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Painting & Decorating

Paint not adhering to walls after damp treatment

We recently had a couple of walls treated for damp, then re-plastered. I followed the builder's instructions to wait a few weeks until fully dry, and then to apply a mist coat before painting with emulsion. When I went to paint this area using a roller, sections of the plaster have started to flake away - specifically in the area where the damp work joined the existing untreated wall. I contacted the builder who advised me to use a powder filler to smooth out any imperfections and then repaint. I've done this and the wall looks even worse, with areas starting to bubble. The builder came back to inspect and said that he can't see any evidence of a mist coat, and that the paint has not adhered to the walls. He advised me to sand down the area and start again, however my decorating skills are pretty basic and I'm not sure they are up to the job. Any advice? The wall has been checked again to ensure the damp hasn't spread, and that doesn't seem to be the issue.

4 Answers from MyBuilder Painters & Decorators

Best Answer

Sounds to me like who ever plastered the wall, over polished the plaster during the final stage. This causes paint not to adhere to the surface. Even without a mist coat the paint would still stick. All I can suggest is lightly rough up the surface to be painted. I tend to use a bare plaster paint from screwfix which is thick and allows the surface to breathe prior to painting over with your desired colour.


Answered 15th Mar 2020

if it's the plaster that's came away from the wall that sounds as if the plaster hasn't adhered to the damp wall or there is still a damp problem
with out seeing it it's hard to say
you could try sanding down using a primer/sealer or a product called guardz or a oil based undercoat
again these are just guesses without seeing it


Answered 15th Mar 2020

You have to really water down the emulsion for the first cote to let the paint and plaster dry together try useing eclipse and dont forget to water it down


Answered 15th Mar 2020

Hi there, I would advise you use a product like Zinsser Peel Stop or Zinsser Gardz once the wall has been rubbed down to a smooth finish. Then I would use a Primer like Zinsser balleye 123 over the affected area and a little beyond. That will seal and prime the wall before you apply any paint.
If the problem persists after this, it may have something to do with the plaster.
Hope this helps you and good luck with sorting this problem


Answered 15th Mar 2020

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