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-   -   Basement floor drain and vent (https://www.askmehelpdesk.com/showthread.php?t=539668)

  • Jan 1, 2011, 06:59 PM
    thelastlaugh
    1 Attachment(s)
    Basement floor drain and vent
    I'm adding a laundry room to my basement and need some help regarding putting in a floor drain.

    I've attached a picture of what I was considering doing, but I'm having a hard time believing it would be that easy.

    1. Do I have to have a floor drain? Is there an alternative?
    2. Does the floor drain need a separate vent?
    3. Is a 2" pipe adequate?
    4. Is a P-Trap necessary? What about a primer(?) valve?
  • Jan 1, 2011, 08:50 PM
    massplumber2008

    Hi to you thelastlaugh...

    See my post below.

    Mark
  • Jan 2, 2011, 02:05 PM
    thelastlaugh
    Comment on massplumber2008's post
    No hurries here -- been working on the basement for months so a couple more days aren't going to affect me. Thank you.
  • Jan 2, 2011, 03:55 PM
    massplumber2008

    Hi TLL...

    1) Code does not require a floor drain to be installed in a laundry room or anywhere on a residential property for that matter. A floor drain is certainly ideal, however, but if the floor isn't properly pitched to the floor drain it's hard to say where the water will go anyway... ;)

    Alternatives include things like FLOODSTOP automatic shutoff and a washing machine pan. Here, the washer is placed into a washing machine pan and the floodstop shutoff is connected to the water supply feeding the washer and then a sensor from the floodstop shutoff is placed into the pan and if the sensor senses water at any time then the floodstop shutoff automatically stops water flow to the machine.

    2) If you plan on hooking the floor drain to the washing machine drain piping then YES, the floor drain will require a separate 1.5" vent. Here, the washing machine puts out such a great volume of water at such a great velocity if the floor dain isn't vented the floor drain PTRAP could easily be siphoned of its water and that would allow sewer gasses into your home...a definite no-no!

    3) A 2" PTRAP is the proper size for a floor drain.

    4) If you install the floor drain you'll definitely need the PTRAP (as well as vent mentioned above). ALL fixtures, including floor drains need the PTRAP to keep seweer gasses from coming into your home.

    A trap primer would also be required by codes in my area. Otherwise, you'll need to plan on pouring water into the floor drain on a regular basis. There are a couple other alternatives to the trap primer, but they are not code legal so I won't go into them unless you want me to, OK?

    Finally, if you connect the floor drain into the washing machine drain then connect the floor drain into the drain using a WYE fitting. You can use a sanitary tee to connect the vent into the floor drain drain pipe.

    The tub vent and the floor drain vent must connect into the washing machine vent a minimum of 42" off the finish floor. Here, all vents on a floor must connect at least 6 inches above the flood level rim of the highest fixture on the floor...in this case, the bathroom sink is most common at about 34" or so and add 6" above that gives you about 40" off the floor. For the sake of argument we generalize to 42"-48" range off the finish floor. The vent fittings must also be INVERTED where they connect into the washing machine vent, i.e. the tee fitting must be turned upside down.

    Back to you...

    Mark
  • Jan 4, 2011, 09:11 PM
    thelastlaugh
    Hello Mark,
    Thank you very much for the clear and concise explanation. Looks like it's going to take me a little longer to get done :rolleyes:

    So assuming I decide to do the floor drain instead of the pan
    1. Can I use 1 1/2" for the whole vent line?
    2. Is there a min/max distance from the trap required to attach the vent line?
    3. Instead of attaching it to the washing machine vent vertically, can I take it straight up the side and tee it in at the very top, horizontally?

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