Paint Problems: Blistering & Peeling on Newly Painted Walls

Temperature Blisters

• Painting an exterior wall with oil-based paint in extreme heat can result in bubbles just a few hours after painting. These temperature blisters can also form days later. They occur because, in hot temperatures, a skin forms too rapidly on the surface of the paint, and the thinner in the wet paint beneath that transforms into vapor can’t escape, which is typically a problem with alkyd paints only. But dark colors or thick coats of latex paints in high temperatures may also form blisters. To correct the problem, allow the paint to dry for several days, and then scrape off the blisters and sand the surface smooth. Repaint the problem spots.

Moisture Blisters

• Moisture blisters can occur in both interior and exterior walls. On the surface they resemble temperature blisters, but, when first formed, they contain moisture that enters the wood beneath from outside through joints or other open areas of siding. Typically, on exterior walls the blisters are concentrated around joints and exposed end pieces of wood. Plumbing leaks, flooding and high moisture content in the air from showers and cooking can also seep into interior walls and cause moisture blisters. They usually penetrate through several coats of paint and collapse when they dry out. Small blisters may be unnoticeable when this happens. Larger blisters may peel.

  In new paints moisture blisters occur more commonly in oil-based paints but may also occur in thick coatings of latex paints. Older coatings tend to be too solid to swell but will crack. Because the newer paint is still soft, the moisture collects beneath it and it bubbles. The only solution to these blisters is to eliminate the source of the moisture before refinishing the walls.

Peeling and Cracking

• Peeling and cracking commonly occurs when new paint separates from the old paint coating, which is often due to improper preparation of the surface before painting and is seen within the first year of repainting. Occasionally cracking can occur if you’ve primed the walls and painted over it later. Waiting longer than two weeks before painting over primer can interfere with the new paint’s adhesion.

  Eliminating peeling and cracks requires sanding and preparing the wall properly by cleaning and then priming the surface before painting. You can test a paint surface to determine if it is ready for paint by applying a thin coating to a small area and leaving it to dry for two days or more. Press tape or a bandage over it and pull it off quickly. If the tape comes off without paint, the surface is good; if it does not, the surface requires cleaning and primer.

Thick Coats Versus Thin Coats

• Painting in thick coats does not reduce the number of coats required or the amount of work. It can result in cross-grain cracking, which is more common in older homes where walls may have several coatings of old paint on them. The cracks typically occur in the direction that the paint was brushed onto the surface and peel away. The only solution to these cracks is to remove the old coatings of paint and reapply with thin coats.