Wanted:Underground Lot, Tiki Hut

Hmm, so, sad news. You can't place a roof underground, no matter how deep you go. The best that you can do is build a glass roof on the ground level, which would let you look inside the club itself from above, but once you went down one level, the roof would be gone. Sorry. It's a cool idea, just not something that can be achieved in the Sims 4, unless there is some sort of cheat I'm not aware of.

Cheers,
Ro