If you are remodeling your bathroom and also discover that the shower will be set up over the place of the preceding toilet, you can just change the toilet drain to a shower drain. The 4-inch PVC of the toilet drain will need to be reduced to 2 inches for the bathtub, so that you unless you have access under the restroom by means of a basement or crawl space, then you’ll need to cut a few of the subflooring to produce the pipes changes under the ground.
Turn off the water supply to the toilet, and remove the supply tube by tilting the couplers with an adjustable wrench. Flush the toilet to remove most of the water, then loosen the nuts to the closet bolts, and lift the toilet off of the toilet flange. Scrape any wax ring left to the toilet flange, then loosen the mounting screws with a power drill and pry out the flange with a pry bar.
Access the toilet plumbing from under the ground from the basement or crawl space, or locate the nearest floor joists using a stud finder and cut out the subfloor up to the two floor joists with a reciprocating saw to acquire entry to the plumbing beneath the ground.
Cut the 4-inch toilet drain pipe back about 12 inches in the elbow below the place of this old flange with the reciprocating saw. Wipe off the burrs in the end of the rest of the pipe in the cut, then apply PVC primer to the end of the pipe in addition to the internal edge of a 4-inch to 2-inch PVC reducer. Put a ring of PVC cement around the pipe, and connect the reducer to the pipe.
Gauge the distance from the end of the reducer to the middle of the desirable place to your bathtub drain, then subtract the distance in the middle of the vertical tailpiece of a 2-inch trap to the end of the trap in this span. Add 2 inches to the number, and cut on a bit of 2-inch PVC to match.
Apply PVC cleaner to the inside of the reducer and the exterior of one end of the pipe section, then glue one half of this combined and connect the pipe to the reducer. Connect the drain end of the snare to the end of the pipe in precisely the same method.
Check the degree of the PVC pipe in the reducer to the drain with a torpedo level. Attach the pipe to the floor joists with pipe straps using 1 1/2 inch screws, holding the pipe at a 1/4-inch drop per foot of run to allow the water to gravity-flow through drain properly.
Gauge the distance from the surface of the trap to the anticipated floor of the bathtub. Subtract the height of the shower drain kit in this span, and cut another part of 2-inch PVC to match. Prime and install this piece to the close of the trap.
Separate the shower drain and install the PVC foundation of the drain to the short pipe above the trap with PVC primer and cement.
Replace the subfloor in case you had to remove some sooner by chiseling out the subfloor along each joist so you have half of each joist to act as a nailer for your subfloor. Cut a sheet of plywood of the same thickness as the present subfloor to coincide with the size of this opening, and screw it to the joists using 1 1/2 inch wood screws before proceeding with the setup of this shower.