2nd Floor Primary Bathroom Renovation: Tub Drain & Vent

[mrboardboy]

We removed the original jetted (& enclosed) tub only to find the 1 1/2" drain vent jogs out of the wall and thru the floor and connects to the 2" drain line. We would like to redirect the vent thru the plate and below the floor, turn 90° thru the adjacent floor joist then another 90° and re-connect to the end of the 2" drain line.

Our new tub has a center drain (tip of red pen, lower center) with a proposed route that would connect to the 2" drain line thru a reducing wye about 8" downstream of the vent connection. The double lav drain is vented separately and joins the 2" main about 5' from 1/4 turn. About 8' further the 2" drain connects to a 3" vertical drain.

The entire tub area is cantilevered left of the 2x6 stud visible in the photo.

I have also included a 3D model of both existing and proposed drain systems for reference.

It is physically doable, but is it code worthy?

Thanks in advance.

 

[Nillobves]

I ran into something similar during my own upstairs reno—routing the vent was tricky with those floor joists. I had to offset the drain slightly and go with a low-profile trap. Once the plumbing was sorted, I finished the base with skirting boards from mdfskirtingworld.co.uk because they had a size that worked well to hide everything without raising the whole floor unnecessarily.