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p-trap extension

lmh129's picture

Installing a laundry sink to replace a normal bathroom sink. Drain hole of new sink is 7 inches farther away from the wall than old one. Do I need to extend the pipe from the wall (moving the p-trap 7 inches farther away from the wall), or can I simply add some sort of 7-inch extension in front of the p-trap and connect it to the sink drain pipe? Thanks.

p-trap at the drain, then extension (post #205797, reply #1 of 2)

Typically the p-trap mounts under the drain, and then an extension goes to the fitting at the wall. 

Offsetting traps (post #205797, reply #2 of 2)

Back in the Kitchen and Bath special, winter of 2004 I did a short piece on offsetting traps under kitchen sinks to allow for wheel chair access or drawers. I can't seem to find it on the FHB site but the basic deal is you use one side of a double sink waste to elbow back towards the wall directly under the basket strainer and then use a 1 1/2" trap adapter to connect to more robust 1 1/2" pvc piping and elbow down to a schedule 40 chrome nut tub trap close to teh floor and run it back into the wall as usual.

It's a little more complex if you are adding a dishwasher in which case you use the other side of the double sink trap to turn the tubular pipe down at the back of the cabinet and pick up the slip joint dishwasher tail piece before converting to schedule 40 with the trap adapter and tub trap.

There is a pretty clear sketch of the detail at my website here:


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