I have recently removed a vanity from my bathroom and am facing an unfortunate plumbing footprint when trying to put a new vanity in place.

The cold water line runs right against a built in cabinet which I would like to keep in place and the drain for the sink is also the drain for the bathtub in the upstairs bathroom. So the drain pipe actually comes out of the wall and then into the floor.

My question is will I be able to remove enough material from a new vanity to fit it in this space or will I compromise the structural integrity of the vanity I am trying to install.

The previous vanity that I removed was custom built to fit in the space, ie extra pieces of wood were attached to an old piece of furniture and a piece of marble was cut for the counter top. Believe me it sounds nicer than it looked.

Here is an image of what I am dealing with.

Photo from above Photo from floor underneath

  • It all depends on what's inside the wall and why they didn't run the plumbing inside the wall to start with.
    – BMitch
    Commented Jan 5, 2014 at 21:15
  • Well looking at it from the basement there is a hot air vent which runs up the wall right where those pipes come up so putting it in the wall there is unfortunately not an option. Also, there is a bunch of ducts which runs right under this bathroom. I had looked into trying to move the supply line on the right over about 2 to 4 inches to give me a better footprint but I dont think I can get a torch and solder in there. Not sure how big of a job pulling out some of the ducts would be, but it looks like that would be required to reroute the pipe, unless I can do it from above.
    – Jebadiah
    Commented Jan 6, 2014 at 0:58
  • Here is an image of what I have under the floor. You can see the hot air duct that runs through that wall. Moving the pipe over several inches would probably make this a non issue with Jack's suggestion but I am not sure how easy it would be to solder in that tight location.under bath
    – Jebadiah
    Commented Jan 6, 2014 at 2:08
  • I'd suggest editing your post to include the additional photo rather than posting a link to flickr. The link can go bad and make this question more difficult to follow by future visitors. I'd add it myself, but you have it covered by a copyright on flickr.
    – BMitch
    Commented Jan 6, 2014 at 16:05
  • 1
    Do I understand that the white pipe coming out of the wall is the drain for a second floor bathtub? If so, wouldn't an obstruction below this point cause the tub to empty backwards through the sink drain onto the floor?
    – DJohnM
    Commented Jan 7, 2014 at 0:47

4 Answers 4


Cut that pipe out in 2 places. One place is above the bottom shelf of the new cabinet and mid way between the 2 fittings on the upper pipe that goes at a 45 degree angle. Recouple it back together when the cabinet is installed. The supply lines need to be relocated too, but you may be able to move them around to get past their issues.

The cutting of the vent pipe is still taking a small chance it will be difficult to get the pipe back together. As it is you will need to shorten the pipe you cut out at least by a 1/2" to make room for the stop built in as part of the coupler. You will also need to account for how much out of square the cut has too.

If the upper portion of the pipe has a little upward give to it, it will be a lot easier to rejoin. If not you will need to be really assertive on getting it back together again.

  • This seems to be a great answer. It reduces the work from modifying the vanity to just one hole drilled out for the drain and it reduces the plumbing work to making two cuts and adding two couplers. The only objection I can raise is that its another non-standard job whereas relocating the plumbing to the wall makes it right.
    – Freiheit
    Commented Jan 6, 2014 at 16:54
  • 2
    @Freiheit, I would prefer that everything be relocated into the wall and floor as it should be, but he asked how to get the cabinet around the pipes. I presumed there were issues to keep from reworking the plumbing.
    – Jack
    Commented Jan 6, 2014 at 23:40

I would probably just cut out section of subfloor around this mess, and the section of drywall, and then re-route everything (under the subfloor) so the pipes come out of the wall. It's not that difficult, and it's probably less work than modifying cabinets and doing the creative plumbing necessary to get this to work.

Of course, this might also mean replacing the flooring (if you intended on keeping that), unless the new vanity can completely hide the patch.

This would also give you the option of using a pedestal sink, which might be appropriate because of the tight space between the wall and door. Personally I prefer the "euro style" vanities in this situation, but just throwing it out there anyway.

  • I had posted above, unfortunately it looks like they ran the supply lines up through the floor because a hot air duct goes up the wall right there next to those supply lines.
    – Jebadiah
    Commented Jan 6, 2014 at 1:04
  • You can run the lines through the joists to get into the next bay, if necessary (or even to come up in through the floor in a better place). Just keep in mind the guidelines for holes in joists, and that you might need a right-angle drill.
    – gregmac
    Commented Jan 6, 2014 at 4:25
  • Based on your photo from underneath, you don't even have to go through any joists, so it should not be too bad to route the lines up next to the vent (where the drain line enters the wall now). I would still cut out a rectangular section of the floor boards in this space to do the work from above (from the wall to the joist underneath), then patch it back up with a piece of OSB/plywood.
    – gregmac
    Commented Jan 7, 2014 at 18:36

Cutting three small holes out of the bottom of the vanity is in no way going to affect the integrity of the vanity nor is it bad practice. I come across bottom plumbing from time to time.

The chances are there was a reason that they couldn't put the pipes in the wall - most of the time it is the wall sitting on a joist.

  1. Cut your pvc out so that you have about 10 inches sticking out of floor.
  2. Cut pvc so there is a couple inches stick out of wall.
  3. Drill small hole for copper line. For the one of the right make sure that you do not drill vanity base.
  4. Drill out back hole for pvc.
  5. Take off valves off copper lines so that you do not have to make huge holes for them. If soddered on then just cut them off below.
  6. Need one person holding vanity and the other guiding the pipes in.
  7. Finish underneath plumbing.

Have never had an inspector say a word about plumbing straight to an unfinished area - basement. It isn't normal but its certainly not helping your plumbing situation by moving everything. It is just money and time spent for possibly more issues.

  • +1, the only problem I see is the supply on the right, in the corner. That may need to be moved; cutting out the corner of the cab risks instability. Cutting off almost the entire back panel is fine.
    – Mazura
    Commented Apr 24, 2015 at 1:05

Looks like it could be a project to reroute the pipes. I would modify the new vanity. Just attach it to the wall good. Would be a good idea to add a nailer to the other side of the pipe

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