old bare plaster - mist coat?

[Saytan]

Looks like the ceiling in my converted loft wasn't misted after being plastered, i picked at a bit of damaged paint and now it's coming off in sheets

i think it's around 10 years old. I'm erring towards mist coating it before painting it properly, but wondering whether it may now be dried out enough not to.

 

[JBuk]

The mist coat is still needed to prime and seal the plaster and give your emulsion a better bond , that is why the current paint is coming off, I have the same problem with the ceiling in one of my bedrooms and I’ll need to completely strip it , lightly sand then seal/prime it

 

[Saytan]

thought as much. I've got 10L of cheap white emulsion somewhere so that'll do.