Vent Problem

OK, here is my diagram.

The issue is the 2nd floor section of the green main vent pipe.

This thing is 4" cast iron. It comes out from the basement wall, connects to all of the house plumbing (kitchen and bath) and then goes strait up thru the roof.

The problem: It sits 4 feet off of one wall and 1 foot off another wall in my master bedroom (used to be attic space).

I need to find out what my options are for rerouting this thing.

Does it have to be 4" all the way up and if not, what is the minimum size? Can I put 90s in it since it is a vent? Can I yank the whole thing from just above the toilet connection and replace with PVC?

I am located in Portland, OR, Multnomah County.

Thanks
Holly

Codes vary. Some require one full size vent all the way to the roof, but I suspect you could at least reduce this to 3"/ It cannot go horizontal below a point 42" above the second floor (or 6" above the flood rim of the second floor sink, which may work out to be around 38 to 40")

vent

If your drawing is exact and that vent has no connections to it between the first floor and the roof, then you may have several options, depending on your code's requirements. It only has to be 42" or 6", (whichever i is higher), above the flood rim on an ATTACHED fixture. so you can offset it almost anywhere between that point on the first floor and the roof. Codes will determine whether you can reduce its size. If you can reduce it, then the amount of reduction may depend on how many other vents are going out through the roof.

In my town, you CAN replace the offending section with a different material (PVC) with a flexible rubber hub. If it's behind the wall, my inspector requires even vents to have full metal sleeves on the flexible couplings.

Also, my town permits twisting and turning the vent using 90's as long as slope (I kept > 1/4") back to the drain is maintained. Don't want to have condensation - and there will be condensation - collecting in any valleys.

If you ARE permitted to move the roof penetration to a more tasteful location, good luck sealing the old hole adequately.

hj said:

If your drawing is exact and that vent has no connections to it between the first floor and the roof, then you may have several options, depending on your code's requirements. It only has to be 42" or 6", (whichever i is higher), above the flood rim on an ATTACHED fixture. so you can offset it almost anywhere between that point on the first floor and the roof. Codes will determine whether you can reduce its size. If you can reduce it, then the amount of reduction may depend on how many other vents are going out through the roof.

Click to expand...

It is correct, there are no connections to it from the first floor up. I was advised previously (on this forum) that I cannot hook the second floor proposed bathroom into it as it would no longer be a vent for the first floor. That is why the second floor bathroom now has it's own drop down to the basement level and it's own vent.

I would want to take the existing vent 1ft North into the exterior wall or 4ft West into the same wall the new bathroom vent will be going up. I believe that I have enough room between the first floor ceiling and the second floor floor to account for the 1/4" slope needed.

Thanks for the advise. I will double check with a local plumber or inspector before I cut this monster out.