View Full Version : To Vent Or Not To Vent...

08-23-2011, 06:16 PM
I would like to know which of the following 2 alternatives has a better chance of working.

I have a 6x5 1st floor closet that I want to put a toilet and a sink in to make into a powder room. I have hot and cold water directly underneath. My only issue is the drain/stack.

At 9’6” from where I want to put the toilet, there's a roof vented 3" PVC drain/stack running vertically in a nearby wall from a 2nd floor bathroom and laundry room. As soon as this drain/stack gets to the basement through the 1st floor, there are 2 - 45 degree turns and the 3” PVC slopes slightly downward to the 4” main drain. Because of some ducting in the way, it will be difficult (but not impossible – it would have a lot of turns) to tie the new toilet to this drain.

The other choice is 30’ away just about where the main drain leaves the house. It’s a straight run that I can pitch at any angle, even having a vertical drop or an angular drop to a wye where it meets the main drain. I would run 4” PVC from the new toilet to the 4” main drain. The nearest vent to the intersection of where the 4” pipes would meet is 12’ “upstream” where there is another 3” PVC drain stack running to the other 2nd floor bathroom and is vented to the roof.

Any thoughts on which approach is better would be appreciated.