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Peeling - Window Sills and Frames

Loss of adhesion of the paint film (usually exposing down to the bare surface) around window frames and sills.
  • Paint usually peels from window sills and frames because of moisture. Water standing on the sills eventually penetrates the paint film. When it later evaporates, the pressure from under the film causes peeling. This moisture may be condensation on the interior, or rain and snow on the exterior.
  • Paint also peels from window sills due to poorly sealed framing that was not properly caulked; or the caulk has cracked or peeled away, allowing water to undermine the coating.
Remove as much paint as possible by scraping or sanding, or using a chemical stripper, or heat gun. Follow all manufacturers' directions when using chemical strippers or heat guns. Test the coating in a 6" to 12" radius around any peeled areas to be sure the adhesion is adequate.

Prime bare surfaces with the appropriate primer and caulk where necessary, especially at angles and crevices, to eliminate any opportunity for moisture to penetrate into the substrate (e.g. the surface to be painted).

Do not seal or paint shut any vent holes in the window trim of storm windows.

If a wood surface is deteriorated, replace it using cedar, redwood, or pressure-treated wood. Prime the butt ends of the wood before installation to reduce moisture penetration.

The use of storm windows and dehumidifiers may help prevent recurrence of peeling.

For exteriors, use SWP® Gloss Oil Based Enamel or SuperPaint® Exterior Latex High Gloss Enamel for surfaces exposed to standing snow and rain to help keep water from entering the wood. On new wood, use an 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.