I think my vent stack is plugged; I think this because the toilets sound different while flushing than I think they should, and I hear a knocking in the wall when a sink or toilet is flushed. Normally I would go up on the roof and look in the vent stack, but my roof has a steep angle and is not walkable. I realize I could use roof jacks, but I'm hoping I can avoid it.
What I would like to do is go into the attic where there is plenty of room to work and cut the vent stack into two halves so I can look in it that way (The vent stack is PVC). After checking for blocks and fixing if necessary, I would re-attach the stack with a rubber coupling meant for PVC pipe, or if that's discouraged, weld a PVC coupling to re-attach the two halves.
Would my idea be acceptable? I can't see any functional problem with it, but I'm wondering what an inspector might think years down the line, or if it's against code.
Best Answer
I'd suggest cutting out enough pipe to insert a cleanout tee & threaded plug, either "instead of a coupling" or "along with a rubber coupler" if you go that route due to pipe (lack of) vertical motion.
If you had to clean it out once, you might need to again. If not using a cleanout, that votes in favor of the rubber coupling, since it's removable "next time."