Without a picture as mentioned it’s hard to say, but would try some of that tar spot remover you can get in car shops to see if it is sap or something that has just got on the car. Also check for coverage pattern, as in is it on the vertical sides or just the top and are there any areas not effected which would indicate the direction its come from. Also has anyone near you had any painting or industrial cleaning done on their houses as it could be something that got on that way.
How to Fix Emulsion Paint Bubbling on Wall
There’s nothing more frustrating than when emulsion paint bubbles on the wall. Even if the paint job looked great at first, unsightly wall paint bubbles can sometimes appear hours, days or weeks later.
But why does emulsion paint bubble? Usually, emulsion paint bubbling (also called blistering) occurs due to poor adhesion between the wall and the base coat of paint. There are many potential reasons for this, such as failing to prepare the surface before painting.
In this guide, we’ll discuss the most common causes of paint bubbling on wall, and how to prevent it. We’ll also share our top tips on how to repair bubbles in emulsion paint.
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What Causes Emulsion Paint to Bubble or Blister?
When a coat of emulsion starts to bubble or blister, it normally indicates an adhesion problem. This means that the paint has lost its bond with the wall, and has begun to pull away. Each bubble is a small pocket of air or water, trapped between the wall and the paintwork.
If the emulsion fails to stick to the surface in the first place, you’ll notice the wall bubbling when painting. However, if it gradually loses adhesion over time, the problem may not be obvious straight away. A wall may start to blister anywhere from a few hours to several months after painting.
As with most painting problems, prevention is better than cure. Knowing what caused your paint job to bubble will help you ensure it doesn’t happen again. Here are the most common causes of emulsion paint bubbling on walls.
You Overmixed the Paint
It’s important to stir emulsion before painting, especially if it has been sitting in the tin for some time. Stirring will help to redistribute the pigments and ensure an even finish.
However, if you stir too quickly or vigorously, you may introduce too much air into the paint. This can cause bubbles to form. If you notice lots of tiny wall bubbles when painting, overmixing may be the culprit.
To avoid this problem, stir the paint gently and slowly, for a few minutes at most.
The Wall Was Dirty
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.
To prevent this, scrub the wall thoroughly with wall cleaner and a sponge. Allow it to air-dry fully before painting.
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The Room Was Too Hot
If you painted your walls on a warm day, it’s possible that high temperatures caused the paint to bubble. Extreme heat can cause emulsion paint to evaporate unevenly, with the top layer of paint drying out too quickly. When this happens, any moisture or air underneath the paint film can expand, causing blistering.
Try to avoid painting walls on hot days, especially in direct sunlight. Ideally, the room should be between 10°C and 35°C.
Moisture Is Trapped Beneath the Paint
When moisture becomes trapped beneath the paintwork, it can lead to emulsion paint bubbling on walls. This may occur immediately, if the wall was wet when it was painted. However, water bubbles can also develop long after decorating. There may be many reasons for this, such as:
- Condensation
- Rising damp
- A plumbing leak
- Water ingress from outside the property (penetrating damp)
Damp and water ingress should be professionally addressed before repainting. If the problem is humidity (e.g. in bathrooms and kitchens), use a breathable emulsion such as Earthborn Claypaint. This will allow moisture to flow through the surface of the paintwork, preventing blistering.
Please see our range of Earthborn Paints:
You Didn’t Use a Primer
If the wall is in good condition, it’s not always necessary to use a primer. But in some cases, such as when painting bare plaster, emulsion may have trouble adhering. This can result in the fresh paint bubbling on wall as it lifts away from the surface.
Primer can help prevent blistering by helping the paint to form a strong bond with the wall. For emulsion, choose a quality water-based primer such as Auro 505 Grip Coat or Auro 301 Plaster Primer. Alternatively, you can use emulsion paint diluted with 10-20% water.
Ensure the priming coat is completely dry before painting. Applying paint over damp primer may lead to bubbles forming due to moisture.
How to Fix Paint Bubbles on Wall
To fix paintwork that has bubbled or blistered, you’ll first need to identify the root cause. If you break open a blister and there is moisture behind it, you may have a damp problem. This will need to be addressed before repainting (e.g. by having a damp proof course installed).
Once you’re ready to redecorate, follow these steps to repair bubbles in emulsion paint:
- Wearing a dust mask, gently scrape away any loose or flaking paint using a putty knife
- If there are any holes or dents in the wall beneath, apply filler to create a smooth surface
- Sand down the area you’ll be repainting using fine grit sandpaper
- Thoroughly clean and dry the wall, and apply a coat of primer if necessary
- Repaint the surface using a paint brush (or a paint roller for larger areas). Apply the emulsion thinly and wait for it to dry before adding a second coat
Avoid repainting in extreme temperatures or humid conditions (above 70% humidity). Open windows to encourage air flow as the paint dries.
#2 Tomm
Tomm
- Location: Rochester, Kent
Posted 03 November 2012 – 08:43 AM
Photos are going to be a great help with people giving you advice regards this. It’s always hard to describe a paint problem and far quicker/easier with a photo.
Hopefully it is something which can e corrected/detailed out.
#3 Jimmy Hat
Jimmy Hat
One Carb Or Two?
Posted 03 November 2012 – 09:28 AM
Not sure how well its going to show up in photos but I will give it a go, in the meantime it is just loads of really tiny bubbles all the way across the paint
#4 sonikk4
sonikk4
Twisted Paint Polisher.
- Name: Neil
- Location: Oxfordshire
Posted 03 November 2012 – 12:39 PM
It sounds like moisture under the paint or there has been a reaction to something.
