View Full Version : Help with vent design.

03-08-2007, 08:25 AM
I'm remodeling my bathroom. The main problem I have is that all my fixtures (toilet, sink, and shower) will exceed the maximum distance from trap to vent; therefore, I have to install new vents. Letís take the toilet for example. Its 12' from the soil stack/vent. I was going to run a tee off the fixture arm, extend a vent vertical about 5 or 6 inches, then using an elbow run it horizontal about 1.5 feet to the base of the wall. I would then run the vent vertical through the wall and into the attic where I'd run it horizontal to the main vent. Is this acceptable?

03-08-2007, 05:41 PM
vents cannot run horizontal until they are 42" above the floor level of that bathroom.

03-09-2007, 03:11 AM
Actually I do believe vents can have graded horizontal runs below flood rim level )below floor, slab etc...), but they should be avoided if possible and when done, drainage fittings must be used...

03-09-2007, 04:30 AM
1 town I work in will not allow anything but straight up to above the flood rim or 42" which ever is higher B 4 you can angle at all.

And absolutely no flat venting of any kind anywhere I have worked.

03-09-2007, 04:55 AM
Our inspectors are at least smart enough to know that a vent on an angle is not horizontal.

03-09-2007, 01:13 PM
I had my bathroom all planed out but this plumbing thing is a nightmare! My toilet is going to be 12 feet from the main soil stack/vent, therefore I need a vent. I'm running 3" piping from the flange to the stack. If I can't run a vent off the fixture arm as I mentioned above, does anyone have any ideas how I can run a vent? I'm having a similar problem venting my shower drain but if I can learn how to vent this toilet, Iím sure I can used the same concept for the shower which is 15 feet from the stack. Thank you for all your help so far! I really appreciate it!

03-09-2007, 02:30 PM
Sketch us a quick floor plan...
There is probably a solution to your problem...
As well, tell us where you live...
Codes do differ from place to place...

03-09-2007, 03:29 PM
Here is a rough drawing (Don't have CAD at work :) ) I hope I attached the picture correctly. If you need any more information please ask as I need all the help I can get. Thank you again! The soil stand/vent in the picture is actually just the vent. The toilet sites right on top of the soil stack and the vent branches off the stack with a "y" fitting. It's an older house with all cast iron. I'm probably going to rip out the cast iron from the ground up and make it all PVC. Also the picture showes the new closet flange offset from the soil/stack, but it's directly inline. I don't think that matters but I though I'd add it anyways.

03-09-2007, 03:30 PM
Forgot to tell you where I live. I live in IL.

03-11-2007, 05:36 PM
Please explain better about the stack. Your toilet's going to be capping the stack? No arm at all?

There's another vent 12' away?


03-14-2007, 03:30 PM
Currently the toilet is above the stack and there is a vent that comes off the stack to the roof. I'm moving the toilet 12 or so feet away from the stack and am going to conect to the stack with 3" pipe. I just need to know how to vent that 12' long fixture arm going from the toilet to the stack.