I am currently using V.5. The newest model. I tried adding a 3rd floor, but it bacame clunky when I removed the walls. Next I looked under construction. Messed aroung with a few things but nothing was there. I don't want the roof in the ceiling, I want it ON TOP of the second floor. I tried to watch a tutorial video but it was unavalible. Some of the problem may be that it is a 2 story. I will also upload a picture of my floor plan. When you customize ceiling, you can only do one room at a time.I also looked in the catalog for some pre-made roofs, but there were none. (i think it would be a good idea to make them)