||01-14-2010 06:16 PM
Originally Posted by Heikks2002
I am writing this for information on wether or not I can just tie a 3 or 4 inch pvc pipe into my original stack from a new 1/2 bath I would like to put downstairs. The new bathroom woulc be about 20 feet away from the main vent stack and I do not want to try to run an aditional stack for this half bath. Can I tie this new toilet into my main drain, this drain comes from the bathroom upstairs where it is vented out the roof. thanks for any help .. i have attached a drawing of what i'm looking at ...
Not sure what the code is in Michigan, but here in MA you could certainly tie your new waste pipe from the half bath into the waste stack that serves the upstairs bath, BUT you'd also have to run a new vent for the half bath
. The new vent doesn't have to go through the roof independently (although it could if that's easier to do), but you could tie it into an existing vent a minimum of six inches above the flood-level rim of the tallest fixture on the floor above (e.g. - if the highest "flood-level rim" is a the rim of a sink basin that's 36" tall, you can tie the new vent into the existing vent at 42").
AAV's (Air Admittance Valves - aka: mechanical vents) are prohibited in MA except in extreme circumstances, but maybe they're allowed there? You'd have to check with your local code enforcement official(s).