Vent concerns and underground basement pipes

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by stoneweed1, Jan 31, 2008.

  1. stoneweed1

    stoneweed1 New Member

    Messages:
    6
    This is my first attempt ever at installing underground pipes for a full bath in the basement and i'd like to know if:

    1) Is the shower (far right 2" pipe) properly vented?

    2) If the shower trap looks good?

    3) When I pour the 4" of concrete in the shower area to close it, whats the best way to do it? the concern is that the majority of the trap would be concreted and enveloped in that area. is this method okay or is there an alternative way?

    4) Must one reinstall a vapor barrier below the concrete once finished? i didn't install a vapor barrier in this case.

    5) Overall does it look fine? I already concreted everything up except for the shower trap area.

    So from left to right it is sink, toilet, and shower. the sink will drain into the main stack. the main stack then goes down under the concrete and sweeps to the right and connects to the 3" toilet drain approx 1 foot to the right of where toilet flange would be. This would vent the toilet and the shower. The toilet drain then continues to the right and then the shower p trap appears and drains into the 3" drain that originates from the toilet drain. The distance from the shower drain to what I presume is the vent is approx 4 feet. The graph paper diagram shows it better. Thanks in advance.

    Attached Files:

    Last edited: Jan 31, 2008
  2. prashster

    prashster New Member

    Messages:
    941
    That shower looks like an s trap to me. Where's the vent?

    You shld replace the vapor barrier under the concrete. Doesn't matter if it's under the pipes or over it.

    I'd fill most of the cavity with gravel and then put a mud or topping mix on the top 2". That'll make any future bust up a little less painful if necessary.
  3. stoneweed1

    stoneweed1 New Member

    Messages:
    6
    vent and s trap

    the vent for the shower would be the same as for the toilet. am i incorrect in assuming that this vent would work?

    is the s trap okay?
  4. prashster

    prashster New Member

    Messages:
    941
    the pros'll chime in, but if it were me, I wouldn't make an s trap. The fact that it's an S means it's not vented properly. You need a vent after the trap b4 it xitions down to avoid the S. S traps can siphon when the fixture drains.
  5. patrick88

    patrick88 Plumber

    Messages:
    836
    Location:
    Webster Ma.
    I really hate to say but you need to open the floor again. The shower needs to connect with a wye off the large drain 3"-4" what ever your using. The full "S" trap you have is a big NO NO. The drain will siphon. Your bathroom will smell really bad and your wife will kick your butt.

    You need to have trap-vent-drain.

    Good Luck
  6. stoneweed1

    stoneweed1 New Member

    Messages:
    6
    s trap and venting

    so basically I need to add a vent to the right of the shower drain and not to the left like the picture shows?

    adding a vent to the right of the shower drain would mean not reopening up the floor, but rather opening up a new area that I already haven't opened up. and this vent could just go straight to the wall and up into the vent pipe that runs along the top plate?

    and use a wye for the shower that drains into the 3" pipe and get rid of the s trap thing?

    thanks
    Last edited: Feb 1, 2008
  7. markts30

    markts30 Commercial Plumber

    Messages:
    630
    Location:
    Phoenix, AZ
    Reopen floor...
    Santee on drain is illegal where you have it... Have to replace it with a combo or wye...
    Should have used PTrap instead of sweep at shower termination...
    Vent shower properly into wall...
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,293
    Location:
    Cave Creek, Arizona
    drains

    " A little knowledge is a dangerous thing." Your toilet vent connect uses the wrong fitting and is "flat". The shower has a "S" trap and NO vent. The vent has to go between the trap and the connection to the sewer, and in your case there is probably not a good way to do it and still have a "nice" drain.
  9. stoneweed1

    stoneweed1 New Member

    Messages:
    6
    underground redo

    so is this what the redo should look like?

    toilet has Vent2 about 12 inches downstream

    shower has Vent3 about 12 inches downstream from where the p trap ties into the 3" drain.

    Attached Files:

  10. patrick88

    patrick88 Plumber

    Messages:
    836
    Location:
    Webster Ma.
    You need to pull the vent right after the trap before the main drain.

    Go trap-vent-main drain. You will need to use a 2" tee wye. You will need to place it not flat on its side but atleast slightly turned up so water rolls back into the drainage system.
  11. stoneweed1

    stoneweed1 New Member

    Messages:
    6
    redo pics

    i have two redos

    one that has the shower with a p trap that goes to the left and is vented before it ties into the 3" pipe.

    the other is where both the toilet and the shower go to the left and tie into the 3" main stack and then out to the sewer.

    any thoughts of which is better?

    thanks again

    Attached Files:

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