: Im moving my tub 8 away from its present stack/vent with only a 9 1/4 joist space to run the drain line. To vent this should I wye in just beyond the trap and run another parallel line above the drain line over to the vent stack? Using 1 1/2 waste line, does the vent line also have to be 1 1/2 or will 1 suffice?Your vent only has to be within 5ft of the p-trap and can connect anywhere above the horizontal plan on the drain piping itself. Any vent size is better than non at all but a 11/2 would be best suited.
