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.

 

[Sponsor]

 

[Wallskev]

Becasue is not a resaon why !

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]

dwv

"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]

code

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

 

[NHmaster]

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 technically 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?

 

[Terry]

I thought it looked low too.
That was a picture sent to me by someone that was installing vessel sinks.

She is having drain problems related to the small grid drains.

Yeah, must be a tiny daycare bathroom.

I believe she said the work had been done by a "Handyman".

More drywall should have been cut, and the revent 6" higher then the vessel sinks.

 

[Winslow]

I thought it looked low too.
That was a picture sent to me by someone that was installing vessel sinks.

She is having drain problems related to the small grid drains.

Yeah, must be a tiny daycare bathroom.

I believe she said the work had been done by a "Handyman".

More drywall should have been cut, and the revent 6" higher then the vessel sinks.

The way some of them grid drains are constructed the sinks won't drain properly, they drain slowly then when enough head pressure builds up it dumps. Not sure if maybe the openings in the grid don't equal the cross section of the drain as required, but Ive run into that problem before.

Regarding the the picture if the furthest sink was within 3 1/2 feet I would stack the tee's and wet vent the lower drain.

 

[Terry]

One more way.

 

[hj]

quote; Double vanity at a child daycare?

Codes do NOT make exceptions for a daycare center. What happens when it becomes an "adult facility" and the sinks are raised? That is why the code says, "42" or 6" above the sink rim, whichever is HIGHER", they are considering what COULD happen down the road, NOT what is happening now. The problem with grid stainers is that the openings are not large enough to allow the air to escape while the water is trying to flow into them. Inserting a straw into a hole or making the holes larger will permit full drain flow. The same thing happens with "rainfall" shower heads which are installed perfectly flat/horizontal. There are a lot of ways to do the drainage, depending on how much time and money he wants to use.

 

[Ken Parlee]

Hi there. I am installing a double vanity that is 49" wide in a 2nd floor bathroom. As the main stack is right above the vanity (and originally ran right through where we want to install an in-wall medicine cabinet, I rerouted the vent to the right of the vanity which changes from a 3" to a 1 1/2' pipe which I believe routes below the floor over to the toilet and shower on the other side of the bathroom. The main vent was reconnected next to that (see image 1) which becomes the wet vent to the 1st floor.

I thought I had this right and then found the info about the 6" gap between a horizontal dry vent and the top of a sink. I then found your posts and images which greatly helped me to figure out how to do the vanity vent and drains but realized I used the wrong image - the 'daycare' photo above.

I wonder if you can check my work before I cut out some sections and redo it.



Instead, I think it it should be more like Image 2. My plan is to move the orange 3" pipe up 2" to stay above the 6" limit and redirect the vent down and across using a 3 x 3 x 3 Wye. I'll convert the 3" connection to a 1 1/2" for the left sink. Thankfully this is not a load-bearing wall. I believe my right sink drain is OK.



I appreciate all the info Terry and the other pros provide. When doing a bathroom for the first time, there certainly is a lot to learn about multiple trades!

Ken in Ottawa