Bed the Membrane Along the Back Wall of the Shower
Next I spread thinset in back of the drain on top of the drain membrane and up onto the waterproof wall board about 6 inches.
After precutting 12-inch wide strips of the membrane, I cut one to the length of the shower wall and pressed it into the seam between the floor and wall. The membrane overlapped the drain membrane by more than two inches.
To ensure complete adhesion, I went over the membrane with a taping knife, smoothing the membrane and squeezing out the excess mortar.
Bed the Drain First
Piecing In
