Use VEnt Stack for Drain on 2nd Floor?


Old 09-22-09, 05:30 PM
Thread Starter
Join Date: Sep 2009
Location: Missouri
Posts: 2
Use VEnt Stack for Drain on 2nd Floor?

I'm working on a turn of the century foursquare style house. I want to put a bathroom on the 2nd floor in a room directly above the existing bathroom below. There is a 3" air stack that runs up through this room and out the ceiling.

My first thought was to tie my drains into this but it is only 3" and I'm pretty sure the floor joists run the wrong direction so I couldn't line the toilet up with it anyway.

I saw a diagram in a how-to book that showed all the bathrooms in a house draining into the main stack. That didn't look quite right to me.

If I did have room between the floor joists, is this possible? BTW, this is out in a rural county with no plumbing codes.

Here's the picture I was referring to:
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Old 09-22-09, 07:50 PM
Join Date: Nov 2007
Location: Pennsboro, WV
Posts: 70
During the framing, you can cut out and box the joist system to allow the placement you want. You basically put a door header in place and using a joist hanger, you hang the cut joist to it.

Then offset two fill pieces to allow the closet flange.

Old 09-26-09, 12:48 PM
shacko's Avatar
Join Date: Aug 2005
Location: Baltimore County Maryland
Posts: 2,138
Question Plumbing Drawing

Code or no code that drawing is obsolete, you can't hook up anything that is run like that without causing yourself future problems.

The only way you can hook up to a stack with a bathroom below is if all the lower fixtures are vented. There are venting issues that pertain to the upper level also.

If you can tie into the lower stack below the lower bathroom and run from that point that would be the way to start.
Old 09-26-09, 06:46 PM
Thread Starter
Join Date: Sep 2009
Location: Missouri
Posts: 2
Sounds like my first plan. I can run a new drain all the way to the basement and tie it in down there.
Old 09-26-09, 08:56 PM
Join Date: Mar 2000
Location: Arlington, WA
Posts: 9,238
There you go -- run the new drain to the bottom and tie it in there.

The pic that you are showing has the upstairs bath drains tied into the VENT for the lower bath.

Did it work?? Well, KINDA. But then, so did Model "T"s and Model "A"s!!

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