Back to back sink drains

[Jeff H Young]

Used to rough in a lav at 18 back when counters in bathroom were 30 inch high I was doing 22 if they were high counters and they were always plenty low enough.
12 or 13 was my kitchens and these were guesses I kinda hate the p trap so low but damned if I'm getting burned by having to bust wall open and lower the trap arm.
Today I push a little harder for answers from builder or owner on the particular info needed but we had to many jobs to be holding hands and waiting for answers

 

[Ridgerunner66]

I'm not up on the latest recommendations for sink stub out heights, I think it might be more like 18-20" for the vanity and 12"-16" for the kitchen sink. There are threads here on that.

On the dry vents, any horizontal segment needs to be 6" above the flood rim of the fixture(s), as should any joining of dry vents.

Cheers, Wayne

Thanks, Wayne, I appreciate your time and input... I set mine at 18 for the vanity.

 

[Sponsor]

 

[Ridgerunner66]

After talking to a contractor buddy who isn't a plumber, we came up with this configuration. I would like to put an air admittance valve on top of the vent to avoid going through the roof. Any thing missing or incorrect?

Thanks!

 

[Terry]

Normally going from vertical to horizontal the inspector wants a long turn 90.
That could have also been done with a wye and a 45. The less changes of direction the better, and the longer sweep going from vertical to horizontal the better.

This was a conversion of a single to a double that only had 1.5"
Two lavs by code need 2", so it would be a 2x1.5 wye at the low end there.