I have a two story home with an upstairs toilet. It has a 2" vent line within critical distance. Currently this vent comes up a wall and then into a attic space where it continues upward (at roof pitch) and terminates into a 3" roof vent about 10-12 feet vertical and approximately 20 feet away from the toilet.

I am wanting to eliminate this roof through hole and tie this toilet vent into another 3" stack exiting the roof about 10 feet further away, but would have to change vent elevation to get there. I believe I am fine on fixture count for this vent (3 baths, one kitchen, laundry) but my concern is to tie into this stack, the existing 2" vent line would have to angle down about 2-3 feet then run horizontally 10 foot over to the stack.

So it would look like this:

2" vent pipe within critical distance from toilet. Travels vertically up 8 foot wall into attic space. Continues at roof pitch angle (7/12) within attic for about about 20 feet (where now it joins a small stub of vertical 3" to exit roof). Cut at transition to existing roof exit and add 45 degree fitting angling back down for about 2-3 feet. This angle would end up at about 25-30 degrees. 90 degree fitting turning on a horizontal plane towards main stack vent, then travel another 8 feet horizontally joining into main stack. All this would take place at heights within the attic of 11-12 feet above toilet drain.

I hope that makes sense. Moisture (rain, condensation etc.) would be able to drain either side of the 45 towards toilet or towards main stack. This is all somewhat tempered space... with HVAC supply lines traversing.

I know vents should always angle towards fixture... will this work? I am going to check with the local inspector... but thought someone here might have a definitive Yes/No before hand.

Thanks,