Single to double vanity - better way? Illinois

[john-ee]

Hi,

Thanks for the great forum and advice. I'm looking to move some supply lines to transition from a single to a double vanity. The picture below is self-explanatory about what I'm thinking and I'd appreciate some experienced input to validate my plan. The drain used to be in the center of the existing supplies and I've already reconfigured it for the dual sinks with the added vent line. There is a 28" run from the left 1-1/2" drain to the center vent so I think I'm OK in that regard. I saw Terry's double vanity example picture with the black PVC drains and started down that route but I hit a snag when I realized that I didn't have quite enough space for everything to fit comfortably when overlapping the 1/2" supplies. There's only enough room for one supply in front and one supply behind the PVC. I then wanted to just move the tees below and create two new lines off of the 3/4" below, but the finished ceiling, the duct work, and the beam make that harder than I'd like. Does what I propose look unprofessional and if so, could you help me with something that works better?

Thanks,
-John-

[Terry]

No plumbing inspector would pass that setup.

Normally a plumber would use a double fixture fitting on a double lav, this way both lavs would be vented.

[wallskev]

Terry:
Would it be better to give a short reason why, other then a statement such as "No plumbing inspector would pass that setup."..

This person nees to know "WHY" and if possible, like he stated " .....and if so, could you help me with something that works better ..."

[hj]

"No inspector would approve that setup", period. The only sink "vented" is the left one. The left sink flows past the right one negating the effect of the vent on that trap. As far as the water piping is concerned, your drawing will work, although it seems to be much more complex than necessary.

[Cass]

You weren't thinking about it you did it...it's all cut and glued up....we don't know what state and or city you live in so we would have no idea what would pass and what wouldn't....

[hj]

Pass/fail depends on the code, and some of them are very lenient when it comes to hydraulic issues.

[Peter Griffin]

Besides the vent issue, how many fixtures are on those 1/2" lines?

[RTAPlumbing]

it would probably pass where i live if the arm was 2'' pipe. your tee for your vent should be the other way

[john-ee]

Thanks for all of the replies.

The drain is glued and done, but I'm certainly not opposed to cutting out a few dollars worth of fittings to do it right. I'll use a double fixture tee and run the vent vertical to above the flood-level of the vanity and tie into the existing 2" vent on the right.

Would running the centered drain from the two sinks back to the right to the existing drain be alright? I'd like to avoid cutting into the 3" drain in the basement. Since this 3" drain is pretty unmovable, getting a fitting inserted sounds somewhat difficult.

The current 1/2" supply lines are fed from two 3/4" lines running left to right in the picture. They continue on to the right for about a foot past what you see where they tee to the shower and tub toward the bottom of the picture and to the right for the toilet and a currently unused laundry hookup. The cold is 3/4" in all directions but the hot is 3/4" to the tee then 1/2" off of that.

Thanks again,
-John-

[Terry]

wallskev, At 12:30 in the morning I'm not going to give a full reason. Especially when he has seen the right way to have done this.
Which, by the way he could still do.
The fixture cross would have been closer to the right.
You can go 42" with each trap arm.

I have a second option below that would pass inspection with the 2" waste line coming up from the floor. As long as that wasn't a vent for downstairs.
The tee for the first lav would be above the first tee, and then a tee at 42" to revent the second lav.

[john-ee]

Thanks Terry. I'm going to redo it with the fixture fitting and run the drain over to the 2" line to the right, unless that creates a problem as well. The tee on that line was already there for the original vanity drain and this serves as the water closet vent as well. Nothing else below.

Thanks,
-John-

[Doherty Plumbing]

You shoulda just circuit vented the two sinks. Woulda been quick and easy.

Yes I would make the main line a min of 2" however up here that line would just have to be sized as a wet vent and it would techinically be ok on 1.5".
Plumbing in Canada

[Terry]

Here's another take on converting a single lav to a double lav

[hj]

Without a ruler in the picture, it is just a guess, but given the distance of the horizontal vent above the openings for the sink drains, I am guessing that it is neither 42" above the floor, NOR 6" above the sink rims.

[xr4ti]

Without a ruler in the picture, it is just a guess, but given the distance of the horizontal vent above the openings for the sink drains, I am guessing that it is neither 42" above the floor, NOR 6" above the sink rims.

Double vanity at a child daycare?