In Sims 3 if we didn't want the weather to come in, we had to build a ceiling for the room that had the greenhouse roof. But in Sims 4 what is the requirement for those glass roofs? Do I have to a...
As long as the ceiling is there before placing the roof, as with any other roof, you should be fine. The glass swatch or whatever you want to call it automatically 'removes' it after, but keeps the environment out. :)