Step 1: Prepare the Subfloor and Remove the Old Drain Pipe

Shower pans or shower bases feature a drain hole, typically set on a sloped floor to direct water to the hole. In our bathroom remodeling project, the subfloor is prepared and a shower pan is installed to accommodate an expanded shower.

Begin by positioning the shower pan in the roughed-in space and mark the position for the pan drain hole on the subfloor below. Use a jigsaw to cut a hole in the subfloor around the mark (Image 1). Drill one or two large holes in the subfloor.

The hole should be enough to reach into with a PVC saw to cut the old drain pipe. Have a helper watch from the floor below to make sure the saw doesn't cut through any remaining pipes or conduits.

Note: Always wear safety glasses and use caution when working with a jigsaw, drill or other power tools. The helper also needs to wear eye protection to guard against falling sawdust and debris.

Use a PVC pipe saw to carefully cut the existing drain pipe (Image 2).

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    Image 1

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    Image 2

Step 2: Complete Subfloor Prep and Install Pan

In our project, we needed to add a sheet of plywood to build up the subfloor and bring it level with the rest of the bathroom floor. To do this, cut a sheet of plywood to size and dry-fit it in the space. Secure it with construction adhesive applied with a caulking gun and screws. In our project, we used an impact driver to install the screws.

Set the new shower pan in place and mark the location of the new drain hole. Use a drill with a hole saw bit to make the cutout for the new drain (Image 1).

Position the shower pan and put the rubber gasket in place (Image 2).

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    Image 1

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    Image 2

Step 3: Assemble and Fit the New Drain

Cut the PVC pipe for the new drain to length and de-burr the cut end with a file. Dry-fit the PVC fittings. Once all of the PVC components fit properly, apply PVC cleaner to the surfaces being connected.

Follow this up with PVC cement, then slip the PVC pieces into place. Hold the pieces in position for a few moments while the PVC cleaner and cement mix to keep the reaction from forcing the pieces apart. Attach the new drain cover.