garden sprayer apparatus. Heavy mildew may require additional applications, and scrubbing may be required. Flush area with clean water to remove bleach solution. Allow to dry thoroughly.

Peeling Plaster

Description

Loss of adhesion from plaster which can occur in spots or larger areas.

Possible Causes

• 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 wallcovering glue size, which absorbs water, and holds it underneath the paint.

Solution

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.

Peeling Due to Moisture

Description

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.

Possible Causes

• 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.

Solution

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.

Peeling

Description

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.

Possible Causes

• 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.

Solution

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.

Window Sill Peeling

Description

Loss of adhesion of the paint film (usually down to the bare surface) around window frames and sills.

Possible Causes

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.

Solution

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.

Description

Reddish-brown stains on the paint surface.

Possible Causes

Steel nails that are in contact with moisture will rust. Depending on conditions, this rust can either be red or black. Nail heads exposed to air will always be red rust-colored. If the nail is extracted and the nail shank is red, then the wood is saturated with moisture. Damp wood that possesses a high amount of tannic acid may develop black discoloration if it comes in contact with steel. Nail heads that are a black color are usually under the coating surface and will ultimately cause adhesion failure of the topcoat. Once exposed, the nail head will develop red rust.

Solution

Locate and eliminate the source of moisture. Replace nails with galvanized or other non-rusting nails. Rusty nails that cannot be removed must be sanded to shiny metal, countersunk, coated with a rust- preventive primer and then caulked. Repair moisture damage by sanding weathered wood to a fresh surface.

Description

Stains in the paint surface caused by virtually anything that would bleed, leak, or stick onto the paint film.

Possible Causes

• Water stains are caused by leaks in roofs, gutters, plumbing or just about any source associated with water.
• Heavy tobacco smoking leaves yellow nicotine stains that bleed through the topcoat.
• Fire/smoke damage.
• Moisture contacting uncoated or non-galvanized metal causing rust to occur.

Solution

The source of the water and rust must be repaired. Excessively damaged wood, plaster or drywall may need to be replaced. Peeling paint must be removed if present. The stained area must be properly sealed with a primer designed to "hold out" water and rust stains.

Tobacco smoke stains should be cleaned from the walls using Sherwin-Williams ProClean cleaner. Both fire damage and tobacco smoke stains must be sealed before topcoating.

All stains must be primed with the appropriate Sherwin-Williams primer in order to prevent bleed-through.

Description

Brownish or tan discoloration on the paint surface due to migration of tannins from the substrate through the paint film. Typically occurs on "staining woods," such as redwood, cedar and mahogany, or over painted knots in certain other wood species. However, tannin staining can occur with any kind of wood.

Possible Causes

• All woods, but especially red-colored woods, contain a water soluble dye called tannin. Tannin is not soluble in most solvents. Application of latex topcoats directly to these red-colored woods may develop a red-colored stain on the finish coat. If the dry film is intact and discoloration occurs at a later date, then staining is being caused by water moisture within the board wall. This moisture will migrate and eventually carry staining substances from within the wood to the surface of the paint film.
• Some cedar woods contain colored dyes such as tannin which is water soluble, and other colored extracts which are soluble in mineral spirits. In these instances, a primer that has discolored should be spot tested with a second coat of primer or a latex topcoat to determine which will successfully block future discoloration.

Solution

If dry film is intact and discoloration is occurring at a later date, then internal moisture is the culprit. The moisture source must be located and corrected. Remove stains by washing with a solution of equal parts alcohol and water. Allow to dry thoroughly.

New red-colored woods must be sealed with an oil primer that will function as a barrier coat, preventing staining of the topcoat.

Note: Even with proper preparation and recommended products, tannin bleed can still occur (especially on new woods) with both latex and oil topcoats.