Plumbing a Kitchen Part 2 of 5
Plumbing a remodeled kitchen is a relatively easy job if your kitchen includes only a wall sink. If your project includes an island sink, however, the work becomes more complicated.
Overview
Plumbing a remodeled kitchen is a relatively easy job if your kitchen includes only a wall sink. If your project includes an island sink, however, the work becomes more complicated. An island sink poses problems because there is no wall in which to run a vent pipe. An island sink requires either a complicated configuration known as a loop vent or a device called an air admittance valve (AAV), now approved by most codes. An AAV eliminates the need for a loop vent in most island sink installations. Check with the local plumbing inspector before designing an installation with an AAV or a loop vent. For our demonstration kitchen, we divided the project into three phases:
• How to Install DWV Pipes for a Wall Sink
• How to Install DWV Pipes for an Island Sink
• How to Install New Supply Pipes
Our demonstration kitchen includes a double wall sink and an island sink. The 1 1⁄2" drain for the wall sink connects to an existing 2" galvanized waste-vent stack; since the trap is within 3 1⁄2 ft. of the stack, no vent pipe is required. The drain for the island sink uses a loop vent configuration connected to an auxiliary waste-vent stack in the basement.
From: The Complete Guide to Plumbing, 978-1-58923-378-2
Step 1
How to Install DWV Pipes for a Wall Sink
Slide banded couplings onto the cut ends of the waste-vent stack, and roll back the lips of the neoprene sleeves. Position the waste-T assembly, then roll the sleeves into place over the plastic pipes.
Step 2
How to Install DWV Pipes for a Wall Sink
Slide the metal bands into place over the neoprene sleeves, and tighten the clamps with a ratchet wrench or screwdriver.
Step 3
How to Install DWV Pipes for a Wall Sink
Solvent-glue the drain pipe, beginning at the waste-vent stack. Use a 90° elbow and a short length of pipe to create a drain stub-out extending about 4" out from the wall.
Step 4
How to Install DWV Pipes for an Island Sink
Position the base cabinet for the island sink, according to your kitchen plans. Mark the cabinet position on the floor with tape, then move the cabinet out of the way.
Step 5
How to Install DWV Pipes for an Island Sink
Create the beginning of the drain and loop vent by test-fitting a drain trap, waste-T, two 45° elbows, and a 90° elbow, linking them with 2" lengths of pipe. Measure the width of the loop between the centerpoints of the fittings.
Step 6
How to Install DWV Pipes for an Island Sink
Draw a reference line perpendicular to the wall to use as a guide when positioning the drain pipes. A cardboard template of the sink can help you position the loop vent inside the outline of the cabinet.
Step 7
How to Install DWV Pipes for an Island Sink
Position the loop assembly on the floor, and use it as a guide for marking hole locations. Make sure to position the vent loop so the holes are not over joists.
Step 8
How to Install DWV Pipes for an Island Sink
Use a hole saw with a diameter slightly larger than the vent pipes to bore holes in the subfloor at the marked locations. Note the positions of the holes by carefully measuring from the edges of the taped cabinet outline; these measurements will make it easier to position matching holes in the floor of the base cabinet.
Step 9
How to Install DWV Pipes for an Island Sink
Reposition the base cabinet, and mark the floor of the cabinet where the drain and vent pipes will run. (Make sure to allow for the thickness of the cabinet sides when measuring.) Use the hole saw to bore holes in the floor of the cabinet, directly above the holes in the subfloor.
Step 10
How to Install DWV Pipes for an Island Sink
Measure, cut, and assemble the drain and loop vent assembly. Tape the top of the loop in place against a brace laid across the top of the cabinet, then extend the drain and vent pipes through the holes in the floor of the cabinet. The waste-T should be about 18" above the floor, and the drain and vent pipes should extend about 2 ft. through the floor
