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

Possible Causes:

• Applying oil-based or alkyd paint over a damp or wet surface.

• Moisture seeping into the home through the exterior walls (less likely with latex paint).

• Exposure of latex paint film to high humidity or moisture shortly after paint has dried, especially if there was inadequate surface preparation.

Solution:

• If blisters do not go all the way down to the substrate: Remove blisters by scraping, and sanding, and repaint with a quality acrylic latex interior paint.

• If blisters go down to the substrate: Remove the source of moisture, if possible. Repair loose caulking; consider installing vents or exhaust fans. Remove blisters as above, remembering to prime before applying the top coat.