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Painting over PVA
UncleFista - 17/7/09 at 01:20 PM

The cowboy who plastered my bathroom seems to have used PVA to seal the new plaster.
Since being painted (with emulsion) it cracked and flaked a bit in the corners. Today I thought I'd hoover the worst of it off and touch-up, unfortunately, where the hoover nozzle touched, it sucked all the paint off the walls/ceiling !

Looks like I'll have to decorate again, at least the paint stripping will be easy

What can I do to stop it peeling again ? Some type of barrier coat, sand the walls (please no !) any suggestions gratefully received


tegwin - 17/7/09 at 01:38 PM

Um.... stick some lining paper to the walls...then paint it?


twybrow - 17/7/09 at 01:43 PM

I'm no expert, but PVA is water soluble, so just wash all the walls really well with a mildly soapy solution. Once done, do a small test area before painting everything. We had a similar problem in out bathroom- pain started peeling in the middle of the wall. the soltuion - we bought a bigger mirror!


Ray - 17/7/09 at 01:44 PM

Hi you need to seal the plaster with PVA to seal it. also mix some up in your emulsion when putting it on works a treat

cheers Ray


UncleFista - 17/7/09 at 01:58 PM

quote:
Originally posted by Ray
Hi you need to seal the plaster with PVA to seal it. also mix some up in your emulsion when putting it on works a treat

cheers Ray


I've always sealed new plaster with watered down emulsion and I've never had any problems before.
It's possible to feel the PVA on the plaster, maybe he used too thich a mix, and it wasn't absorbed ?


thunderace - 17/7/09 at 02:19 PM

you paint the wall with 1/10 pva then plaster the wall (pva it to help the plaster bond to the wall)
the plaster it may bleach through (the pva)mix more pva 1part pva to 10 parts water then paint the wall it will dry in clear and the flake pva will wash in then paint the wall problem solved easy.

you cold just wash the walls it water based .


andy o - 17/7/09 at 03:26 PM

what he said ^^^


Litemoth - 17/7/09 at 03:59 PM

The not-so-great plasterer may have 'polished' the wall. That means he's left a shiny keyless finish on the wall that causes peeling. It's a common problem if you're painting as it's only meant for papering onto.

Get some fine sandpaper or that 3M plastic sandy cloth stuff and quickly rub the walls to key the surface - its a fairly painless procedure and will cure the problem. PVA on top of plaster in bathrooms isn't a great idea as it's broken down by water.
Try 'kitchen & bathroom' paints as they're better suited to wet environments.


ibakes - 17/7/09 at 04:15 PM

I can plaster and have done quite a few jobs, the most common problem I have heard from people is that they have never been told how to paint on to fresh plaster.

Fresh plaster will dry the paint out too fast and cause it to flake off.

PVA is water soluble and can be painted over without any problem

You need to water down the first few coats of emulsion, start with a rough 50/50 mix, this will help to seal the wall and stop later coats of emulsion drying out too fast.

keep making the mix stronger the more coats you put on to get the colour you need