View Full Version : question on residential soil stacks
larrygman
11-23-2008, 04:59 AM
Hello all. I have a 2 story residence with one bathroom above the other. both toilets wind up in same line top and bottom. can I discharge both toilets into the vertical soil stack? The stack is 3". The soil stack turns into a vent stack above the top bathroom and goes outthe roof.
jimbo
11-23-2008, 06:05 AM
No...................
Taking your question at its basic level, the answer is YES both toilets can discharge into the same stack. BUT, you cannot do it the way your question implies. Doing it correctly is why God made plumbers, and said they had to go to school and have on the job training for five years.
Redwood
11-23-2008, 07:15 AM
To put toilets above the other fixtures makes them not be properly vented. Each fixture must have a vent above the other discharges into the stack.
Maybe this picture of a DWV system will help you understand the concept.
http://i44.photobucket.com/albums/f2/Redwood39/sizing-4.jpg
larrygman
11-23-2008, 01:03 PM
Redwood thank you for you reply and diagram. To take this a step further, I did intend to vent all other fixtures below the second floor toilet. I will be bringing all other fixture vents up above the flood level of that toilet on the second floor and connect them to the portion of the soil stack which becomes the stack vent. Does this sound ok?
Thanks ,
Larry
Redwood
11-23-2008, 03:06 PM
That would be okay if done properly. It's a lot of work though and usually it is far easier to run a new waste line to below the 1st floor fixtures.
larrygman
11-23-2008, 03:45 PM
Thanks Redwwood. Im going to look tommorow if I can find another bay to get the upper toilet down seperatly.
Lar
Redwood
11-23-2008, 03:47 PM
It would eliminate reventing everything below.
Terry
11-23-2008, 04:34 PM
http://terrylove.com/images/dwv_b2.jpg
SewerRatz
11-24-2008, 12:39 AM
To put toilets above the other fixtures makes them not be properly vented. Each fixture must have a vent above the other discharges into the stack.
Maybe this picture of a DWV system will help you understand the concept.
http://i44.photobucket.com/albums/f2/Redwood39/sizing-4.jpg
Wow Redwood that diagram is older than I am. Love that running house trap. At least that one is in the basement with clean outs on each side. Around here the running traps are usually in the parkway with a vent that got buried 50 years ago.
You do not vent "all the other fixtures" on the lower level. You vent "ALL the fixtures" on the lower level including the toilet. There is no reason not to connect it to the drain from the upper level, as long as you do it CORRECTLY.