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Thread: Need help/advice planning new plumbing for a laundry room

  1. #1
    DIY Member benze's Avatar
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    Default Need help/advice planning new DWV for a laundry room

    Hi,

    I'm adding a laundry room to my finished basement, and need some help/advice planning for the drains before I start breaking my slab.

    My planned space is roughly 88" x 61"; I know - a tight squeeze for a laundry room. I'm planning to put washer/ dryer on one wall of the room, sink on the opposite wall, and a 30" door in the middle.

    I can relatively easily plumb a 4" main drain into the room under the washer. I am thinking that it would make for a good place to put a BWV as I can easily hide the access panel under the washer.

    I was also thinking a floor drain in the middle of the room would make sense as well, being a laundry room and all.

    My question / issue is that I am not sure how to run all the lines safely and to code. From what I understand, I need a wet primer for the floor drain. Am I allowed to put the 3 fixtures (floor drain, sink and washer) all behind the BWV? If so, I assume that the sink/washer would act as the wet primer for the floor drain. However, can the washer foam out the floor drain due to the extra pressure it needs to clear the BWV? If I am allowed, what is the best way to run the required drain lines coming from the 4" BWV?

    I've attached a pic to give you a better idea of the space layout, and my initial idea for the BWV placement. BTW, the BWV inlet would be about 9-8" below the slab at this point.

    Can anyone direct me to some literature/info that would help me with this type of plumbing?

    Thanks!

    Eric
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    Last edited by benze; 08-06-2010 at 09:32 AM. Reason: Added pic and explanation

  2. #2
    DIY Member benze's Avatar
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    I've tried to sketch out what I think would make sense for plumbing, but I have no idea if this is appropriate or not. I realize that I have no vent in this room, so was considering using a SureVent under the sink. My logic being that it would vent the washer pipe at the same time since it is "above".

    Is this type of layout allowed / legal? The large 4" leaving the room ties into the main 4" running under my slab just outside my bathroom and just before the BWV that protects the bathroom fixtures (hence the desire for another BWV in this room).

    If this generally okay, does it matter that the floor drain doesn't have its own vent?

    Thanks,

    Eric
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  3. #3
    Master Plumber-Gas Fitter shacko's Avatar
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    >>>My question / issue is that I am not sure how to run all the lines safely and to code. From what I understand, I need a wet primer for the floor drain. Am I allowed to put the 3 fixtures (floor drain, sink and washer) all behind the BWV? If so, I assume that the sink/washer would act as the wet primer for the floor drain.<<<

    You can put your fixtures behind the BWV, the only way that the fixtures would prime your floor drain is if you ran your lines backwards; you need a trap primer on there.

    You need a vent ( not a sure vent ) from your sink to your wash machine hook-up and tied into a vent stack or stack vent, without venting there is a good chance that your wash machine hook-up will not drain correctly.

    Wash machine hook-up should be 2in. with a stand pipe 18-30in above the trap

    When you get your trap for you floor drain get one that is tapped for a primer hook-up, then run a piece of pex or soft copper near the drain of your sink, when you hook up your sink you can tie it into the drain, that will keep a water seal in your floor drain.

  4. #4
    DIY Member benze's Avatar
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    Thanks for the reply. My problem is that I don't have a real vent anywhere near there. When renovating my kitchen last year, I noticed that my bathroom & ktichen vent pipe was dead ended in the attic and completely clogged with insulation. At the time, my plumber recommended just removing it and putting in an AAV (Oatey SureVent to be precise) under the kitchen sink to vent the kitchen sink and the bathroom below. So far, it has been perfectly functional. After reading up as much as I have in the last few days for my laundry project, I wonder if that is to code, but I'll let the next set of home owners worry about that.

    In the meantime, even if I were to somehow plumb these lines to my bathroom vent line, it would still be to the SureVent in my ktichen. And my temporary washer hookup in the basement is functioning using a SureVent knock-off.

    After reading a little more, I realized that my idea of floor vent priming was incorrect and had to be done differently. I'm not quite sure I understand how to hook it up into the sink drain, though. Plus, I recall reading somewhere that using another drain as a source for priming was illegal as it could be used as a secondary drain path in case the sink's drain ever got clogged. Is that incorrect?

    If I were to put in 2 SureVents (one for the sink, one for the washer), would that not be functional? (see attached picture - I've drawn the AAV's in grey).

    Is there a maximum height for the washer ptrap off the floor, or does that not matter as long as the stand pipe is 18-30" above the trap?

    Additionally, do I need cleanouts anywhere along the path? And is there a maximum turn I can put between the "wye"s and the line under the slab to the sink or the washer?

    Thanks,

    Eric
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  5. #5
    Moderator & Master Plumber hj's Avatar
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    Unless you do periodic maintenance on the BWV, which NO ONE does, it will be fouled with lint from the washer and would not work when, or if, you needed it anyway. As for your piping, I might not even do it that way in the first place, but HOW I would do it would only be decided AFTER I saw your entire area. In fact, I might even recommend that the sink, washer, and dryer go side by side on the "back wall". They would only need 84", and you seem to have more than that.

  6. #6
    DIY Member benze's Avatar
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    Is there a better solution than a BWV where a washing machine is concerned? I've taken another picture to show you the overall layout, but there isn't much else to see. I'm attaching another picture to show the overall space. The main drain is drawn out in white and there is just another couple of 1st and 2nd floor drains that tie in about 15' off the right side of the picture. The box in the floor is the current BWV that protects the bathroom that needs to be replaced. I was thinking / planning on tieing in the drain for the laundry room just before that BWV to avoid having to break up much more of the floor.

    I considered putting the washer / dryer on the back wall, but then I would need to put the sink back there as well, and have no counter space. And with the new front load washer/dryers, I can't put anything on the wall in front of them or they won't open. By putting washer/dryer on one side and sink/counter on the other, I get storage space, sink, counter on one side of the room, and washer/dryer on the other. Prob not the optimal solution, but given the space constraints, I think it is the best possible outcome for the space.

    Of course, am always open to other suggestions for arrangement and plumbing.


    Thanks,

    Eric
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    Last edited by benze; 08-06-2010 at 03:40 PM.

  7. #7
    DIY Member benze's Avatar
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    After some more thought and reading up more on floor drains, I was thinking that it might make more sense to have my sink as the first fixture in the drain to act as a wet vent for the floor drain and the standpipe as well. I've modified the proposed layout. Grey still represents the AAVs.

    Questions with this layout:
    1) Am I allowed to put 2 x 45deg to create a 90deg bend in the 4" under the slab?
    2) Am I obliged to have cleanouts either at the sink or at the laundry standpipe?

    I'm really looking forward to starting this project and hoping to get all this figured out before I start breaking the slab.

    Thanks,

    Eric
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  8. #8
    DIY Member benze's Avatar
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    Default Confused by venting

    Ok - I'm a little confused here with vents. I had a plumber drop by the other day to look at what I wanted to do, and he suggested that I didn't need a vent at the sink; that one at the laundry standpipe was enough. I had assumed that one at the highest point in the slope (ie: the sink since it would be the first drain) would be the one that would for sure need a vent, and that could in theory wet vent the others. But I was told the opposite; that one at the standpipe was enough to vent the floor and the sink as well.

    Can anyone clarify this please?

    Thanks,

    Eric

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