Paint Blisters on Bricks

Excess Moisture

• Brick is a very porous material. Blistering paint is most often a result of excessive moisture coming through the brick. As the moisture evaporates, it prevents the paint from sticking to the brick and as the paint dries, the moisture actually lifts the paint from the surface.

Dirt and Contaminants

• Bricks that are coated with dirt, oils or other contaminants will have paint adhesion problems. Additionally, a white powdery residue called efflorescence can form on bricks due to moisture evaporation. Scrub all mold, dirt and foreign substances from bricks prior to priming and painting.

Oil vs. Latex Paint

• If the bricks were previously painted with an oil-based paint, painting over them with latex may result in adhesion problems. Oil-based paint cures by continuous oxidization which interferes with latex paint's ability to bond with the surface. Oil-based paint can be applied over latex, but latex cannot be applied directly over oil-based paint without the use of a primer.

Fixing Blistered Paint

• Scrape off all the blistered paint with a wire brush or scraper. Sand the area smooth with medium-grit sandpaper. Examine the area closely for loose mortar or cracks. If any flaws are found, fill in the mortar and use an elastomeric caulk to fill in gaps and cracks in the brick. Prime with an acrylic primer for masonry or high-quality, all-purpose primer. Work the primer into all the crevices to protect against moisture leaks and then paint using a brush or roller with a thick nap.