Paint Problems

Listed below are examples of common paint problems and their characteristics with a full description and recommended solutions.  Courtesy of Sherwinn-Williams Company.

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Cause: Slight chalking of a weathered paint film is normal and desirable. Application of new paint over severe chalk will cause peeling problems.

Aluminum siding can develop an excessively thick chalk layer and will require power washing to insure complete chalk removal.

Solution: Remove chalk by washing siding with detergent and water. If some chalk remains after first washing, then wash again for complete removal. Rinse well with clear water. Allow to dry thoroughly.

Recommendations: Aluminum Siding (Flat or Smooth)
Two coats Exterior Latex House and Trim Paint (Flat or Satin only)

Aluminum Siding (Embossed)
Two coats Exterior Latex House and Trim Paint (Flat, Satin, or Gloss)

Caution: Gloss paint on smooth aluminum siding will magnify metal imperfections when viewed at low angles.

Cause: The most common surface to show this failure is plywood that has been stained with a semi-transparent or solid color alkyd stain. The reasons for plywood separation are the same as those discussed in "Plywood Cracking," as they relate to moisture content, method of plywood manufacture and induced wood stress. The main difference is that although the coating cracks, it does not peel and lead to flaking. Instead, the wood is open for moisture intrusion from outside weather conditions, leading to delamination and deterioration of the plywood.

The wood is highly textured, allowing water to remain on the total surface for extended time periods. These woods are designed for staining and since plywood cracking is inevitable, the life of the coating is shortened. Pigmented stains penetrate the porous wood surface, allowing very little of the stain to remain on the surface. Subsequently, as the wood cracks, the applied stain also cracks.

Solution: Using detergent and water, scrub siding to remove old oxidized paint film, dirt and other contaminants. Flush with clean water and allow to dry thoroughly. Fill large holes found in plywood grooves with colored caulk to prevent further water intrusion.

Recommendations: Two coats solid color Alkyd or Latex stain

OR

Two coats of WoodScapes Exterior Acrylic Solid Color Stain.

Cause: When paint is applied over a partially dried bead of caulk, the paint dries, first forming a film. As the caulk continues to dry, it separates from the underside of the paint film. Ultimately, the paint film cracks.

Conditions that affect the drying time for caulks are air, surface or caulk temperatures below 40 degrees F; high humidity; and joints in excess of 1/2" in width or depth.

Solution: Surfaces to be sealed should be sound, dry, and free of oils, dust, mortar spatter, release agents, old caulk, bitumen, old paint or other contaminants. Remove flaky, loose and powdery material from the joint.

Apply caulk only when temperature of surrounding air, surfaces to be caulked and caulk are all above 40 degrees F. Do not apply when rain or freezing temperatures are expected.

Joints should not be more than 1/2" in width or depth. Joints deeper than 1/2" should be filled within 1/2" of the surface with polyethylene rod or closed cell urethane foam. Fill the remaining joint with caulk, and tool within five minutes of application.

Recommendations: One coat A-100 Latex or Alkyd Exterior Wood Primer

Two coats Exterior Latex House and Trim Paint

Cause: 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. 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. Semi-transparent stains must be used on all horizontal (walk-on) surfaces. Paints, semi-transparent and solid color stains can be used on vertical surfaces.

Caution: Wear a face mask to prevent inhalation of dust particles and mildew spores during sanding procedure. Keep mildew contaminated hands away from body openings, such as eyes, mouth and ears. Wash hands thoroughly as soon as possible.

Recommendations: Two coats WoodScapes Exterior Acrylic Solid Color Stain

OR

One coat A-100 Alkyd Exterior Wood Primer

Two coats Exterior Latex House and Trim Paint (Flat, Satin, and Gloss)

Decks and Porches (Walk-on areas)

Cuprinol Deck Care Products

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