Blistering

Bubbles resulting from localized loss of adhesion and lifting of the paint film from the underlying surface.

Possible causes:

• Painting a warm surface in direct sunlight.
• Application of oil-based or alkyd paint over a damp or wet surface.
• Moisture escaping through the exterior walls (less likely with latex paint than with oil- based or alkyd paint).
• Exposure of latex paint film to dew, high humidity or rain shortly after paint has dried, especially if there was inadequate surface preparation.

Solution:

• If blisters go down to the substrate, try to remove the source of moisture. Repair loose caulking; consider installing an exhaust fan.
• If blisters do not go all the way down to the substrate, remove them by scraping, then sanding; prime any bare wood and repaint with a quality exterior paint.