What Causes Wall Paint to Bubble And Crack?

D.P. Taylor
Written by D.P. Taylor
Updated March 30, 2023
Cracked paint
Photo: htpix / Adobe Stock

The main causes of paint bubbles are heat, humidity, and unclean surfaces

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You’ve finally finished painting the interior of your house—and then you notice something. There seem to be bubbles underneath the surface of the paint. But what causes paint to bubble?

If you’ve noticed paint blisters after painting a room, you’re not alone. This is a common problem that you can often prevent if you follow a few steps before painting. Keep reading to learn how to repair and prevent new paint bubbles and cracks on your walls.

What Are Paint Bubbles and Blisters?

Paint bubbles versus paint cracks on a surface

Paint bubbles and blisters are signs that the paint film is separating from the surface—and an indication that repair might be necessary. Paint blisters can happen long after the paint job was completed, and are usually caused by heat or moisture.

It’s an unpleasant progression for any homeowner. It starts with bubbles, which eventually leads to cracking and peeling. Ultimately, it ends with you hanging a picture over the area so your neighbors won’t see it when you have them over for dinner.

What Causes Paint Bubbles?

Paint bubbles form when the painter doesn't properly prepare the surface for the paint.

In order to avoid paint blisters, the surface should be:

  • Clean and free from contaminants

  • Not too hot (e.g., room temperature or cooler)

  • Dry

Also, blisters can form when a painter applies an oil-based or alkyd paint over latex paint, or if the latex paint gets exposed to moisture after it is applied.

How Do Paint Cracks Occur?

Wondering how that glaring paint crack happened in the first place? There are several potential culprits, from incorrect paint application to room temperature changes. Paint cracks form for separate reasons:

  • The paint dried too quickly.

  • The paint is warped by humidity over time.

  • The painter didn't use primer before applying paint.

Cost to Repair Paint Bubbles and Cracks

Cracked paint on wall
Photo: Piman Khrutmuang / Adobe Stock

Paint bubbles and cracks are unsightly and many homeowners get frustrated seeing their beautiful walls cracked and deformed. But, fortunately, fixing them is fairly affordable: The typical cost to hire a pro to repair paint bubbles and cracks on a wall runs from $356 to $1,171

However, you can attempt to remove unfortunate paint blemishes yourself using a scrape-and-patch method, requiring patience and a putty knife. Keep in mind that a DIY fix is best for repairing small areas, whereas hiring a pro is your best bet for recovering entire walls.

How to Fix Bubbling Paint and Cracks

No matter what caused the unsightly bubbles and cracks in your wall paint, it’s time to move forward to finding a solution. Luckily, there’s a scrape-and-patch technique that can help you restore your wall to its former glory. Repairing problems with paint is often labor-intensive, but the steps are simple.

  1. Lay down drop cloths to cover your floor surface from palling paint chips.

  2. Use a scraper or wire brush to scrape the damaged paint off the wall. 

  3. Rinse and dry your scraper tool.

  4. Use it to fill in holes or cracks with a quick-setting joint compound.

  5. Sand the area thoroughly to create a smooth surface. 

  6. Apply primer to the area and wait for it to dry, which takes as long as four hours. 

  7. Repaint the area.

How to Prevent Paint Bubbles and Cracks

If you want to prevent paint bubbles before they happen, take the following steps.

Clean the Surface Thoroughly

Painting on a dirty surface is a sure way to get bubbles, so scrub that surface thoroughly before applying paint. Dirt and dust prevents the paint from adhering to the surface properly, and eventually it may start to separate, forming bubbles.

Don't Paint if It’s Hot and Humid

Heat and moisture are the enemies of paint. Tiny water droplets can form underneath the surface of the paint at the bottom layer or even between coats. If you are painting in a humid environment, consider bringing in ventilation or fans to keep the area as dry and cool as possible.

Let Paint Dry Completely

Before a freshly painted surface is exposed to moisture, heat, and other elements, you must allow it to dry completely first. Latex paints dry the quickest and may only need four hours, but you should wait a full 24 hours for oil-based paints.

If you do not allow the paint to set properly, the heat and humidity in the environment can still disrupt the process and cause bubbles and cracking. Protecting paint from these forces is key early on.

Use Primer

A stain-blocking primer applied to the surface will prevent paint bubbling by sealing any pores the paint may sink into. After you apply the primer, wait for it to dry completely before painting over it. Also, only use a primer that is the same type as your paint (i.e., oil-based primer with oil-based paint and latex-based primer with latex-based paint).

Don’t Shake or Stir Too Hard

If you shake paint cans or stir the paint too vigorously, you can introduce air bubbles into the paint that will remain after you spread a coat over the surface. This is particularly a problem with lower-grade paints. If you need to stir the paint, do it slowly and deliberately.

Consider Hiring a Professional

Yes, you won't shy away from any challenge. But sometimes, it's better to let the pros handle the repair, particularly if you’re not experienced in painting walls, ceilings, and trim. By hiring a painter, you won't have to scrub the area clean of the bubbling paint and tackle that paint job again.

It's easy to find professional interior painters in your area. Once you settle on one you can trust, you can sit back and stop worrying about your walls. Maybe you can finally tackle that new deck.

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