How do I waterproof my bathroom walls?

Applying backer board, liquid membranes, or foam sheet membranes behind the tile, and along shower, openings are all ways to waterproof your shower walls. The waterproofing method you select will depend on what type of tile you choose and your skill level. If this step is missed you could see severe damage from molding and mildew. You should consult your contractor or professionals for these implementations.