Tub drain to existing cast iron

Discussion in 'Shower & bathtub Forum & Blog' started by JMarine, Apr 6, 2014.

  1. JMarine

    JMarine New Member

    Messages:
    6
    Location:
    Bolingbrook, IL
    Hello all - long time lurker first time caller.

    Quick intro - I am a company pipeliner by trade (petroleum) so I know a little about pipe but wont insult the trade saying I know jack about plumbing.

    Onto the question:

    I have removed a shower stall from a slab grade bath and am left with a 4" cast iron p-trap. The last hub at grade before the waste stack turns to pvc says Tyler 4XH which I am guessing that means I have 4" extra heavy (thick walled?) pipe and fittings. What I would like to do is install a bathtub in this location and leave the cast iron in place. The drain looks like it will match up dead center with the tub (pure luck?). I want to install a gasket to go from ci to pvc but that is where I am stuck. Most tub drains to my knowledge go to the end of the tub where they meet the overflow pipe and then go to a p-trap - can I flip this around so that the overflow goes to the drain tail and run that straight down into a gasket in the ci hub?

    If removing the cast iron is the best approach what is the best method- pulling them apart (twisting with pipe wrenches) or breaking it with mini sledges

    Here are a few pics so y'all can see what I am dealing with.

    Thanks in advance for any info or advice you may have.

    p-trap overview.jpg p-trap side view.jpg
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,889
    Location:
    New England
    Removing a fitting from a hub can be done with a big torch (harder the larger the pipe), or by first making swiss cheese out of the lead with a drill bit(s), prying it out, then the fitting can be worked out. The actual waterproofing seal is made with oiled hemp rope (oakum) pounded tight, then lead poured over it (takes some special tools and skill to do it on the horizontal). XH does stand for heavy duty. Converting it to pvc would normally be done using a donut - finding one the right size is critical and they come in numerous incremental size - you may have to order one. The reason the p-trap is underneath the overflow, is that using that gives a straight shot if you ever need to snake the drain as removing the grate on the drain is not always the easiest thing to do.

    Or, if you cut a bit more concrete, you could snap the hub off, then use a nohub or Fernco rubber seal and convert directly to pvc there. If there are any raised cast markings on the pipe, you'd have to either grind them smooth or snap it further back- don't try to seal over them.
  3. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,937
    Location:
    North Vancouver, BC
    Good question. Not sure what Jim is trying to tell you but you best wait for Terry or HJ to answer your question.

    If you rig it like you are saying the overflow might turn the system into a S vent....
  4. JMarine

    JMarine New Member

    Messages:
    6
    Location:
    Bolingbrook, IL
    Jim - no lead joints here - all neoprene hub gaskets. The hub that is flush with the concrete is part of the main waste line and the pvc in the top of the pic is the vent. I hear you on snaking the drain but with 4" ci I would have to shave my girlfriends head to create a hairball that big.

    John I want to retain the ci p trap and run the drain tail directly into it using a donut.

    Here is a pic of what I want to end up with #58 going directly down to a donut and into the ci p trap, minus the sketchy flexible part:

    flipped drain.jpg
  5. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,244
    Location:
    Land of Cheese
    There is a reason every type of fixture has a designated trap size. The flow of water into the drain most be great enough to scour the trap and pipe clean. Draining a tub into a 4" trap will result in a stinking cesspool of a tub drain.
  6. JMarine

    JMarine New Member

    Messages:
    6
    Location:
    Bolingbrook, IL
    Well every house in the subdivision was built with a shower in this location (which obviously does not make it right) - I just removed it and figured that the original installers did not want to mess with different fittings. I can remove the existing trap I am just not sure of the best way to go about it without disturbing the existing waste line.

    Anyone know if the drain line setup in my last photo is legit? Problem I have with going with a standard drain setup is that the overflow comes right down onto the hub that I am tying into.
  7. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,937
    Location:
    North Vancouver, BC
    I have not seen that set up before. Sorry got nothing for you.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,889
    Location:
    New England
    I still think you'd be better off, and find the much more common (and probably less expensive) tub drain assembly if you removed the trap and whatever from the hub sticking out at the edge of your first picture. I described how to do that. If it's not a leaded fitting, all it will take is a bunch of prying. Then, you can get the p-trap exactly where you want it. The odds of finding a replacement tub where it will perfectly align with a new drain assembly in that non-standard configuration to the existing one are pretty slim. Certainly, you might get lucky.
  9. JMarine

    JMarine New Member

    Messages:
    6
    Location:
    Bolingbrook, IL
    Problem is I want to leave the main waste line intact - you can't really tell from the photos but the hub that trap goes into has short stub, I believe it is a santee. You can see the pvc vent at the top of the photo and that is the top center of the main waste line so the hub itself is only a couple of inches off the main line. I don't want to take my chances at cracking off the hub and not damaging the rest of the fitting.


    Well the tub lines up with the center of the existing p trap which is the first reason I thought of the donut - second reason is that I saw looking through a catalog that reducing p traps are made which made me think that it was ok to have a 4" trap with a standard drain (which is what I removed). The original cast iron drain adaption was pretty rotted out as the original pan was a set in place cast concrete(?) unit of craptastic quality.
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,889
    Location:
    New England
    You need one of the pros to guide you...what I would do and what they would do may differ, but you're better off with a drain nearer to the size of the drain opening than one over twice as big (tubs generally have a 1.5" drain, showers 2"). Remember, the area of the opening is a function of the square of the radius...it increases considerably with a seemingly small change in diameter.
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,485
    Location:
    Cave Creek, Arizona
    A Watco "green flex" waste and overflow has the drain exit under the tub outlet.
  12. JMarine

    JMarine New Member

    Messages:
    6
    Location:
    Bolingbrook, IL
    That is the sketchy flex I am referring to - have you used one of these in an installation? I call it sketchy due to lack of personal experience - if they have smooth insides and the flex section lasts then I don't see an issue with it. I just worry about the flex section rotting out.
  13. JMarine

    JMarine New Member

    Messages:
    6
    Location:
    Bolingbrook, IL
    Maybe I should have titled this thread - " how would you put a tub here?" Thanks for all the replies so far - anyone use one of the drain type setup that hj posed earlier? A lot of my searches keep turning up results from Europe and not so many local manufacturers.
  14. Smooky

    Smooky Member

    Messages:
    596
    Location:
    NC
  15. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,937
    Location:
    North Vancouver, BC
    Sorry - we have not used it before...
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