@orenjiAi , this sounds very similar to, what I do. I´m also coming from TS2 and TS3, and sometimes it was a really nard way to get familiar with the building system in TS4, especially this room based stuff. I was used to erect walls, not rooms. ut if it weren´t that bugged, I indeed think, that thinking in terms of rooms isn´t that bad. And like you wrote: Closing the ceiling with a roof always prevents the "exloded" room from being not recognized as part of the inside of a building.