In Wall Horizontal Pipe Runs

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by jasonal119, Jan 24, 2010.

  1. jasonal119

    jasonal119 New Member

    Messages:
    6
    Location:
    OFallon, MO
    I am in the process of finishing my basement and have a strange question. When you are running pipe horizontally within the walls (notched or through holes) which pipe runs above the other? Is the hot pipe on the top or the bottom?

    Also another (similar question)... in this basement I have an existing stack which was installed during construction for the half bathroom. The builder placed a saniary tee at the height for a sink drain and then capped it off. This stack sits between the bathroom and where a wet bar will be. I want to use that stack (2" stack w/ 1 1/2" stub) to drain both of the sinks. Can I run the pipes between the two sinks with another tee in the middle and connect the combined waste into the existing san tee? The sinks would both be in 1 1/2" PVC.

    Thanks for the help!

    Jason
  2. krow

    krow Plumber

    Messages:
    906
    Location:
    Ontario, Canada
    There isn't any code that says which water pipe should be on top or the bottom. Good plumbing practice is to run both pipes as to not cross them. In other words, where ever possible, do not cross one pipe in front of the other.

    Your second question is =no
    Each fixture should be individually vented and separately trapped
  3. Terry

    Terry Administrator Staff Member

    Messages:
    14,999
    Location:
    Bothell, Washington
    Most plumbers run hot high and cold low.
    It's not code, but it's common.
  4. jasonal119

    jasonal119 New Member

    Messages:
    6
    Location:
    OFallon, MO
    Thank you all for your help... Is there a "standard" for the height of the pipes in the wall? (The actual runs, not the connections for the fixtures which do have a typical height)

    Jason
  5. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Shortest route possible.

    You're over thinking this.
  6. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    If you go with pex you can just throw it any witch way and no one will care ;)
  7. Lightwave

    Lightwave New Member

    Messages:
    98
    Location:
    Vancouver, BC
    Don't place them 14" from the floor unless you're sure you're never going to put an electrical outlet in the wall.

    Don't place them 48" from the floor unless you're sure you're never going to put a light switch in the wall.

    Keep hot and cold pipes far enough apart that they can be insulated separately.

    Insulate all supply pipes that run above wiring or electrical boxes.

    Avoid running pipes in outside walls above frost depth unless you have no other option.
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,614
    Location:
    Cave Creek, Arizona
    IN the "old days" when piping was exposed, we ran the cold on top so that if someone leaned on them they would not get burned by the hot water pipe. WHat you want to do is possible, but the real factor is HOW you do it. That would determine whether it was correct or not.
  9. Terry

    Terry Administrator Staff Member

    Messages:
    14,999
    Location:
    Bothell, Washington
    Pipes not in walls?
    Okay, was that before they moved toilets inside?

    Okay, I guess when I go into Seattle and see the old galvanzed pipes hanging in the basements you would worry about people leaning on the pipes.
    I started off when copper was in vogue.
    And we drilled studs and nail plated.

    I was glad I didn't have to thread pipe all day, though I did do a bit of gas piping.

    If I'm picket fencing the pipes, I set a 2x4 on the bottom stud with the 3.5" high side up and mark the studs.
    This way I could just throw a tee in for the water closet. (toilet)
    I then mark the top holes so it clears the lav stub out.
    But really, anywhere in the wall will work.
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