I am now also facing this choice.
Pure gut feeling advises me to go with a concrete ceiling, after all, I grew up in the East in a prefabricated slab building.
Besides, I am not a fan of wood. Wood can be infested by animals, catch fire, creak, etc.
With a concrete ceiling, however, there is the problem of floor insulation between stories.
The attic is expected to be used only as storage space, so it still needs to be walkable. What costs should be expected for this? Which material is suitable for this?
How did you decide???
Best regards
Judyyy