There’s nothing more frustrating than waking up to a freshly painted wall that’s started peeling. Fortunately it’s a fairly rare occurrence, but when it does happen, 99% of the time it boils down to the substrate (the base surface). So if you’re asking yourself why is my paint peeling, then read on as we debug the potential issues and how to tackle it.
What is paint failure?
Paint failure, or paint adhesion loss, is the reduction of bond strength between a coat of paint and the surface to which it’s applied. It’s natural to immediately think you have a problem with your particular tin of paint (or batch) if you start to see an issue on the surface, but there are a few questions you can ask yourself, as well as understanding the different types of failure in order to begin diagnosing the problem. The objective fundamentally being to get your wall back to being a stable surface so you can finish your decorating.
My paint is peeling or flaking
Does this look like your wall?
First thing to check is whether the paint is peeling back to the previous coat and colour, or back to plaster. If the paint is peeling back to plaster, then you either have an unstable ‘mist coat’, possible chalky contract matt, or exposure to PVA from the plastering process (usually in corners) which is creating a weak layer, a bit like the jam in a sandwich not locking it together. As the top coat has dried it’s contracted and the weak layer has failed pulling the paint away from the wall. We have a whole blog dedicated to issues with plaster, so check it out.
If the paint is just peeling back to the layer below then there is an adhesion issue which needs to be tackled. Was the surface prepared properly? Was it grubby and dirty? Were there wallpaper paste remnants? Were there any other cleaning contaminants? Have you had a moisture issue? Or are you potentially painting over a glossy or older oil-based paint which could react with water? All could result in peeling or flaking paint. Cleaning and prepping a surface properly first is key.
My paint is mud cracking or bubbling
Mud cracking can occur when paint is applied too thickly, over a porous surface, or there is a build up in corners with excess paint. It’s really important to follow the guidance on the product to ensure you allow the correct amount of drying time in the right conditions. Rushing your painting can cause problems! Also a lot of folk try to slam on as much as possible in coat one. You're better off painting two even coats as you'll get a better base, adhesion level and final finish.
Bubbling paint is a blister or pocket which has reacted and expanded. It can occur when painting is taking place in direct sunlight or the surface is too hot, if you’re applying on to a wet surface or old wallpaper paste, or if there is excessive moisture and humidity.
What about the paint itself?
Always drop your paint supplier a line if you have an issue, stating the product information, batch number and supporting pictures. This will allow them to check that other customers haven’t had the same issue and help you diagnose the problem. If you’re not confident to rectify a peeling issue then it’s always recommended that you seek the advice of a professional, reputable decorator, although a lot of the resolutions are fairly straightforward - they just take a bit of time. You can also test the paint you’ve used in an inconspicuous area on another clean wall just for peace of mind.
So how do I fix my flaking paint?
As we mentioned before, the aim of the game now is to create a stable surface again. You have two options, fix it, or lock it in!
To fix flaking, bubbling or cracking paint issues on the wall, the first step is to sand the walls down, scrape off any loose paint and fill imperfections, so the surface area is flat. A quick dust off will aid adhesion.
Then you can apply a full coat of Zinsser Peel Stop (or similar primer product). This will act as a barrier between any additional coats of product and the unsound surface underneath, as well as filling any minor cracks in the paint.
Remember the failure happened between the original surface and your first coat of new paint (potentially exacerbated if you’ve added a second). Take your time and let all coats dry and cure well. Once the Zinsser Peel Stop has sealed the problem areas and dried fully, you will be able to apply two coats of your chosen product on top.
Also be aware if you’re dealing with a moisture problem underneath, you may need specialist help to stop the cause, dry out and seal before moving forward.
For woodwork and trim, a similar story. Sand back the problem areas, prime if you’ve discovered the coating underneath is oil-based, then re-apply your top coat.
The other alternative is to lock it in, particularly if you have a dogs dinner of a surface anyway. Sand it as flat as possible, then line over the top of it, saving time on a full sand and scrape. Essentially it’s the same principle. All you’re doing is creating a sound surface on which to paint, but instead of using a barrier coat such as Zinsser Peel Stop, you’re sealing everything up and locking it behind lining paper.
So a quick sand over (nothing drastic), prime with a diluted paste, then hang lining paper. Ready mixed paste from the packet stuff if you’re just covering over a durable emulsion (non porous). Once it’s lined you can paint as normal.
COAT Paint Adhesion
COAT’s water-based paint is tested using the ISO 2049 cross hatch adhesion method (look it up, it’s like noughts and crosses). All our products perform to the highest standard when the surface is prepared according to our instructions. If you ever have any issues, just drop us a line.