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Can I rough plumb a double vanity like this?

Javelin
Javelin Member Posts: 147

Many have been so helpful with my bigger discussion on my master bath plumbing, but now a quick question.. didn't want to bury it in the other thread since it can stand alone…

I have a need to put the main drain of a double vanity TOWARD (but not close enough to freeze or anything) an exterior wall. Could I plumb it similar to attached? I'd add a clean out JIC as the line still goes under the floor for about 7 feet before it ties into the 4" main stack.

Can I plumb it like this rather than the traditional double waste T? These are 1.5" PVC waste/vents to be clear.

THANK YOU!


Mad Dog_2

Comments

  • HVACNUT
    HVACNUT Member Posts: 6,466

    I don't do plumbing, so I don't understand the connected loop on the left side. Can't the top and bottom tee's for the left hand sink just be 90° els?

    And I think the TY on the main vent is upside down.

  • kcopp
    kcopp Member Posts: 4,489

    Venting needs to be 6" above the flood rim level before going horizontal.

    I also dont get the 90s on the ends…

    Yes the Tee Wye on the vent is upside down.

    Mad Dog_2
  • Kaos
    Kaos Member Posts: 356

    That loops on the ends are not needed. Raise the vent above flood rim and just run it up, it doesn't need to connect to the drain on the wall side.

  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,628

    As the guys said.

    1. Bottom.of vent header needs to be a minimum of 6" Bove the Flood level rim of the fixtures.
    2. You need to dump waste in to a wye & 1/8th bend or a Long Turn Tee Wye. Sanitary Tees (Tee wyes) not code or good practice.
    3. The Circuit type venting you show is how we pipe commercial jobs. That's the way I would do it. Mad Dog

  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,628

    You don't "need" the last loop vented portion, but I like the additional circulation and an accessible Clean out plug to hit the common waste run. Mad Dog

  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,628

    This is nice too and less piping & drilling. Mad Dog

  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,628

    Forgot the Cleanout on right lav...They are a Godsend when you've done alot of sewer & drain cleaning. Mad Dog

  • Javelin
    Javelin Member Posts: 147

    Thank you all so much for your expert advice! I've reworked the model with:

    1. Colors - white is 1.5", light aqua is 2" with 1.5" inlets, dark aqua is 2"
    2. I made the waste dump a long turn
    3. added suggested clean outs above san-tees…
    4. Reverse the vent Tee Wye
    5. I put a sink in for reference - NOT in proper position. In reality, we're probably going to do a double console sink.. so not even sure the cleanouts will be easily accessible without taking off a counter or something, but still, might as well add them now..right?

    How we lookin' ?

  • MikeL_2
    MikeL_2 Member Posts: 518
    edited 5:11PM

    One of my favorite subjects & discussions is dwv system piping.

    I propose a single 1.5" waste arm could serve both lavs as long as they're within 6' of the stack vent.

    The arm would connect to the stack with a ty; a vertical wye with a 45 here could cause the vent to be flooded.

    The first lav would need a horizontal wye & 45.

    This works as a combination waste & vent, not a wet vent because the 1.5" arm is a pipe size bigger than the lavs 1.25" drain....…

    DCContrarian
  • Lance
    Lance Member Posts: 318

    Its all in the code. Follow the code, pass the inspection. This is the reason masters have to learn their trade. Get the illustrated national code book and its all there. You may think logic and reason works, but its all physics. The vent opening above the roof in freezing areas has to be large enough to prevent frost closure. They used to be small until nature told them how to it must be to work right. Just one example to not ignore the codes. By the way, people do die when plumbers fail to do it right. Especially with cross connections. But isn't that true in all trades? Many do not appreciate good craftsman who save lives by preventing hazards.

  • Intplm.
    Intplm. Member Posts: 2,325

    Looks better.

    "The waste dump" .Are you referring to the fitting that transitions from horizontal to vertical in aqua? If so then that fitting should be a tee-wye.

    If this is going to be a vanity lav set up, then you can expose the clean out plug through the wall there. If it is a pedestal lavatory not so much, unless you redirect the plug to an accessible area, and maybe decoratively through the wall, and then make it readily accessible in the wall.

  • DCContrarian
    DCContrarian Member Posts: 834

    This would be my vote as well. Much simpler. From the picture it looks like the far sink is less than three stud bays from the stack, well within reach of a 1-1/2" trap arm.

  • DCContrarian
    DCContrarian Member Posts: 834

    And I don't see any point in the clean outs, just use a trap that comes apart and go in there if you need to.

    MikeL_2
  • Javelin
    Javelin Member Posts: 147
    edited 3:27PM

    Thank you again.. a couple of points of clarity…

    1. the 1.5" vent there will go up into a soffit in the ceiling, turn 90, then go about 9 ft until it ties into another 1.5" (from the shower), then up to the attic where they tie into a 4" main vent. Not sure if that matters to this discussion.
    2. So I still seem confused on which fitting to dump the 2" horizontal into the 2" vertical.. please see the fitting highlighted in orange… Then reference the 3 "floating" fittings in the foreground… 1, 2, 3.. .which should I use?
    3. And not knowing any better, I sort of agree with the clean out comment from @DCContrarian maybe? I don't think I will easily be able to get to them, and can always "slip out" the trap under each sink if really needed right?

  • hot_rod
    hot_rod Member Posts: 23,849

    can you get below to come up between the two lavs?

    Is the vertical pipe you show venting a fixture below? If so you cannot dump into it.

    A CO is required to be the full size of the piping. If the sinks have 1-1/4" traps, they do not serve as a CO, technically speaking.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Intplm.
    Intplm. Member Posts: 2,325

    @Javelin As far as installing a clean out . If you are installing a vanity lavatory in your bathroom and not a pedestal lav. as you have pictured, then a clean out is very easy to install. Just install it with a wye, with the plug on the branch or the run and then install the trap.

    We have been installing them for a few years now. It helps very much with drain cleaning and is a better access point for rodding. In some areas doing this has become plumbing code. We have even installed clean outs on a vent when practical.

    To eliminate the confusion about your drain piping.

    Horizontal to vertical… A tee wye. So the orange fitting should be (number three.)

    Vertical to horizontal… A wye and 45deg. or the Combo that you have pictured (number two.) Which means the lav drain second from the left needs a wye and 45deg. or the combo and not a sanitary tee wye.

    You might want to pick up a book that shows the different types of DWV (drainage waist and vent) fittings and pipe. This will help to learn what they are called and what they are used for. If you don't do that little bit of homework, I'm afraid I might further confuse you and I don't want to do that. 😋

  • hot_rod
    hot_rod Member Posts: 23,849

    Another option is a clean out tee. You can get a cover that screws to the plug also. These will usually fit in a 2x4 wall to easily cover them.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • mattmia2
    mattmia2 Member Posts: 11,175

    The plumbing code and residential code are now online. You can read them online.

    If you use a plain tee for the cleanout you can go down in to the waste or up in to the vent from it.