Plumbing Sinks

Both sinks plumbing goes through the floor and all the things I see online are the facilities that go through the floor. The AAV has to step over the trap and about the pipe that protrudes through the plant is 1 1/4 pipe coming out of the bottom of the s trap. Can I cut the tube down and run the 1 1/2 pvc top so you can connect a trap star and go from that to add the aav? Please help ASAP. I have only one vent stack for all my plumbing and everything slow drains. Thank you. Well, I have the answer. There are plenty of ways to install a vent Studor, but s-traps are no longer legal in many states, not to say they do not work, but there are plenty of other options