Another basement bathroom

I'm considering the idea of tackling the basement bathroom but before I start I'd like to know if I'm on the right track. I've broken out much of the concrete floor around the stack and have opened a portion of the wall on the first floor to see what was going on with the venting and drains, there is no second floor bath. Originally, I thought I'd hire a pro to do the work, but now that I see what's going on and after doing a little online research, I thought I might try this myself. (I've also done some basic plumbing in the past.) I'm still a little leary, so hiring someone may still be what ends up happening but I'd like to know what they're doing in any case. I think the linked diagram is pretty self-explanatory, hopefully it's not too hard to read. If more info is needed, let me know.

I'll let the pros comment but I just had to say ...... gorgeous drawing.

The toilet is not vented correctly and doesnt meet Chicago code. What you should do is coming out of the tee install a short piece of pipe with a 4x2 sanitary tee and a street 90 into it to pick up the toilet. As far as (horizontal) vent bar for basement you can put that double combo at 45 inches of the floor. Also just so you know PVC is not allowed underground in Chicago but I wont tell . Finally make sure the cast iron is braced properly before cutting the stack.

PVC isn't allowed underground in Chicago? What do you use then, ABS?

Where I live we never see PVC anyways, just curious.

dlarrivee said:

PVC isn't allowed underground in Chicago? What do you use then, ABS?

Where I live we never see PVC anyways, just curious.

Click to expand...

Only cast iron is allowed below ground in Chicago.


You can't tie the vent into the existing vent stack until you are a minimum of 6" above the flood rim of the highest fixture

jc60618 said:

The toilet is not vented correctly and doesnt meet Chicago code. What you should do is coming out of the tee install a short piece of pipe with a 4x2 sanitary tee and a street 90 into it to pick up the toilet. As far as (horizontal) vent bar for basement you can put that double combo at 45 inches of the floor. Also just so you know PVC is not allowed underground in Chicago but I wont tell . Finally make sure the cast iron is braced properly before cutting the stack.

Click to expand...

Thanks! I wasn't sure about the toilet, but that makes sense.

Does not tying the vent into the existing vent stack until you are a minimum of 6" above the flood rim of the highest fixture
mean that I can't revent until I'm 6" above the first floor sink?

That means I can't revent until I'm 6" above the first floor sink


Thats correct your going to have to tie into the stack vent

Thought I'd make a re-draw of the diagram after feedback.

Ditto to export!'s comment...great drawing! Would you be willing to share which program you're using for drawings & schematics?

duggerce said:

Ditto to export!'s comment...great drawing! Would you be willing to share which program you're using for drawings & schematics?

Click to expand...

I used Adobe Illustrator. Thanks btw.

By the Chicago Code I used when I was there, it also means that the tie back for the vent has to be at least 42" above the floor, UNLESS the sink is high enough that 6" above it would be higher than 42". 6" above the overflow level or 42" above the floor, is not just an "either/or" requirement. It is a "whichever is higher" requirement.