I need to extend my bathroom sink drain about a foot further from the vent stack. It is copper and I am wondering if I can just attach a plastic fitting to the horizontal pipe or do you recommend extending it with copper pipe. My house is built in 1960.
I do not want to have access it again in the future so I have to do it right.
Thanks
Tracy

Hi Tracy

Use a copper x PVC shielded clamp... see image and run it in plastic (PVC). These couplings are reliable and code approved for the job you present.

Mark gave you the easiest way to go but if you want to "do the job right you'll remove the copper and run the drain in PVC. Good luck, Tom