A Great Way to Waterproof Your Shower
There are many ways to go about water proofing your walk in shower. I like to us a mix of products and methods. Overall the base is mud and that mud is waterproofed after it is cured.
The walls of the shower start with half inch cement board that is glued and screwed into the studs. For the floor of the shower a mud base is made also know as a mud bed. The walls and floor of the shower are then covered with Kerdi Membrane, a product made by Shcluter. Niche shelve corners and shower corners get two coats of Hydroban a paintable waterpooring topical.
This may be a little extra than needed but it helps me sleep at night and damaged tiles can be replaced much easier.