When changing your old tub shower to a shower stall, the shower drain will need to be relocated. Ensure that you have a plumbing permit, and get an inspection once the job is done. Follow these directions to reposition your shower drain in the center of your new shower base.
Step 1 - Remove the Old Tub and Shower Pipe
Discontinue the water supply to the bathroom. Remove the faucet handles and the water spout. Remove the shower diverter if it is separate from the water spout. Pull the tiles from the bathtub surround wall to expose the pipes. Disconnect all of the pipes from the tub. For a steel or fiberglass tub, tilt it up and lift it out of the enclosure.
Step 2 - Mark the Existing Shower Drain and New Drain Hole
Place tape over the existing shower drain. Set the shower base on the tub's subfloor and mark the location of its center drain with permanent marker. Sketch a plan of the new drain location on a sheet of newsprint.
Step 3 - Measure From the Old Drain to the New Drain
Measure the distance from the old tub drain to the new shower drain. Attach a length of 1.5-inch feeder pipe from the old wall pipes to the new drain hole. Mark a 12-inch access tunnel on the subfloor for the new feeder pipe.
Step 4 - Cut the Subfloor to Install the Feeder Pipe
Cut through the subfloor along the access tunnel lines. Lift the old subfloor pieces. Mark the location of the feeder pipe on the floor joists and cut through them with the 2-inch hole saw to make a clear path. Remove any nails from the path of the feeder pipe.
Step 7 - Attach the Feeder Pipe to the Drain and Shower Lines
Cut the 1.5-inch feeder pipe to the correct length. Attach it to the 2-inch shower line in the wall with a reducer, directly below the shower line. Install the P-trap at the end of the feeder pipe closest to the new drain. Run the feeder pipe to the new drain hole location, attaching a vertical pipe segment here. Cement all joints with waterproof plumbing cement. Hold plastic pipes still for 1 minute to let the cement set.
Step 8 - Lay the New Shower Floor
The inspector must approve the new feeder pipe and P-trap before you lay in the new shower floor. Once that is done, set the new shower floor base over the new drain and secure it with plumbing cement.