Need help with Vanity Plumbing

[jakester]

I am upgrading from a single sink (30" vanity) to a double sink (60" vanity) my question is how to run the plumbing the correct way? In the attached pictures you can see where the only sink was, the second sink will be to the right of that one. I need to keep the plumbing in the wall because I won't be able to run inside or underneath the vanity. Also what size pipes should I used and what size pipe should be coming out of the wall?

 

[PlumberMike]

cut the 90 out install a wye on its side with a street 45 then continue it with the next sink with a 90 all the pipes can be 1 1/2

 

[jakester]

That is what I originally thought about doing but wanted to make sure that is the correct way to do it. I am not a professional but like things done correctly.

 

[Mr_David]

That would be installing a trap for each sink with a common trap arm to vent which is an incorrect installation. Each trap should have its own vent.
Use a double fixture tee
2x1-1/2x1-1/2x1-1/2.
2” 1/4 bend out the bottom of the tee. A single vent up and back to main vent above flood rim of sink. Lower the existing santee

 

[jakester]

David - I am not sure I can picture what you wrote but my problem is the main stack is and will be to the left of both my sinks and that is what is making this challenging. If the main stack was in the middle I could have just used a double fixture tee and be done with it.

 

[jakester]

is this what you mean?

 

[jakester]

Does it look right the way I drew it in the picture above?

 

[jakester]

Can someone help me out? I just want to make sure I got this right.

 

[gagecalman]

It's fine. Tie in both vents at least 42" above the floor.

 

[jakester]

I attached some pictures. The 1st one is how it is now, picture 2 and 3 is what I was thinking about doing, what do you guys think will be better. Sorry for all of these questions, I not a plumber but I am a DIY'er but want to do it right.

 

[gagecalman]

Picture 2.
Use a double fixture tee not a double sanitary tee.
Tie in the new vent and the old vent from below at least 42" above the floor.

 

[jakester]

Is it just me or is a double fixture tee hard to find at a home depot or lowes?

 

[gagecalman]

Yes it is.
Try plumbing supply house or:
https://www.amazon.com/dp/B003O5LZP2/?tag=skimlinks_replacement-20
DWV Double Fix, 2 x 1.5 x 1.5 x 1.5-Inch. 2" at bottom.

 

[jakester]

Thank you! If anyone has any other thoughts, ideas please share.

 

[CT-18]

I would run that other vent up higher also. Should be 6" above the flood level. That way if that line ever backs up it spills over the sink and not down the vent.

 

[jakester]

you mean the vent all the way on the left?

 

[gagecalman]

Yes. See post 11.

 

[jakester]

Yea just making sure that is what he was talking about.

 

[jakester]

The part that I circled can stay correct?

 

[gagecalman]

I hope this helps.
You might want to double up the studs to accommodate the holes for the 2" pipe.
See the PDF.



View attachment Drain.pdf