lol, this is crazy, somehow, something worked. Read right through to see what I did ( I just had this all typed up ready to post when I tried one more thing lol)
Mind if I ask for a screenshot of the final outcome? I've really gotten into building so I'd love to experiment with how this is done. I'm on disabled with insomnia so I have plenty of time to experiment lol
This is what I'm starting with, a simple single room downstairs and two rooms on the upper floor. At this point, there is a ceiling for both upper rooms and I can select each as a room. I can also delete the floor in one (which I'm about to do with the floor that is yellow)
In this one you can see how removing just on piece of wall changes everything. I took this pic in the wrong order and had to backtrack to remove the floor, but with or without the floor, the result is the same, the ceiling is now gone and I can't select the room on the left as a room now and so I don't get the option to add a ceiling.
If I choose to replace the wall with a fence (just grabbed one that was easy to see here) the reslt is better. The ceiling remains.
However, as soon as I remove the piece of fence over the stairwell, it's bye bye ceiling!
I had resigned myself to having this setup with the glass fence as that little piece over the stairs isn't too bad.
So, I'm not sure what triggered it, but while I was typing this reply, I realised that the picture that showed how once the piece of wall was gone, you couldn't select that area as a room, also still had the floor! I wondered if I'd be able to select the loft area as a room or if it would react the same. So I went back into the game and removed the piece of fence over the stairs only to have the ceiling remain!
Oddly though, the dark patch on the ceiling returns when there are windows in the open area. Strange, but I can live with that lol