Help - paint flaking off the celing when I apply new paint!

[HelenJenn]

Hi

I have decided to re-decorate my bathroom, starting with the ceiling. There is currently matt emulsion on and I am painting over with silk. When applying the silk paint with a roller it is taking off the old matt paint - so that the plasterboard is visible??

I have decided the the best thing to do is scrap off all the old paint - when I have done that do I need to apply anything before applying my new silk paint?

Also before I even started painting some small parts of the old paint had flaked off - it was only decorated 4 years ago by the builder when the house was built.

Please help??

 

[54aardvark]

Hi HJ and welcome.

Also before I even started painting some small parts of the old paint had flaked off - it was only decorated 4 years ago by the builder when the house was built.

I think this is the clue to your problem - from the sound of it the plaster wasn't sealed prior to painting - happens a lot with new builds. The plaster is hygroscopic so it sucks all the moisture out of the paint and it doesn't have a chance to penetrate the surface and consequently the solids just lie on the surface.

You've got the right idea, scrape off all the loose paint and then seal the plaster beneath. You can use a specific plaster sealer or, cheaper and equally effective, use a mist-coat. Mist coat is simply a non-vinyl emulsion diluted by 40-50% with water, give it a coat of that then dilute your next coat by about 20% then a couple of coats of whatever you fancy. Personally I avoid the specific bathroom paints as they tend to be more expensive and can be difficult to get an even finish.

Whatever you do, don't use PVA to seal the plasterwork!