Add bathtub - second floor remodel

[beniciaDIY]

Looking to add bathtub in second floor remodel. I have access to 1.5 inch horizontal shower drain line (approx. 4 ft from proposed bathtub drain) in the floor that empties into 2" vertical drain in the wall (approx. 7 ft from proposed tube drain), the main soil stack is also in the wall on this side of the bathroom. On the opposite side of the bathroom, I have a vertical 1.5 inch line, what I assume is a vent line from the downstairs bath that exits separately from the main stack through the roof in the opposite wall (approx. 2 ft from the proposed new tube drain).

My question is to which line do I connect the new bathtub drain? Can I drain and vent to the closest vent line from downstairs? Can I wye into the existing shower drain and use the closer vent pipe to vent? Or do I need to drain to the vertical pipe above or below the shower line and vent to the closer vent pipe? None of the above?

 

[hj]

You CANNOT connect to the downstairs vent, and SHOULD not connect to the shower drain line. You CAN connect to the vertical drain line, if you do it correctly.

 

[Sponsor]

 

[beniciaDIY]

hj,

Thanks. Figured it had to be the hardest option. As the horizontal run is close to 7 ft ad I need 1/4 inch per ft slope, I assume I cannot use the 2 inch vertical that the shower is using and have to tie into the 3 inch soil stack?