I am adding a new bath and it is located directly above my existing vent stack. I had originally planned to put a series of bends in the stack in order to move the location of the vertical riser into the new walls above. While looking through the IRC 03 (effective in CT) I noticed a paragraph that stated "waste stack shall be vertical, and both horizontal and vertical offsets shall be prohibited." I am interpreting this to mean my original plan to offset the waste stack is not allowed, but I'm no plumber so I figured I would throw this out there and see what you all thought. Any advice/insights would be much appreciated. Thanks.
I think there's a distinction between "vent stack" and "waste stack" that might save you. Check with your inspector.
I'm kind of a novice at this stuff, so I may be confusing my nomenclature. The stack in question is the only existing vertical pipe in my house. At the base of this vertical pipe all of my drain lines tie in. I believe that would make this pipe a stack vent due to waste entering in? The reason I want to add a jog is that if I just add my tees and continue vertical the pipe will not be in a wall (unless I alter my floor plan). I will add a couple of pictures. One shows the bottom of the existing vertical pipe in my basement. The other shows the top of the pipe as it sits in the new bathroom addition. Any comments/thoughts/suggestions are greatly appreciated!
I have almost the same EXACT setup except my vent and stool connection are reversed! I took my vent down to 1 1/2" up through the wall and up to the roof where I changed it back to 3". Just had it inspected a month ago. I do believe that toilets self vent do they not? Its the other drains that need to breathe I think, I may be wrong.
I think you may be wrong.
Most drains will work fine without a vent...it's the others in the system that will have their traps siphoned dry if the system isn't vented properly.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014
Edlenz is wrong. Toilets are not "self venting".
Most drains will work fine without a vent...it's the others in the system that will have their traps siphoned dry if the system isn't vented properly
This is also mostly wrong.
ALL drains will work BETTER without a vent. That is the problem. They work so good that they siphon themselves, and sometimes other drains. There has to be something to go along with that section of the code cited, because there are MANY times when a stack cannot go "Straight without offsets". In fact architects and engineers seem to delight in drawing designs that have offset walls. But to answer the question as to how to make the connection for you new bath. You CANNOT connect it to the pipe above the downstairs bath. It has to connect below the bath in the section of the piping called the "drain", not the part which is the "vent".
Thanks for the info. It sounds like the installation of the waste/vent system will be more complex than I had originally planned. If I had a nickle for every time I said that! I guess I'll just run a new drain line to the basement and tie in there somehow. I put the roof on last weekend, and I assumed that I should not move the location of the stack, so that bridge has been crossed. I will just box the riser in - not really that big of a deal. I would love to tie my new vent lines into this, so I don't have to put a new vent through the roof. I was thinking I would extend the vents in the wall and connect in the attic space. That would be kosher, right?
Do what I did. I got the inspector to come over and tell me what I needed. He told me where and how big I needed vents and drains. Left it to me how I ran the pipe in some instances. I have done this with the building, and electrical inspector. If you pull a permit, they will make you do it right or at least to their interpretation of the code.
Just a question. Isn't a vent stack a drain? If it rains, doesn't the rain go down the "Vent"? My point is a vent is a vent only if it lets air into the system above the last drain in that run. In my system or area we only need a 1 1/2 " vent to the roof and then at least a 3" to keep the vent from freezing over. A jog in the line isn't a problem. In one vent I have 5 90 degree and 1 45 degree turns before it mates up to a 3" adapter to go through the roof. I am no plumber but Air in a vent doesn't care how many turns it needs to go through in the system. I am sure air won't collect in an area the same as stuff from a toilet.
Last edited by edlentz; 07-23-2008 at 08:36 PM.