How to Build a Concrete Shower Pan
If your home has a shower pan that is made from tar paper, you may want to replace it with a concrete shower pan. A concrete shower pan won’t break down or leak the way other materials can.
Starting the Shower Pan
To lay a shower pan properly you need to have a sound wood or concrete floor. The first thing you’ll do is to lay roofing felt over the floor. Mix 5 parts sand and 1 part cement and slope it in the direction of the drain. Place the pan in the mixture and even it out over the sloped mixture.
Wrap the sides of the pan up along the walls for 10-inches. Wrap it over the ledge of the door step. Fold the corners and the seal them so they are water tight. After that you’ll place a mortar bed over the pan, tilting it towards the drain.
Crushed Stone and Tile
Putting crushed stone around the drain will keep water flowing towards the weep holes. Next install the wall over the floor so that you can use a flexible sealant where the wall overlaps onto the floor. This will make an expansion joint. It’s best to use flexible sealant rather than grout at each point that walls join at an angle.