What to replace drywall with behind new tub surround?
The tub-shower in a rental property has gotten so badly water damaged that the drywall above the multi-piece surround is moldy and crumbling, and there are numerous patches of mold on the ceiling and walls. I'm planning to rip out the surround and all the drywall in the bathroom (there are mold stains through the paint everwhere), and start from scratch. Of course, I'll also be installing an exhaust fan to help keep this from happening again.
My question is this: Which materials should I replace the old drywall with? I'm thinking greenboard on the entire ceiling (even over the tub-shower) and on all the walls *except* the walls immediately above the the walled sides of the tub. I'm not sure if I should install greenboard on these three walls or not. your thoughts? I'll be installing a new multi-piece surround.