Emulsion Blown And Peeling

[Ric.ror]

I’m trying to re- emulsion a wall but some of the previous paint has blown and is peeling off the wall right down to the plaster. I can’t emulsion over as that makes it worse
Help please

[Ken4155]

Sounds like you may have a damp patch there, Ric. Was the plaster newly applied when originally painted?

[Ken4155]

New plaster should be given time to dry completely - any patches that are darker than the majority of the surface area is deemed to not be so. Once dry, a light sanding is advised, followed by a mist coat of white matt emulsion - thinned with 10% - 15% of water, well mixed. This seals the new plaster and allows the first coat of silk vinyl to take hold. A second coat is then much easier to apply.
If the plaster where the problem occurs is dry, sand it down, paint the area over with a mist coat allow to dry before applying top coat.

[Ric.ror]

It’s not newly plastered and the last emulsion was added at least 15 years ago
It can’t be damp as it’s an internal wall in a first floor flat with no other signs of damp

[AuntLydia]

If its in patches it could be damp coming in or condensation. An 'Elastoplast' job would be sand off the flaky bits, apply a barrier such as unibond 5:1 with water, leave to dry 24 hours then emulsion over. Doing this though may result in the original cause of the flaky bits coming back.

[Ken4155]

Ric; "It's not newly plastered................................."

You haven't said whether you are using silk or matt but the sanding/mist coat treatment will work for both. Just make sure you allow plenty of time for the mist coat to dry before applying the next coat.

[Ric.ror]

It’s Matt emulsion
I do have a tendency to be very generous when applying the paint too

[Ric.ror]

It’s not a bedroom as there is no window - it’s just for storage - it houses the meters too and it’s not on the outside wall

[The Builder]

Usually two things that cause this, Ric.
Original plaster was "over-trowelled". Plasterers are often keen to "bulls***" the finish (technical term.) Most likely anywhere around mid to eye-level, so people can go up to it and remark on how wonderful the plasterer is. A shine is unnecessary. It prevents the paint from taking properly.
The second thing is a first coat that's far too thick. Ken's right about the "mist" coat. With thick, trade paints it's better to thin even more than the manufacturers say. Maybe 20% water. This coat should not cover. It's Ok to actually see through it. Subsequent coats can then be full ones.

Nothing for it but to attack it with rough sandpaper and scrapers to remove ant other paint that wants to leave the wall. Feather the edges of the remaining paint, then either seal with dilute PVA (not really the best way, as walls shouldn't be sealed...........
or .............. put on a new mist coat.

[The Builder]

^^^^ "any other paint"

[Ric.ror]

Ok - I should have made it clear the plaster is fine it’s my painting that’s the problem - now I know it’s my over generous application that’s the problem !!
Time to get the sander out I think
Thanks so much for your answers