How to Install Commode Rough Plumbing
Commode, water closet and toilet sound sound like different appliances, but there is no difference when it comes to installing the rough-in plumbing that makes them work. Each one requires a cold water line, a drain line and a talented installer. In medieval times, the commode was a cabinet where the "chamber pot" was kept. That pot simply needed a "chamber maid" for installation. Does this Spark an idea?
Things You'll Need
- 3-inch PVC drain line in place
- 3-inch sweep PVC elbow
- Closet flange
- ½-inch cold water supply line
- Stub out and cap material
- Plumbing hanger
Instructions
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1
Select the commode to be installed and obtain the rough-in guide. If selection cannot be made before rough-in plumbing is installed, be sure to select a commode with a closet flange rough-in dimension of 12 inches.
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2
Cut a 3-1/2-inch diameter hole in the sub-floor, 12 inches on center from, and parallel to, the finished wall against which the commode will fit. If you selected a commode with non-standard rough-in dimensions, cut the hole at the distance from the wall specified.
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3
Install a 3-inch PVC sweep elbow with opening facing up at the hole onto the end of the PVC pipe serving the commode. Hang the assembly from underneath the floor so the top edge of the sweep elbow is flush with the top of the sub-floor. Be sure the drain line is pitched ¼-inch per foot. If the installation is in a slab, set the top edge of the sweep elbow to be flush with the top of the finished slab.
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4
Solvent weld a closet flange to the sweep elbow and bolt it to the sub-floor. If installing in a slab, wait until the slab is poured and then solvent weld the closet flange to the sweep elbow. Be sure the slotted portions of the closet flange are perpendicular to the wall. In both cases, if the finished floor will be higher than the thickness of the closet flange metal ring, shim the flange so that its top will end up flush with the finished floor.
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5
Install a ½-inch cold water supply line 8 inches high in the wall behind the commode, and 6 inches to the left of the closet flange center line (as you face the wall).
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6
Stub out and cap the supply line so it will protrude through the finished wall where a valve can be fitted later.
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Tips & Warnings
During rough-in, finished walls are usually not in place. Be sure to add the extra thickness of the finished wall to the existing stud wall when calculating where to cut the hole and install the sweep elbow and closet flange.
Follow local plumbing codes on venting and clean out locations. Installations can vary significantly depending upon plumbing materials chosen and how other components in the bathroom are plumbed. Follow safety precautions related to solvents and pipe cleaners.
