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