Why has my paint bubbled?

There’s nothing worse than carefully painting your walls only to find before long that the paint has bubbled or blistered. Here, we’ll look at some of the key reasons why your paint may have bubbled. Plus, we’ll show you how to fix it.

There’s nothing worse than carefully painting your walls only to find before long that the paint has bubbled or blistered. Here, we’ll look at some of the key reasons why your paint may have bubbled. Plus, we’ll show you how to fix it.

Why has my paint bubbled?

If your paint has bubbled, it’s usually a sign that it’s struggling to adhere to the walls. Either the paint failed to stick properly in the first place, or it lost its bond with the wall over time.

When the paint starts to come away from the wall, this can result in a small pocket of air or water becoming trapped between the wall and the paint – which is often described as looking like bubbles or blisters.

Here are a few of the common causes of bubbling paint.

Dirty surface

Paint has trouble adhering to surfaces that are covered in loose particles or grease marks (like fingerprints). So, if you don’t clean your wall before painting, you may well get bubbles forming over dirty patches.

Wet surface

Moisture will stop paint from adhering. Problems such as rising damp, condensation and plumbing leaks can all cause paint to peel and bubble – whether they are present when you apply the paint or they occur long after.

Heat

Extreme heat can lead to your emulsion paint evaporating at different rates. If you paint your walls on a very hot day – especially in direct sunlight – the top layer of your paint can dry too quickly. This may cause moisture or air beneath to expand and blister.

Paint overmixed

Emulsion paint needs to be stirred before it’s used. But if you stir it too vigorously, you can cause air bubbles to form, which may still be visible when the paint dries.

Inappropriate roller cover

It’s important to use a roller cover that’s suitable for the surface you’re painting. If you use the wrong roller cover, this can result in uneven paint coverage and paint bubbles forming down the line.

Oil-based and water-based paint

Oil and water-based paints won’t bind. If you used oil-based paint directly on top of latex paint (which is water-based), the newer coat won’t stick and bubbles will appear.

Lack of mist coat

If you’re painting directly onto new plaster, it’s vital to do a mist coat first (a coat of paint diluted with water). Without this, your paint will bubble, flake and peel as it will have trouble sticking to your walls.

How to fix paint that's bubbled

First things first, you’ll need to work out why your paint has bubbled. For instance, if it’s due to a damp problem, there’s no point in repainting as the same thing will just happen again. Instead, you’ll need to treat your damp internal walls before you do anything else.

Once you’ve eradicated the root cause of your bubbling paint, it’s time to redecorate. Here’s how to swap your blistering walls for a smooth, seamless finish.

1. Scrape away loose, bubbling paint with a putty knife

2. Fill any dents in your walls

3. Sand down the area you plan to repaint

4. Clean and dry the wall

5. Add a coat of primer if necessary

6. Apply a thin coat of your new paint

7. Wait for it to dry

8. Apply a second coat

Make sure to avoid repainting in extreme conditions – such as in temperatures above 35°C or above 70% humidity. That way, you’ll give your fresh coats of paint the best possible chance of bonding well to the wall and sticking around long into the future.

Alternatively, why not get the help of a professional? A painter decorator near you will be able to easily identify the cause of your bubbling paint, and redecorate in a way that you know will last for years to come.