How to Install the Clamping Ring Drain After the Removal of the Fiberglass Pan

Kneel down and measure the existing shower drain hole in the shower floor ensuring that it is the same diameter as the clamping ring drain. If needed, enlarge the opening with a handsaw or jigsaw. Do not damage the pipe inside the hole.

Unscrew the clamping ring drain’s three sections and turn the bottom flange piece upside down. Apply a one-eighth inch layer of waterproof plumbing adhesive to the rim’s underside and around the circular base. Turn the flange back over and insert it into the floor hole with the rim resting on top of the floor and the tube over the pipe in the floor. Pressing it down firmly secures the adhesive.

Apply a one-quarter inch bead of silicone caulk in a circle around the drain opening. Leave a 1-inch gap between the two.

Lay a shower pan liner over the area, allowing 2 inches to rise up one each wall. Press the shower liner into place with your hands. Feeling around the drain opening locates the bolts in the drain flange’s top. Pressing down on the liner punctures it, so that the bolts poke through.

Cut through the liner using a utility knife exposing the inner hole and all the bolts on the drain flange. Insert the clamping ring’s middle portion into the hole and twist it clockwise locking it in place over the bolts. Tighten each bolt head firmly.

Insert the strainer into the top of the drain and turn it clockwise engaging the threads until it reaches the height of where your mortar bed will rise.

Cover the entire drain with a piece of clear plastic protecting it. Pour the mortar bed.