I need to move my DWV about 6" to accommodate for a larger bathroom size but I dont want to relocate the stack in my roof. I currently have a 4" copper main vent. I want to cut off as close to the top (roof) as possible and the bottom (basement) of the copper and replace with PVC. What fittings do I need in order to join the PVC back to the copper?

You would purchase shielded couplings/clamps... see images.

You would order 4" PVC x 4" copper shielded transition clamp.

In most states, if you are getting this inspected, you can use the transition clamp in the basement, but you can't usually use the 2nd clamp in the attic. It is expected that you will continue out the roof PVC.

If the job is not to be inspected then you can certainly get away with using the 2 transition clamps. If a home inspector objects years down the road when you sell the place you can deal with that then... :)

Shielded clamps can also be referred to as MISSION CLAMPS or some will call them fernco proflex clamps, but don't confuse the shielded fernco with the all rubber and two SS bands fernco... they are NOT the same! Use SHIELDED CLAMPS only. For the size you need you will DEFINITELY need to go to a PLUMBING SUPPLY STORE!

MARK

MARK