What Are the Causes of Bubbling Paint on Walls?

Humidity and Dampness

• Moisture plays a large role in creating paint blistering. Moisture on the walls will be absorbed by the newly applied paint, which creates bubbles and blistering. The water can also be in the air. Excessive humidity will be absorbed by the paint and lead to blistering. The paint may even blister soon after it has dried if the humidity levels around the walls are too high.

Warm Walls

• Paint contains solvents that help you apply the color and evaporate shortly after. Water is the solvent in most latex paints, and mineral spirits are the solvents in oil-based paints. The paint will develop a film as it dries that prevents air from getting in or out. However, if the solvent evaporates too quickly, it will "lift" the film from the surface, which creates a paint bubble.

Incompatibility

• The new paint must stick properly to the wall, or the resulting incompatibility will create bubbles. Blistering will develop if the walls are dirty or coated with residues, which make a barrier between the new paint and the wall's surface. Different types of paints may not be painted over very well, so painting one type of paint over another may result in an unstable bond and eventually severe blistering.

Prevention

• Most blistering may be prevented by following the paint manufacturer's instructions. Many paints come with a guide on the packaging that indicates the ideal temperature and humidity ranges for painting and that will lead to the smallest occurrence of blistering. Keep the room cool; if it's too hot, open some windows. Make sure the walls are clean of all dirt, grime and residues before painting, and use a primer to help the new paint stick to older paint if you're repainting a wall.