Modifying Bathtub Drain and Overflow Kit

Discussion in 'Shower & Bathtub Forum & Blog' started by CM2304, Dec 20, 2011.

  1. CM2304

    CM2304 New Member

    Messages:
    10
    Location:
    Pennsylvania
    Hi -

    I'm in the middle of a bathroom remodel and I've removed the floor down to the joists. I tore out the old cast iron tub and am in the process of replacing it with a Kohler acrylic tub. I realized too late that the drain on my new tub is centered almost exactly over a joist. I absolutely do not want to cut or modify the joists. I'm putting down natural stone so I'm concered about the stability of the floor. The tub is in an alcove, but I don't want to bump out the tub since then I would have to drill the joist for the drain pipe, which would then be located on the opposite side of the joist, and I dont want to do that.

    The custom overflow kit I bought for the tub is copper pipe. I figure I can cut the two sections of pipe (the drain and the overflow) and solder in a few 1 1/2" 45s to jog them off to the side of the joist, connect to the brass sideways "T" fitting that came with the kit, and then drop down to the P-Trap.

    I know that there is such a thing as a "side discharge" drain kit. I actually looked at one today in the plumbing supply house, but it costs $70. I don't want to spend alot of money on a solution to this problem since I already paid alot for the custom overflow. Plus, I would really only need the base fitting part of the side discharge and I would still have to make room for the drain pipe under the tub.

    Is my plan advisable or am I just asking for trouble putting any bends in the drain line before it reaches the "T" fitting? Assuming the bend isn't a problem, is this plan otherwise ill-advised for any reason?

    Thanks in advance for any help
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,262
    Location:
    New England
    If you ever need to snake the drain of a tub, it is usually done from the overflow. WIth extra angles in there, that may be impossible.
  3. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,259
    Location:
    Land of Cheese
    Is it the tub shoe or the vertical drain that is over the joist?
  4. CM2304

    CM2304 New Member

    Messages:
    10
    Location:
    Pennsylvania
    Thanks for the replies. The tub sits parallel to the joists - they run the length of the tub, so the tub shoe and the vertical drain would both be almost directly over the joist.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,026
    Location:
    Cave Creek, Arizona
    What KIND of drain is it? If it is a "trip lever" you could NOT offset the overflow pipe. Your drain is NOT the same size as 1 1 1/2" solder copper 45s, so you would have to use "slip joint" 45 degree "offset" tubes.
  6. CM2304

    CM2304 New Member

    Messages:
    10
    Location:
    Pennsylvania
    It's not a trip lever. It's the pop-up, toe activated kind. The overflow/drain kit that I bought is the one that is required for this tub. The tub has an oval shaped overflow opening as opposed to the traditional round opening - hence the need for the custom kit. The overflow part of the connection actually has a flexible ball joint type connection where the pipe meets the oval shaped overflow fitting. This feature permits the overflow pipe to move a few degrees to either side during installation - but not far enough to solve my problem. I'm not sure why this feature exists, other than perhaps to provide some flexibililty during installation.
  7. kreemoweet

    kreemoweet Member

    Messages:
    374
    Location:
    Seattle. WA
    What's your plan for soldering DWV-size copper pipe attached to an acrylic (=plastic!) tub? That requires
    substantially more firepower (i.e. plastic-melting heat) than does supply-size copper tubing. It's hard to
    imagine getting the required precision if done off the tub. The standard thing would be to cut and header
    off the offending joist. You're not putting stone under the tub, are you?
  8. CM2304

    CM2304 New Member

    Messages:
    10
    Location:
    Pennsylvania
    I decided to go with this fitting, which I found at the local plumbing supply house.

    Attached Files:

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