Thanks guys
It's looks like I have to take it all the way back then.
What a pain... But I'd rather do it properly.
The ceiling is currently being replaced.
It was a conservatory with a plastic see through ceiling but now I have someone replacing it with a timber roof and they have insulated it...
I think I have uploaded a picture below. You can see the crumby sand like stuff in the top part and the plaster that on the surface looks ok but I think is crumby behind it.
Maybe I should point out that none of the pink plaster sounds hollow when I tap it
In my conservatory I have had an issue with penetrating damp.
We have found the issue and corrected it ( hopefully)
Now I need to get the walls decorated again.
I noticed a few hollow sounding bits of plaster so took them off and beneath it was what appeared to be solid plaster. Although some...