I used Dulux™ undercoat and primer today for the first time. I cut in a small area and as soon as I started rolling, it was removing the paint! I had committed so I carried on. I let it dry and did a second coat, which was better. My questions are:

  1. Why did the paint peel off? I never have this problem with any other paint. (Walls were filled, sanded and washed prior to applying primer)
  2. Also if I very lightly sand will it make the job good again and will the sanding take away any effectiveness of the primer?

I am reluctant to use primer again and I have another room to do. Is a mist coat as effective as a primer paint. My goal is for the touch up jobs not to come through and to cover a darker wall with a lighter paint.

  • Paint should not peel off, unless previously paint job was done badly. Did paint peel from around the room or just certain spots? If much paint was removed, probably looking at a redo after heavy sanding.
    – crip659
    Mar 31, 2021 at 22:03

3 Answers 3


When your roller lifts the existing coat of paint from the wall surface it indicates that the wall was not prepared correctly or possibly something is affecting the bond to the wall (like moisture or heat).

Although the newly primed paint isn't pealing off the wall it would be wise to check that it has a good bond. Use a putty knife to try and scrape the paint from the wall. It should not come away if it has a good bond to the wall.

If it does scrape away continue scraping until it doesn't. Verify the primer has dried securely to the wall.

Sanding the walls wont help if the problem is with the original paint not being applied to a clean surface. The problem is contaminants preventing a proper hold from the paint.

Dulux is a very good paint brand. Check the label for any "warnings" the manufacturer may have.


The paint peeling off wasn't caused by the primer.

There's no such thing as "committed", if there's a problem stop immediately and work the problem, so you don't dig your own hole any deeper lol.

Now, whatever problem was there, is buried under additional coats. Most likely it will continue to fester under there, and result in the early failure of this paint job.

I know you say you did preparation, but it doesn't appear you had any viable method for determining if your prep was any good. For instance, sticking masking tape on the wall, rubbing it down and pulling it up - that is an example of a test for whether the old paint is fit for recoating. If it did, then you have more prep to do. But you didn't test that, so we'll never know.

Expect continued failures. The only real cure is to remove all the layers of paint down to the failing layer, but that's way more work than you say you are willing to do. So there you go.

Primer's job is to provide a uniform surface, so the final paint coat is also uniform.

Because if you don't use primer, and you have different areas with different color, texture or absorption, this will "print through" the paint, and will be apparent in the final job. The purpose of primer is to equalize all that. You're meant to use primer (and sanding as needed) until you have a consistent surface to your satisfaction.


If this was a newly plastered wall you dont use primer! So talking about doing a mist coat makes me think that's what's happened here. Definitely needs a mist coat not a primer! All that involves is just watered down matt emulsion and not vinyl any decent stuff you know if not B&Qs good home white matt emulsion is made by akzo nobel who manufactor dulux paints in Germany is a good one for the price decorators in the trade call it white gold. as emulsion is water based paint. You just add water anything above 30% of the paints total volume, 10ltrs 30% is 3 ltrs water added and stirred thoroughly. Myself I tend to do 50% sometimes even 60% the more water you add the trickier it is to apply. The reason you water the emulsion down (dilute) is because bare plaster is greedy! If you apply it as is its to thick and doesn't soak down into the plaster under the surface this then causes paints to just sit on the surface and any moisture on top of that first layers causes the first layer to bubble and peel off. This was a while ago obvs but for anyone else that lands here before doing the samething i hope this helps. I also hope he/she they/them 🤦‍♂️ got that primer off the wall or that wall is going to be a mess especially for how much plastering costs. If unsure research it pays off this goes to show that people who think if you can piss you can't are totally wrong.

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