Bathroom remodel with wall hung toilet. Need advice on plumbing and venting.

Discussion in 'Remodel Forum & Blog' started by TCor, Mar 10, 2014.

  1. TCor

    TCor New Member

    Messages:
    5
    Location:
    TX
    Hey all,

    I'm new to posting on the forum but have been following for a couple of years while I've been remodeling my house. I'm about to start on a second floor bathroom and was hoping for some specific feedback and advice. I've demoed the existing plumbing (which was inadequately vented) and I'm adding a wall hung toilet along with the proposed plumbing. The only existing/remaining plumbing is the 3" drain and the lavatory plumbing with 2" vent which are shown on the diagram in red. The situation is tough in that there is limited space in the trusses between floors as well as a header for a first floor window. Consequently, I think the best solution is to tie the tub and toilet together and add another vent that would tie into the existing 2" vent above the lavatory. Also, due to space the lavatory needs to be tied into the main drain below the truss space and in the first floor wall.

    My specific questions are...
    • Does the attached plumbing diagram adequately and correctly drain/vent the fixtures?
    • Does a sanitary double wye work for tying the tub, toilet, and vent together? (It should be noted that the distance between the vent and both tub and toilet is less than 2')
    • Are the line sizes appropriate? Specifically, is the vent size adequate? The current vent for the whole bathroom is 2" but could be upsized if necessary.
    • Also on that note. I will be doing the second bathroom after which is the same except a 1.5" vent from the kitchen sink ties into the this bathroom's 2" vent. Is that 2" vent adequate for tub, toilet, lav, and kitchen sink?

    Any other thoughts or anything I'm missing? Thanks for your help!

    Terry

    photo copy 2.jpg
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,513
    Location:
    Cave Creek, Arizona
    A "sanitary double Y, or sanitary cross or double combo for that matter, are ALL improper fittings, and in many areas you could not use an elbow behind the toilet, it would be a sanitary tee or carrier fitting, and it could not connect above the tub drain unless the tub had its own vent. Who determined that the old plumbing was "improperly vented"? The key question, however, since this appears to be an "added" bath, is there an existing bathroom downstairs? IF the answer is , YES, then you have to throw the whole drawing away and start over.
  3. TCor

    TCor New Member

    Messages:
    5
    Location:
    TX
    Hey hj,

    Thanks for the reply! These would be the only fixtures on this stack and I'm just remodeling the existing bath with the main change being a wall hung toil. Sorry for the simplified drawing but the fitting for the toilet is where the toilet carrier would be. Here is what the plumbing looked like before... This and the wall hung toilet are the reasons for the plumbing re-do...

    photo.jpg
    Lav and tub wye in after closet bend and only vent is above lav, which is about 7' from tub.

    With that being said, would my only issue be the sanitary double wye? I could possibly go with a configuration like the following and provide separate vents for both the tub and toilet.

    Carrier.JPG

    Essentially starting furthest upstream it would be the following tying into 3" drain: tub drain... tub vent... toilet drain... toilet vent...then 90 to soil stack where lav would tie in per original diagram.

    Also, would the original 2" vent be adequate for entire stack or do I need to upsize to 3"?

    Thanks for you help!
  4. TCor

    TCor New Member

    Messages:
    5
    Location:
    TX
    This might also work...

    Unknown.jpeg
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,513
    Location:
    Cave Creek, Arizona
    If the "toilet vent" is NOT connected directly to the toilet riser, then it is cosmetic, thus serves no useful purpose, and is either not necessary or in the wrong location. As long as the shower drain is vented, that vent SHOULD serve to vent the toilet, although in your case, given that the toilet has a fairly long drop, some areas would require a vent off the toilet's "stack" at or below the elbow. In other words, the way you show it in the second picture, while not how I might do it, may satisfy the requirements in your area. Only the building department and inspector can tell you for certain. 2" vent should be adequate.
  6. TCor

    TCor New Member

    Messages:
    5
    Location:
    TX
    hj...

    Thanks again for all your help! I think I found a way to incorporate all your suggestions and fit everything in the truss and wall spaces. Here is the final drawing in which I've eliminated the sanitary crosses, added a vent for the toilet off the soil stack, and tied in the tub and lav downstream on the stack.

    plumbing diagram.jpg
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