I have a Gullringshus from 1970. I'm planning to renovate the living room and want to install a smooth plasterboard ceiling. The existing ceiling consists of elongated beveled "masonite panels". When you lift the masonite layer, it seems each board has a frame and a panel above, it appears to be like thick panel modules.
Above these panel modules, it seems there is only a thin paper/plastic mat and then insulation.
How are these panel modules connected? Are they glued and the whole thing just attached to the rafters? No battens? How does it hold together in such large sections? If they are attached to the rafters, how are they attached to the rafters?
In the kitchen, there is plasterboard that the previous owner has screwed directly into the frames of these panel modules, does that really hold?
Do I need to install battens to ensure the plasterboard stays securely in place?