I want to install a toilet in my upstairs bedroom. I was told that I cannot connect to the 3" vent line for the downstairs toilets. the main reason being that a vacuum will be created when we flush the upstairs toilet and cause the water to be removed from the downstairs toilets. also that any home inspector will not pass the permits with that kind of configuration. He recommended that I run a drain/vent line using the exterior cleanout port, up the exterior of my home directly to the room in question.
has anyone ever done this before? I cant seem to find any information online about this.
what should I be worried about with this "exterior" drain? Any information would be helpful.
Best Answer
In Illinois this wouldn't be a problem provided it adheres to everything on this list and fits these numbers. Your concern may be that the stack is not a clear vertical run to the roof or that the toilet flange will be more than 24" from it.
My codes expect 4" stacks to begin with. A lot of people seem to get away with 3".