Shower Pan

Ever wonder what was under your shower floor to keep the water in? Well it differs depending on what your shower is made from. In our case, we'll have a tile floor and walls. To prevent leakage (tile really isn't waterproof), the builder puts a waterproof "liner" made from polyethylene. It's about 1/8" thick and is being tested here to see if it is water-tight (and it is). They simply plug the drain and fill it with about 2 inches of water and let is sit to see if there are any drips underneath.

The builder will create a "mud pan" by using a type of cement to form the base for the tile floor. I've never done one, but I suspect the liner will be trimmed so that it is actually up under the green drywall and wall tile they install. That way there won't be any leakage between the wall and shower pan.