Moving a tub drain

Discussion in 'Shower & Bathtub Forum & Blog' started by Waltman, Oct 29, 2007.

  1. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    I need to move my existing tub drain to the other side of the alcove to accommodate my new tub...long story.
    Drain is 1.5" ABS, need to run 6', thru about 4 joists (2x10). Not the least bit interested in notching the joists...

    How do I tie this into the existing? (45*, 90* ??). I am assuming I need to remove existing trap and relocate with new drain as double traps are a no-no...

    Need suggestions for spanning thru the joists...
    Is 1.5" hole saw good, or should I go bigger for wiggle room?
    I'm not sure the 6' run will flex enough to get thru all the joists in 1 piece...should I cut & glue in some couplers? Is this good practice?

    Slope-- do I need to slope this new section?

    Vent -- PLEASE say I don't need to mess with the venting!!!

    Glue -- is there an ABS primer??? Should I use it? I've seen ABS cleaner, should I use that??? I already got the word on making sure I use ABS GLUE!!! <-- another long story!

    Thanks All!
    Last edited: Oct 29, 2007
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,128
    Location:
    New England
    I think the max distance between a tub trap and the vent is 5', but double-check that. If so, then yes, you do need to consider venting as an issue. It would be far easier to build a chase in the ceiling downstairs to hold the pipe - you will not get a single piece through those joists, and depending on what you have, you may not be able to do it at all. That section DOES need to be sloped at 1/4" per foot back to where it ties into the drain system, and with the additional length, may not work without other changes.
  3. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    The chase option is out of the question as this bathroom sits atop the dining room. A soffit in this location would be unsightly.

    The 1.5" slope difference is going to be an issue as the existing drain exits thru the joist appx. 1.5" from the top already.... ACK!!!

    What "other" changes do I need to look at to make this work out??? I'm thinking I could build up the floor, this also creates the illusion that the tub is deeper. But other than that, I'm not sure if there's anything I can do to without major surgery...which I aint gonna do...I'll send the tub back first!!

    Can/should I section & glue the new drain using ABS couplers or is this unacceptable?

    Venting is not a show-stopper, but I'd prefer NOT messing with it as my best solution would look like a train wreck :)
    Last edited: Oct 29, 2007
  4. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    AHA!!!

    Another option I MAY have is to tie into the existing 2" shower drain. This drain is less than 4' from where the new tub drain needs to be.

    Now...is this a no-no???

    Is there such a thing as a 2" TO 1.5" ABS tee. This would be with the 2" running strainght thru, with the 1.5 branching off at the 90*....

    If this is doable and allowable, this could be the answer I need....

    *** UPDATE *** this may not be so doable because the only tie-in I would be able to get would be on the horizontal. I DONT have access to the vertical stack. I suspect a horizontal tie-in is not allowed. If it is, please tell me how to tie a 1.5" tub drain into a 2" shower drain on the horizontal, it wouldn't be a straight run. I would need to get around existing shower p-trap.

    ANYONE????
    Last edited: Oct 29, 2007
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,128
    Location:
    New England
    The tub would still need to be vented prior to connecting it to the shower drain. Wait for the pros on how to do this.
  6. frenchie

    frenchie Jack of all trades

    How big are your joists? You may have no choice but to mount the tub raised.

    Your holes have to be maximum 1/4 of the joist size, and have to be at least 2" away from the top or the bottom of the joist.

    If you need to run the hole closer than 2 inches from the top or bottom... presto, it's a notch. And a notch has to be smaller than 1/6 the joist.


    I don't know so much about the plumbing - but I do know that codes on venting vary a lot. Ask the local building department.
  7. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    Here's a pic of the job. Now, we're all on the same page :)

    The tub will need to be 'flipped' so that drain is on left hand side. This needs to be done in order to meet mfr spec for service access to pump & plumbing.

    THANKS AGAIN ALL!!!

    Attached Files:

  8. patrick88

    patrick88 Plumber

    Messages:
    836
    Location:
    Webster Ma.
    Just glue

    You would need to use a tee wye or wye. They do make them.

    Yup you can do it. See above. The tee can't be on its side flat must be turned just a little.

    I don't know NJ. venting rules but I'm sure somebody will know if you can hold out for a while.
  9. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    Patrick,

    Thanks!!! I'm having trouble visualizing. Please help me a bit more. Also, I would be using a SANITARY TEE, not a VENT TEE...correct???

    Even if the shower drain I'm tying into is 4' away, I may still need to vent?

    Slope of 1/4 is assumed too, correct?
  10. frenchie

    frenchie Jack of all trades

    It's not a sanitary T or a vent T, it's a whye - the arm is at 45 degrees - you put another 45 on that, to get 90. The idea is to avoid a sharp turn, which would slow down the water flow.

    There's also such a thing as a long sweep T, which accomplishes the same thing.



    (Where are the plumbers, these days? I keep expecting Grumpy or Mark or Kordst or Terry...)



    The carpenter (me) is still waiting to hear how big the joists are...

    Attached Files:

  11. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    Joists are 2x10 dimensional lumber...no engineered joists.

    If need be, I'll raise the tub 1.5" by placing 2x4 or 2x6 dimensional on their sides as sleepers.

