Paint blisters or bubbles occur when the paint film lifts from the underlying surface. The loss of adhesion between the paint film and surface is usually caused by heat, moisture or a combination of both.
Thicker paint, or a slower brush action should reduce the problem. A bigger brush (with a good tip) will help, as it carries more paint so you can 'flow' it on more rather than scrub the brush back and forth so much.
It's probably caused by putting it on too thick and the environment was drying it too quickly. The paint can look like foam but that is hard to transfer as you brush and roll unless you are putting it on thick. Bubbles form because the solvent is trapped under the surface that dries first.
“Paint bubbles are a common issue and are largely due to the condition of the underlying surface when the paint was applied,” says Mike Mundwiller, field implementation manager at Benjamin Moore. “It can be corrected, but the root of the problem must be addressed or it will reoccur down the line.”
Generally, these bubbles pop quickly, leaving the paint to dry smooth. If you notice the bubbles popping soon after application, they usually go away on their own without leaving craters. If not, adjust your paint, roller or technique to minimize bubbling.
If the blisters do not go all the way down to the substrate, remove them by scraping and sanding. Once the problem area has a smooth finish, coat with primer before applying a quality acrylic latex interior paint. If the blisters go down to the substrate, you will need to remove the source of moisture, if possible.
There are two main causes of it: heat and moisture. Painted walls too close to a stove or improperly insulated fireplace may bubble as the paint pulls away from the wall. However, it's a much more common sign of water damage.
Excessive Heat and Sun Exposure
Extreme heat and prolonged sun exposure can cause the expansion and contraction of surfaces, leading to bubbling paint. Additionally, direct sunlight can degrade the paint's protective properties, allowing moisture to penetrate and cause bubbles.
POSSIBLE CAUSE
Applying a gloss or semi-gloss paint over a porous or unsealed surface. High heat during application speeds up drying; bubbles or craters that form will dry before they can break and level out. Using a thinner/reducer that is inappropriate for the coating.
A common cause of fresh paint bubbling on wall is failing to clean the surface first. Dirt and greasy marks (e.g. fingerprints) can form a barrier between the emulsion and the wall, preventing it from adhering. As the paint dries, it will pull away from any dirty patches, forming a visible bubble around them.
Many painters “break in” a roller cover by priming it with water or thinner. In our lab we never prewet a cover before painting. If you choose to, you must spin it out with five or six strong pumps so it is only lightly damp. Then take even more moisture out by blotting the cover with a paper towel.
All paints will foam to some degree during application; however, higher quality paints are formulated so the bubbles break while the paint is still wet, allowing for good flow and appearance. Avoid excessive rolling or brushing of the paint. Apply gloss and semi-gloss paints with a short nap roller.
POSSIBLE CAUSE
Excessive brushing or rolling – applying a paint too rapidly – will drive excess air into the film. Use of a roller cover with wrong nap length. Applying a gloss or semi-gloss paint over a porous or unsealed surface.
Glossy paint: 1-1 ½ hours and 2 hours before applying the second coat. Semi-gloss: It takes roughly 1 hour to dry and 2 hours before applying the second coat. Matte Paint: 30 minutes to an hour for drying and 1-2 hours before applying the second coat.
Paint blooms when moisture penetrates the paint surface creating a milky effect. Paint blooming on floors is when moisture or condensation forms on a floor that effects the paint. Paint blooming creates a milky appearance.
Remove blisters by scraping, sanding or pressure-washing down to underlying coats of paint or primer. Repaint the surface with a high-quality interior/exterior paint (make sure the surface temperature is below 90º F). Find the best paints suited for your project.
Dealing with minor paint bubbles
Apply a thin coat of smoothing paint to even out the surface. Apply a primer before coating with another layer of paint. If you are applying a glossy or satin paint, you will have to repaint the entire surface as any patched-up areas will be clearly visible.
Getting rid of the bubbles is very simple! We use a pointed object, such as a pin or the blade of a utility knife, and engrave the surface of the bubble. In this way the air will be free to go out.
One of the primary causes of paint bubbling is applying paint on a dirty or poorly prepared surface. When the painting surface is contaminated with dust, dirt, grease, or other substances, it hampers the paint's ability to adhere properly. As a result, bubbles or blisters may form as the paint dries.
Paint can begin to blister, peel or crack a couple of days to a number of years after applying a new coat of paint. It is generally common on plaster or ceilings, but wooden frames, trims, decks and bathrooms can be affected too.
Bubbling paint often indicates a water leak.
Improper Paint Preparation
Paint adheres best to clean, dry, and smooth surfaces. If there's any residue, dirt, or grime on the walls, or if the walls are not properly dried before painting, the paint might not adhere correctly, leading to bubbling.
The usual causes of “blistering” include:
Moisture in the substrate (e.g. if moisture level in timber is over 15%). Poor substrate preparation to eliminate unsound & aged paint films. Dark colour which absorb a lot of heat, applied over light colours will force the moisture/air vapour to the surface more quickly.
The signs of water damage include peeling, flaking, and bubbling paint as well as hairline and spiderweb cracks. Water rings that are brown in color are a common water damage indicator. Another sign of damage is the growth of mold. It often appears in corners where ceilings and walls meet.