Spackle/concrete ceiling plastering?

[AlfredS]

Concrete roofs need a surface coating and eventually painting. Do you think I can apply filler directly, perhaps with some primer, or is it a better idea to have the mason apply plaster first?

As the picture shows, there are casting seams that can be sanded away, embedded boards, as well as some kind of cork along the exterior walls. Otherwise, smooth concrete.

 

[Stefan N]

You will probably need to remove cork and wood first in any case.

 

[AlfredS]

You will likely need to remove the cork and wood first in any case.

The cork is present in all rooms along the exterior walls, and the other rooms have textured ceilings, so apparently some materials adhere well even to the cork. I assume it serves some insulation function.

 

[skaraborgsfakir]

Concrete roofs need a surface layer and eventually need to be painted. Do you think I can plaster directly, maybe with some primer, or is it a better idea to let the mason apply gypsum plaster first?

As the picture shows, there are casting seams that can be sanded off, embedded boards, and some kind of cork along the outer walls. Otherwise smooth concrete.

Is there asphalt felt between the floor structure and the foundation wall?

 

[AlfredS]

Is there asphalt felt between the joists and the foundation wall?

Not that I can see.