    And it's totally cool to use the wye, or long sweep wye to tie into an existing drain on the HORIZONTAL run??? I assume the wye needs to face downline so as not to shoot the drainage toward the existing drain...

    Yes, I assume A LOT!!! That's why (not wye) I'm here!!!
    Last edited: Oct 30, 2007
  12. markts30

    markts30 Commercial Plumber

    Messages:
    630
    Location:
    Phoenix, AZ
    Enlarge the pic so we can see it (or at least I can - seems like I am going blind...*sigh*) and then draw in what you have already in place as far as piping and some dinensions...
    From that we can give you some valid answers...
    Without that our answers are all "maybe you can do this" and "maybe you can do that"...
  13. frenchie

    frenchie Jack of all trades

    A 2x10 is actually 9-5/8", call it 9-1/2"...

    So the biggest code-compliant hole that you can make in it is 2-1/8"; so you're fine doing 1-1/2".

    Staying at least 2" away from the top or bottom of the joist, there's 6 inches you can put it into: plenty of room for the 1/4 per foot drop.

    You're set.

    Now you just need to work out the venting question.
  14. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    New, hopefully larger image for those vision impaired :) DIDN'T WORK!!

    Frenchie - My existing tub drain is already <2" from the underside of the subfloor :-(
    To extend another 6' I'll still need to bump it up another 1.5" hence the need to still build up the floor....

    Now, to connect to the shower drain, I don't think I have enough room to put the wye on an angle. Won't know for sure until I pull the floor up...still have fingers crossed that this will work...

    Mark, sorry I am having problems resizing my image...more detail coming, please gimme a few.

    I oughta just pull the permit and pick the inspector's brain on this....
    Last edited: Oct 31, 2007
  15. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    with PICTURES

    Let's try this

    Attached Files:

  16. Nate R

    Nate R New Member

    Messages:
    472
    Location:
    Milwaukee, WI
    IIRC, 1.5" DWV pipe out of ABS or PVC would have an OD of 1.9", so a 2" hole saw is required.
  17. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    Pictures::: :)

    For reference, post #15 shows "the Plan"...

    First Pic: Overview of existing shower drain (left side) and proposed new tub drain (right side) Note:: Vertical stack in rear is NOT vent, it's a passive radon stack.

    Second Pic: Shows proposed new tub drain less than 3' from existing shower drain. I'd like to somehow tie into this shower drain to service the tub.

    Third Pic: Shows clearance of existing shower drain to underside of subfloor (appx 1.5")

    I'd need to get thru 2-3 joists (2x10 dimensional lumber) depending on the path I choose.

    Any suggestions??? :confused:

    Attached Files:

  18. frenchie

    frenchie Jack of all trades

    Okay, now I get it.

    Honestly? I think you're screwed - at least as far as tying in to that shower drain. You can't go put a 2" hole that high on a 2x10 joist.

    At least I wouldn't, without getting an engineer to give me specifics on how to reinforce the joist afterwards.

    Only other way I can see is, if you build up the floor enough to run the new pipe completely above the old floor.

    Or run it a completely different way, over to wherever the shower drain leads? Then you'll definitely have to vent. In fact, I think you'd need to already, depending on where the vent for that shower is.

    Out of curiosity, what's downstairs?


    edit: is there a reason you can't tie in to the old tub drain location? It's about 4' the other way, right? How far under the floor is that pipe?
  19. Waltman

    Waltman New Member

    Messages:
    34
    Location:
    South Jersey
    French.

    Only other way I can see is, if you build up the floor enough to run the new pipe completely above the old floor. I was thinking I could raise the tub about 1.5 - 2" on sleeper studs then notch as necessary thru the joists. I think a build-up is inevitable at this point.

    Out of curiosity, what's downstairs?
    My Dining Room is downstairs... UGH!

    edit: is there a reason you can't tie in to the old tub drain location? See comments below
    It's about 4' the other way, right? (about 5' yes)
    How far under the floor is that pipe? THAT pipe (1.5" dwv) is only about 1.5" under as well. The other issue I may have is that the dwv will need to loop-back under the tub and may interfere with the brass tub drain assembly.

    edit: At this point, do I just get the inspector out and discuss my code compliant options, or just hire a plumber and be done with it??? BTW How much would a plumber charge for something like this?? (I'm in NJ)
    Last edited: Nov 7, 2007
  20. frenchie

    frenchie Jack of all trades

    I'll probably catch flak from some of the regulars for this, but... My personal rule is to never let a plumber attack framing. Slogan: "nothing strikes fear, in the heart of a carpenter, like seeing the plumber go by with a sawzall in his hands..."

    No joke: that's how you wound up with the holes 1-1/2" from the top in the first place!

    It might be good to get a pro's perspective on the drainage/vent issue, though.


    Why would it need to loop back? Not sure I understand...


    If you keep notching your way up, you'll be severely weakening those joists.

    Talking to the inspector is a pretty good idea, he can see the whole structure and maybe give you some ideas.

    They're usually pretty DIY-friendly, if only because most homeowners don't bother applying for permits, so they want to encourage your conscientious behaviour... your mileage may differ, but it's worth a shot.
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