
The outer wall are 20cm of concrete mass. The only ''problem'' I've over there is the window space and the other concrete wall is attached to the neighbours. That STC is almost impossible to beat. The other walls are from thinner concrete mass but also 20cm thick. I think, but correct me if im wrong, that building a complete structure in the room is a waste of time, material and result. The only thing that concerns me is the door and window. But I think every studio has that problem.
For now I will start with a frame to make the build a little bit easier; few cm airgap, 5/10cm of isolation (Rockwool) and one or two layers of drywall. Or do I create a drum again then with the walls?