Internal Wall Plaster Coat Missing

[wassupjg]

Hi, any help much appreciated.

Upstairs room (semi detached) with outer facing wall has had damp issues in the past with mould - cause should be remedied now by problem roof tile and guttering issues. Doing some diy refurb many months later, I just applied (Dulux) Damp Seal to the wall which had been behaving fine up to now, which caused the underlying paint layer to bubble a lot. Scraping off a lot of the bubbling paint layers (wasn't plaster!), hope you can see from the pics I'm left with what I think is render which seems in strong condition with no crumbling, but hairline cracks all over which no doubt let moisture through. The render just seems to have been painted over the years, the quality of the finish has always been smooth and indistinguishable from the other plastered walls in the house, I wouldn't have known it hadn't been plastered. The paint on the render (with fetching floral design) seems to have left a smooth finish which all the other emulsions over the years have sit on. What's a simple but correct way to get the wall back to a normal white finish? Is there a render paint or does it have to have a plaster skim? Any insight greatly appreciated.

(looks damp but bottom right corner is dry)

 

[motorbiking]

That’s what passed as plater back in the day. It’s a grittier version than the multi finish we have nowadays. It’s a kind of lime sand mix.

you can do a mist coat to seal it before painting but you may need to sugar soap the powdery paint residue off first.

 

[JohnD]

(looks damp but bottom right corner is dry)

how do you know?

 

[Nige F]

That’s what passed as plater back in the day. It’s a grittier version than the multi finish we have .

grey siraphite