Hi,
Many years ago, my dad painted the bathroom walls with a gloss paint (possibly oil based - I don't know for sure, and he's passed away now so I can't ask him) to make waterproof etc.
Years later (with no problems from the paint), some tradesmen came in to do a wet room for them and painted over the top of the dark green gloss with a matt pale blue paint.
This resulted in mud like crazy crackle all over where I guess the green gloss repelled the new matt paint, which was probably acrylic. (Photo attached - as you can see it even went round the outline of where the old wall heater was).
A couple of years after, with advice from a local shop, I painted an undercoat primer on it and then a top coat. Eventually this resulted in the same crazy crackle effect. Now this would be good if that's what I wanted. but it looks awful.
I now want to get this fixed as best I can for now.
Some have said fill the cracks with filler, light sand, then paint.
Others think doing a skim of plastering straight over it will solve it, but then a plasterer I asked who was repairing another room in my house said that the plaster could end up crazy crackling too.
I just tried paint stripper on a little bit, which took it down to the green but I realise the green is painted on a wallpaper lining that's on the plaster, so probably not the best idea. I don't want to try to strip the wallpaper as I don't know what the walls are like underneath (it's an old house) and as eventually we'll do a full reno on the bathroom, it really is just to make it look cosmetically better for now.
Someone else said Thistlebond it, (and then paint it) but that's REALLY expensive and I don't want to go down that route if that doesn't work for this type of problem either.
Any advice would be most welcome.
Many thanks