Blistering

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

Possible Cause:

• 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 high humidity, rain or dew shortly after paint has dried, especially if there was inadequate surface preparation.

• Painting a warm surface in direct sunlight.

Solution:

• If blisters do not go all the way down to the substrate, remove them by scraping, then sanding. Repaint with a quality exterior latex house paint.

• If blisters go down to the substrate, try to remove the source of moisture. Repair loose caulking and remove blisters as above. Apply a primer before applying the top coat.