Can I drain new sink and tub into what was vent line?

[ted]

This seems to be only way to gain access to drain system for new sink and tub.

Also, can I put upside down p trap in long horizontal drain line to prevent water from running both ways?

A friend said this was called a wet stack and it was ok?

 

[frodo]

no no and no

 

[ted]

Any reasons or just bsing???

 

[Mr_David]

Go up to the top of this Forum. Type in "wet vent"

I'll bet you get more posts related to this topic than you can read.

This topic has been cover so many times a few here are probably tired of talking about it.

draw a picture of what you already have, and what you propose to do.
post it. That way we can tell you with more specifics about what and why you can or can't do.