We're currently having our bathroom remodeled and the contractors have put up durock/cement board everywhere they're going to tile. In the shower pan they put a rubber liner and what I'm assuming is concrete on top of that. But everywhere else they just have the cement board, on the shower walls, the floor, around the tub, etc.

I'm a bit worried because everything I've seen or read says that you have to water proof everything somehow, but it doesn't seem as if they are going to (they're about to start tiling). A former contractor friend I talked to yesterday claims he never used to water proof beyond the shower pan basically.

So, will the durock/cement board + thinset and tile on walls and floor be enough? Or should I insist on them doing more to water proof it before tiling?