It’s important you build a shower pan correctly. Unless this is done, it could lead to all sorts of problems. Start by getting the needed supplies.
Required Tools and Materials
Caulking and caulking gun
Chicken wire (or wire lath)
Concrete finishing trowel
First make sure the drain isn’t clogged. Get a clamping ring drain. Set the supporting flange of the drain at the plywood subflooring.
Use the mortar mix to make a sloped floor. The minimum slope for the subfloor is ¼” for every foot. Secure ¾ x ¾” float strips around its perimeter. These will be your guides as you build a shower pan.
Put the clamping ring on the subfloor. Fasten ¾” float strips at the shower floor edges. Apply 15 lb roofing felt. Put on the wire lath with staples.
Trowel the mortar. You can use wood float to pack the mortar in. Always use latex additive for the mortar mix; water is insufficient. Allow this to dry overnight.
You should use chlorinated polyethylene sheet membrane when it comes to the shower pan liners. Put blocking in the midst of the studs at the pan’s perimeter. The blocking needs to be at least an inch over the pan’s upturned sides. When you build a shower pan, the fasteners must be flush. Set the sides according to the local building codes in your area.
Lay out the membrane. Slice it to the right size. Trial fit it on the floor. If it’s all right, take out the membrane. Fasten the membrane clamping on the drain’s lower portion. Put a bit of rubber sealant at the drain flange. Put the membrane in place. Crease the extra material and staple it on the wall. Put some sealant at the folds to keep it in place.
Put the prefabricated dam corner at the point where the shower curb meets the membrane. As you build a shower pan, put a couple of 1/8” beads (half an inch spaced out) of sealant on the membrane. Use the trowel to set the dam onto the sealant.
Set the fasteners on the upturned edges. Slice the bolt heads projecting from the drain. Firm the membrane over the bolts. Secure the bolts and make a hole in the membrane.
Thread the drain screen in the clamping ring. Put pea gravel at the drain base. Float 50% of the deck mud. Put down some reinforced wire and put the other half of the deck mud on it. 16/16 gauge 2 x 2” mesh will be just fine. You can also use 16/13 11/2 x 2” or 13/13 gauge 3 x 3” meshes. Now float it on the slope.
The final step to build a shower pan is to notch the wood float’s front edge. This will allow it to ride at the bottom part of the wall.