Does a vent always have to run uphill?
I'm trying to move a sink. Moving the drain is easy since the basement is unfinished but to reroute the vent I'll have to notch a half dozen load bearing 2x4 studs or come up with another idea.
What if I ran the sink vent up (6"+ above the rim of the sink basin), turned around, back down the wall, under the floor, and then connected to the old vent stack?
In concept, this should work fine. There will be air admitted into the drain just downstream of the trap. It will have to draw the air up a few feet but that shouldn't matter. No water will ever get into the vent.
Any thoughts?