Need Sch 40 “blind” flange help

Home Forums Public Forums Drainage & Sewerage Need Sch 40 “blind” flange help

  • This topic has 3 replies, 4 voices, and was last updated 21 years ago by RJKing.
Viewing 3 reply threads
  • Author
    • #278507

      I am replacing a shower with a tub on a slab. Of course the drains no longer align, so I have cut open the concrete to give me room to make changes. The existing cast iron trap has a rubber seal to capture the drain tailpiece as the fixture is lowered onto it. Not knowing the right term here, I call that a “blind” flange. I need to re-align it about 13″, and I have enough vertical space to do it. I would like to insert a 90 degree street elbow into the existing trap, come over the distance I need, and terminate in another “blind” flange to allow the new tub tailpiece to slide in. Then I can concrete this all back up again. All of this is 2″ stuff.

      Question: Is there such a thing as a “blind” flange in schedule 40? I don’t want another trap, just the flange part to capture the tailpiece.

      I could plumb the drain so that the tailpiece itself wraps back under the tub the 13″ and I could re-insert back into the existing trap, but then I have a concrete issue, having to leave vertical space under the tub for all this.

      BTW – This is obviously not my profession, but I love doing all manner of construction, from design to framing to sweating (pipes, too), through electrical. My wife is not so in love with my passion, but has come to accept and support it.

      Can you offer advice on this?

    • #298652

      Ok dont be bashful with your opening. Expose the trap completly and remove the rubber thingy (techinical terms) LOL

      Get a Mission coupling 2″ IPS 11/2 copper. DO NOT REPEAT DO NOT GET A FERNCO coupling even if it is given to you for FREE

      Check your local code book by the way as you may have to file this job or you can put your C of O in trouble at a later date.

      When you get your new fixture (TUB)
      ask your plumbing supply for a “Lay down tee” sometimes called a back outlet tee. Now all you have to do is get a heavy duty slip Ell (waste bend ) 11/2 36″ long and cut it to your needs. Get “LAMP WICK” not quick wick Packing and recto seal #5 with a 11/2″ nylon washer with 11/2 BRASS nuts dont use the white metal garbage.Out of the “run” of your back outlet tee you can use a straight piece of 11/2 tubing with another brass slip nut and lamp wick and washer. If you buy a 36″ long slip ell (waste bend) you will have enough tubing for not only the ell connection but the horizontal piping also. GET Heavy gauge tubing as you honestly dont want to have to open the floor for many years. TEST the tub several times by letting the water go out through the over flow before closing up your work. Keep the ells to a bare min as you really dont want to impede the flow of the waste. PERSONALLY I would have a Master plumber check your work Prior to closing any floors or walls. It is well worth the service call for insurance and peace of mind. Have fun and visit the loop.


    • #298653

      One thing to consider when making these offsets, is, “Is the plumber going to be able to rod this contraption some time in the future when it plugs up?” Ideally the trap should either be under the drain opening or in line with the overflow pipe so a drain snake has a straight access into the waste line.

    • #298654

      I’m getting the impression from more than one source that I may be better off to move this cast iron to align the trap with the tailpiece of the tub. That becomes a straight shot down the overflow tube, as the drain tees into the overflow. BTW – This is a Kohler tub – the one with the door on it.

Viewing 3 reply threads
  • You must be logged in to reply to this topic.

Pin It on Pinterest

Share This