View Full Version : Will this idea work for double vanity drain?
08-13-2008, 12:36 PM
Long time lurker, first time poster. I would like to install two vanities along a long wall which previously had one single sink right in the center. The supply lines are not an issue but the drain is because it drops down into a concrete slab foundation. So what I would like to do is install a 90-degree fitting on the existing stub out (shorten the stub first, of course) facing left and put a second sanitary tee above or below the one for existing stub out, then use another 90 degree fitting taking that pipe to the right. Then 90-degree fittings at the end of each new run (about 24") to exit the wall. Hope this makes sense! I then planned to use 2x2" lumber to fir out the wall to 2x6 dimension with voids for the new drain pipe to pass through. Am I crazy? Any other ideas? Thanks in advance for your help.
Master Plumber 101
08-13-2008, 01:07 PM
Mr. Cable W,
I think I might of followed what you said but not totally sure. Cut the exsisting connection off and start fresh. You should use a double wye in this instance. Confirm the size of the pipe penetrating through the slap(most likely 2" per code underground.) Purchase a 2x1/1/2 double wye, 2- 1/1/2 street 45's and a 2x1/1/2 flush bushing if the vent required is 1/1/2. You may need to attach to existing with a fernco or clamp all. Set the center of the drains after double wye is assembled at 17 1/2". By the time you get to your location on both sides you should be at 18" to center of stub out. Rough waters at 21" and you are golden. SWEEEEEEEEET! I forgot get to regular sweep 90's for your stub outs.Good Luck Chuck!
08-13-2008, 01:29 PM
You understood perfectly. Thanks for the advice. I guess what I am trying to determine is if the drain pipe going into the slab is 2" which I think it is (I am not at home right now), that will be too big to run inside 2x4 studs, right? Maybe there is a 2" double sanitary tee with 1-1/2" inlets? That would allow me to make comfortable size holes within the existing studs. This is all schedule 40 by the way.
Master Plumber 101
08-13-2008, 01:36 PM
It would be wise to use a double wye, remember the only thing 2" is going to be the vertical section of pipe and the vertical section of the wye. The branches going to your lavs are still going to remain 1/1/2. Hope that helps.