I am installing a floating vanity and need to move a 1 1/2 vent line behind the wall. I am in a row townhouse.

How do I run the 1 1/2 pipe around the corner? Do I cut a hole in the studs or notch them?

One side has a 2x6 the other side has a 2x4.

The side with the 2x6 is an exterior wall and side with 2x4 is adjoining with another townhouse.

In the picture I included the new routing of the pipe.

Thank you!

enter image description here

  • Notched studs typically need repair to meet code. You'll cut holes, but even then you may have code issues with the 2x4 wall. It's very unlikely to be an actual problem, but....
    – isherwood
    Mar 1 at 14:51
  • Can you go up from new location and tie in to old above the wall?
    – Kris
    Mar 1 at 14:56
  • There isn't any plumbing above this powder room unfortunately.
    – Asif10
    Mar 1 at 15:19
  • Where is the riser? How did the drain and vent line shown in your picture work together before you came along? Is there a riser in the right hand wall? Did the drain formerly connect there? Where does the new drain, shown in your floor, go? It must attach to a riser at some point, and the venting should be handled at that point. More info on the pipe layout before and now would help.
    – jay613
    Mar 1 at 15:21
  • There used to be a vanity here, so these two pipes were connected with a sink and p trap in between, all of this was above the floor. The pipe on the left is the drain for the water and the pipe on the right was the vent pipe. I am not sure what the riser refers to.
    – Asif10
    Mar 1 at 15:42

Vent lines have to be "vertical" (where vertical is defined as 45 degrees or more, rather than what vertical normally means) until they are "6 inches above the flood rim of the highest fixture on the floor served" so the horizontal routing evidently below the sink level shown is not going to pass inspection, AFAIK.

You would have to run up at (at least) 45 degrees to the appropriate level before you can go horizontal.

The framing there looks like you would have major issues keeping it concealed in the wall. I gather that the "floating" nature of the new vanity prompts the desire to conceal the pipes differently. I'd strongly suggest considering a vanity that does not require structurally difficult rework - or else going straight up the wall cavity and doing the cross connect above the ceiling.

  • Thanks Ecnerwal. The venting (pipe on the right) actually goes into the wall and straight up. The water was originally draining through the pipe on the bottom left, as a result, the venting was situated above the drainage pipe. Hope that clarifies it somewhat
    – Asif10
    Mar 1 at 16:01
  • Point being, you can't just take that vent pipe horizontally over to the other wall at that level. If above the wall isn't an option, a soffit/pipe chase just under ceiling level is another option that does not involve trying to plumb through structural corners.
    – Ecnerwal
    Mar 1 at 16:09
  • 1
    "I'd strongly suggest considering a vanity that does not require structurally difficult rework - or else going straight up the wall cavity and doing the cross connect above the ceiling." Plus eleventy!
    – FreeMan
    Mar 1 at 17:02

This is perhaps a question of aesthetics, but you could route the pipe in front of the studs, at 45deg, tightly against them. Use all-round to hold it in place.

You could shape the drywall panel around the pipe protrusion, where it goes around the corner, and mud directly over the pipe.

Your drywall panel is 1/2in, and the imperfect corner will show a small bulge, which you could eliminate entirely by notching the stud corner by 1in. So no hole needed, just a round-ish or v-shaped notch out of the corner, which structurally should be no issue if kept under 1in.

The final look will depend on the type and width of the vanity, whether it's flush against the wall, and the wall finishing. If you'd be comfortable notching the vanity corner a bit, this may be a workable option.

  • Thanks P2000, I decided to heed the advice here and not cut into the studs. I am rerouting it around the corner since it's just the venting. Thanks for all the help everyone!
    – Asif10
    Mar 2 at 16:19
  • 1
    @Asif10 that's great. Nice to read some feedback. Remember you can upvote all answers that you like. We hope to see more questions and answers from you.
    – P2000
    Mar 2 at 16:40

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