Need to install a washer. Lots of issues that make it impractical to tie into any existing vent stack system. The plumbing inspector says a new stack must be 3". That's going to mean copper rather than PVC to get it inside 2x4 stud bays.
A plumber suggests only the roof penetration needs to be 3", that the run through the wall can be 2" and transition to 3" in the space above the ceiling. Anybody with experience in Westchester County, NY want to comment?
Any concerns about the stack going up through a flat roof at a lower elevation than intersecting gables or gable ends. I plan on staying 10' away from a window in the gable end.