Blisters in emulsion

[jonny513]

Hi all

Have just re emulsioned a wall in daughters bedroom as time for a colour change and quite a few blisters have appeared as if the paint underneath is lifting from the plaster, seems worse on one wall than another. Wondering what the reason is for this and what to do re the other two walls i have yet to start. Have taken the worst wall back to plaster as was such a mess, is it ok to emulsion straight on to plaster or do i have to seal 1st as the B&Q paint i'm using advises.

Cheers

 

[JohnD]

a watered-down mist coat is always advisable as it soaks into the surface.

look for any signs of dust or dirt and clean off.

 

[joe-90]

The main problem is that the original coat hasn't adhered to the wall properly, so when you paint over it, it expands and forms bubbles. I find the best way is to use an oil based primer over it so that subsequent coats won't reactivate the original coat.