Emulsion paint peeling off back to plaster when sanding

[Frednewton]

Hi, am lightly sanding an emulsioned paint wall prior to repainting, but the paint keeps peeling off right back to the bare plaster. I've now got a huge area without sound edges. House is 1989, probably two previous coats on the wall. No damp. Any tips, please?

 

[sparkwright]

Sounds like a mist coat wasn't applied in the beginning to the bare plaster.

You can 'fill' then sand the bare patches to get it reasonably flat, but applying the new paint COULD cause some of the old paint to bubble up.

All bare plaster and filler should be primed with a diluted matt emulsion.

Some experimentation will be required, to see if the old paint decides to lift, so watch how it goes before you apply the final coat.

 

[Frednewton]

Thank you for your advice. I did exactly as you suggested and it has worked fine.