Krow
Plumber
Considering there's no wall available between the drain and the stack going down to the basement, how is it possible to vent in this scenario? Consider a drain that goes down to the basement 3 feet away, but is in the middle of a room, how can you vent this?
What you have to do is raise the vent as high as you can above the horizontal plane of the drain and go to the nearest wall possible and come up at your 6" above your fixture. Code in Ontario prefers that you raise the vent immediatly, where ever possible