(Similar to this question here)

I am renovating a bathroom, and I'd like to put a pedestal sink in, instead of a full sized vanity. The primary issue is I would have to move the drain pipe, it is a cast iron drain pipe that is currently on the wrong side of an interior wall stud.

I have full access to the wall in the bathroom, so I can get at pretty much any part of the piping, but I'm not sure how to handle the stud and changing the iron piping.

Here's a picture of the way it looks now (what pictures would help?)

enter image description here

The bit of PVC you see sticking out immediately connects to the aforementioned cast iron pipe, it broke while I was trying to remove it.

Here's some more pictures: enter image description here enter image description here


2 Answers 2


The stud you would use a hole bit that is the same size as your piping to cut a circular hole. You can pick up these bits at big box or a place like Harbor Freight in the US.

You do need to make sure that the stud is not load bearing! If it is or could be we need more info and pictures.

It really looks like you have PVC but we can't see everything. If you need to go from PVC to cast iron use a coupling.

  • Oh yes, I'll add a quick note about that in the post, but basically it had a PVC pipe sticking out of it (that I accidentally broke while removing), but it's cast iron immediately after the lathing.
    – Dugan
    Aug 21, 2013 at 22:29
  • Just cut the iron so that it is flat going same direction as wall, put on a coupling and route your pvc through a hole you need to drill.
    – DMoore
    Aug 22, 2013 at 0:59
  • I added some pictures
    – Dugan
    Aug 22, 2013 at 2:00
  • Also the second picture is your vent. You will add a T to your PVC in the wall to reach the vent.
    – DMoore
    Aug 22, 2013 at 3:55
  1. Cut a hole in the obstructing stud (the "beam" in your pic #1) for your new PVC pipe. Make sure this hole is the in right spot so you still get the correct slope to the vertical cast iron pipe (you want at least 1/4" per foot). Make sure it is not load bearing, judging from your pictures it looks like it is not load bearing but you will have to determine that for yourself. That stud looks like it is really just a nailer for the lathe (pic #3 shows it is not a solid piece and the dimensions are a little funky).

  2. Cut the cast iron pipe, probably with a chain pipe cutter since using a saw will be really tough. Install a flexible coupling (aka "Fernco Fitting") with a metal jacket (this is required because you are going to cover this up in the wall) to transition from cast iron to PVC.

  3. Plumb it out the rest with PVC. Be sure the new trap is not too far from the vertical vent to vent properly. If it is you may need to make 2 holes in the stud and run a drain pipe and a vent pipe from the new sink location back to the cast iron pipe.

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