The shower pan is the base or floor of the shower. Shower pans can either be purchased as one solid unit or they can be custom made from scratch. Shower pan floors are made with built-in liners to prevent leaks, and they are usually covered with a fancy tile or granite. Quality shower pans are built with a slight slope toward the centre where the drain is located to ensure the water always flows toward the drain. If you are building your own shower and are worried about constructing your own custom shower pan, don't be.
Place a 3/4-inch piece of plywood over the top of 2-by-10-inch joists to create your floor. Measure and cut the plywood to size with a circular saw. Our shower floor is 4 by 4 feet. Make sure there is a hole in the centre of the plywood for the drain.
Lay down a slip sheet to cover the entire surface area of the plywood floor. You can use plastic garbage bags or roofing felt. Cover the slip sheet with wire mesh cut to fit the area. Use a staple gun and randomly staple both materials to the plywood.
Put together the bottom flange of the clamping drain assembly. Follow the instructions that come with the product.
Pour a latex additive, found at any hardware store, into a bag of mortar mix and mix it up in a wheelbarrow with a shovel. Use the latex additive instead of water to provide double the compression strength.
Use the shovel to fill the shower bed with the mixed mortar. Build it up to about 1 1/2 inches around the outside perimeter and create a slope down toward the drain. All of the moisture within the shower pan will flow toward the drain. Pack the mortar tight. Let the mortar cure for a day.
Put a shower pan liner, sold at any hardware store, over the mortar bed. Let it drape up the sidewalls about 12 inches. Fold over the excess liner at each corner and place a staple at the highest section of the liner through a nearby stud. Fold the liner down over the shower curb and staple the liner only on the outside.
Carefully cut a hole in the centre of the liner for the drain with a utility knife.
Finish the custom shower pan by filling the area with deck mud. Deck mud is made by mixing five parts of sand to one part of cement and water. Work the mud so that there is a 1 1/4-inch layer around the drain. Don't forget to maintain the slope of the pan.
Spread and pack the mud with a trowel, being careful not to cover the drain or the weep holes. Use a level around the perimeter as you trowel the mud to make sure it is even all the way around. This is the final layer of your shower pan, so make sure it is flat and smooth.
Take your time to make sure each layer of the custom shower pan is laid properly. Each step must be perfect to have a perfect final product.
Do not get any mortar or mud into the drain hole. Cover it with duct tape for better protection.