Damp, platering or painting issue?

[Blue_Manc]

One exterior facing wall is having issues with paint "Bubbles".

Wall is about a foot and a half thick, stone construction. Interior walls plastered then painted (Before I moved in).

Bubbles appear, which if touched the top coat of paint crumbles off. Underneath there is a sealant type paint, which peels off as a solid layer. When peeled off there is usually a white powdery residue on the plaster behind.

Any ideas on the problem, and how to fix - don't want just to cover over.

Pics below. Thanks in advance. (nb Please keep replies low tech - complete novice here )

 

[do_it_yourself]

Hi mate, looks like you have the same prob as me:

check this out.

//www.diynot.com/forums/viewtopic.php?t=113204

The solution - first find where the damp is causing the efflouresece and halt it.

Next i got rid of it with efflourescent solution, then cos it was soo bad i touched up the 'dents' with polyfilla, then painted the whole wall with black bitumen paint - then undercoat and paint over.

that was nearly 2 years ago and thus far its fine. However I do expect at some stage to reline that part of the wall with plasterboard with anti damp coating