Hello all, hoping someone out there might be able to help me out. So I'm trying to remodel my bathroom. I've removed the prefab shower and gutted to the studs and the sub floor. After laying plywood, I'm planning on installing one of those "goof-proof" shower pan kits from The Tile Shop. I'm going to be using Hardie board for the walls of the shower, but, while two of the walls have studs I'll be able to screw into, one of the walls is cement. Can I simply lay some thin set, put up the hardie board, let it cure and then screw it in? Do I really need to create a vapor barrier? Can I use 1/4" hardie board for the wall b/c I'm laying it over cement and I'm not worried about it bending? Any help would be most appreciated. Thanks.