How to Install a Shower Pan

Installing a shower pan involves removing the old pan, preparing the subfloor, setting the new pan in mortar bed, and connecting the drain assembly with proper waterproofing.

  1. Strip Away the Old Pan. Turn off water supply and remove shower fixtures. Cut through caulk around the pan edges with a utility knife. Remove tiles or surrounding wall material as needed. Disconnect the drain assembly and carefully lift out the old pan. Clean all debris and old adhesive from the subfloor.
  2. Verify Solid Foundation. Check that the subfloor is level, solid, and free of damage. The floor should slope toward the drain at 1/4 inch per foot. Install blocking between joists if needed for support. Apply primer to the subfloor according to manufacturer specifications.
  3. Route Water Away. Position the lower drain flange and mark its location. Cut the drain hole in the subfloor using a reciprocating saw or hole saw. Install the lower portion of the drain assembly through the floor, ensuring it sits flush with the subfloor surface.
  4. Build the Bed. Mix dry-pack mortar to a consistency that holds together when squeezed but crumbles when disturbed. Spread mortar evenly across the subfloor, creating a slope toward the drain. The bed should be thick enough to support the pan but thin enough to maintain proper slope.
  5. Lower and Level. Carefully lower the shower pan into position, ensuring the drain hole aligns with the drain assembly. Press firmly but evenly to set the pan into the mortar bed. Check that the pan sits level and maintains the proper slope toward the drain.
  6. Seal and Check Flow. Apply plumber's putty around the drain opening and install the upper drain assembly through the pan. Tighten the connection according to manufacturer specifications. Run water to test for leaks and proper drainage before proceeding with wall installation.
  7. Waterproof the Perimeter. Apply waterproof membrane or sealant around the pan edges where it meets the walls. Install backer board or cement board on the walls, ensuring it overlaps the pan lip. Apply final caulk bead around the perimeter for a watertight seal.