Concern about slope

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by denikar, Feb 8, 2013.

  1. denikar

    denikar New Member

    Messages:
    13
    Location:
    Canton, MI
    Hi all,

    Great forum. First time poster with an issue that has been worrying me for a few weeks. I'm installing a new 2nd floor bathroom and have been following the latest Michigan plumbing code. The issue is where the shower drain meets the tub drain I mistakenly drilled the next joist hole too high. Now the "T" there is perfectly level instead of sloping down by 1/4" per foot per code.

    Here is a side view of the "T" in question:
    Bathroom Project 088sm.JPG

    Here is a perspective view of the junction:
    Bathroom Project 096sm.JPG

    In order for me to resolve the issue I would need to drill a larger hole in the joist which will violate the structual code (no hole within 2" of edge and not to exceed 1/3 of the width of the joist).

    Question is do you think this will be a major issue (with clogging) in the future or am I worrying too much?

    Thanks in advance,

    Tim
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,118
    Location:
    Bothell, Washington
    You have also altered the height of the shower drain, making is an ilegal S trap.
    I see too where you have the tub draining past the shower, which will siphon the shower trap.
    Also, you have a santee on it's side. At the least it should have been a wye fitting.

    Is any of this vented?

    So much wrong, in so little space.
    Last edited: Feb 8, 2013
  3. denikar

    denikar New Member

    Messages:
    13
    Location:
    Canton, MI
    Thanks for the reply. I guess I'm not sure how the height of the shower drain was altered as I used a complete "P" trap. Right after the "P" trap it slopes down to the T.

    I did not think about the siphoning issue - uggg :(

    As for venting yes there is one 1.5" vent in-between the shower and the tub. It is located 16" from this T and 16" from the tub drain.
  4. denikar

    denikar New Member

    Messages:
    13
    Location:
    Canton, MI
    Here is a crude sketch of the setup. Seems I have the same siphon issue with the vanity...

    Attached Files:

    Last edited: Feb 10, 2013
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,129
    Location:
    New England
    EACH trap needs its own vent...as drawn, only the tub is vented.
  6. denikar

    denikar New Member

    Messages:
    13
    Location:
    Canton, MI
    Understood and will do. Thanks for the reply.
  7. denikar

    denikar New Member

    Messages:
    13
    Location:
    Canton, MI
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,129
    Location:
    New England
    Better, but still not right! The vent line must come off the trap arm at or before it connects to the main line. The problem is, water rushing by the trap arm connection can suck the trap dry if there isn't a vent to prevent that. Just adding a vent doesn't work, it has to be in the right place as well.
  9. denikar

    denikar New Member

    Messages:
    13
    Location:
    Canton, MI
    OK I get it now I think. Thanks for the reply. Since the location of this branch is under the shower I will need to go horizontal for about 2ft to get to a place where I can go vertical:

    setup3.jpg
    Last edited: Feb 9, 2013
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,129
    Location:
    New England
    Not sure that's going to cut it either, but you're closer. COuld you run the trap arm from the shower that way, vent it, then turn and pick up the main drain line along that back wall? Or run it at a 45 towards that corner, run the vent up before joining the main line? One of the pros should comment before you tear things up, as I've probably missed something.
  11. Hammerlane

    Hammerlane Member

    Messages:
    252
    Location:
    Ohio
    The part in red cannot be horizontal at the position you show it. If the shower drain in green ever clogged up, that horizontal section of the vent could get clogged with no way of unclogging the vent.


    You cannot turn the vent horizontal until it is a certain height above the flood level rim of fixtures in that group. Someone else should chime in with specifics.

    Attached Files:

  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,811
    Location:
    Cave Creek, Arizona
    quote; Right after the "P" trap it slopes down to the T.

    That is the problem, it cannot "slope down" using those 1/16 bend fittings until AFTER the vent connection and the vent connection cannot be "horizontal" until it is 6" above the spill level of the fixture. You also cannot use a sanitary tee in a horizontal line. The installation might be better if you had designed a better routing BEFORE you started drilling holes.
  13. denikar

    denikar New Member

    Messages:
    13
    Location:
    Canton, MI
    Yes I realize I screwed up. But I want to fix it. The joists can be sistered rather easily as I've already sistered 4 of them to meet the tub loading requirements and to meet the ceramic tile maximum allowed bend requirements.

    Here is what I can do (from Jim's suggestion):
    vent idea3.jpg

    Can a vent connect to a line at a 45 degree vertical angle as shown?
  14. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,249
    Location:
    Land of Cheese
    The vent needs to be as vertical as possible, and in no case lower than 45 degrees.
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