Hi, I've read through some other posts here looking for info on adding a sink for a basement bar. I'm finishing the basement in my ~3 year old house and I've pulled permits for everything. I've passed my HVAC inspection and am now moving on to plumbing. I'm doing the work myself for the most part. I have two questions.

1) How do I tie into the main stack with the drain from a bar sink? I can place the sink within 2' of the PVC stack pipe, but due to the location of the cleanout, I am unsure of how to proceed, and what heights are acceptable for the tie-in location. I have a tape measure in the pic to provide a reference for the height of everything.

2) With the sink being this close to the stack, do I need to have a separate vent line for the sink? There are many fixtures above tied into the stack. From reading other posts, I'm confused. If I do need to vent it with a separate line, There is a vent pipe for a bathroom rough-in (also in the basement) about 15' away. I can get to it with PVC if I need to. I can tie into this around the 1st floor joists, well above the future bathroom sink. From there, the vent PVC runs up through the 1st floor and ties into other 1st floor vent pipes before going to the roof.

I would cut the stack about 2" above the concrete and glue a new wye and 45* to the stub. On top of the wye, a 4x2(or 4x1½ ) sanitary tee with the cleanout on top of the sanitary tee. The sink would drain into the sanitary tee and run a vent for the bar sink to the future bath vent location(or use an AAV if allowed).



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from what i can see, it looks like the plumber did a nice job..

cut the pipe 1 3/4 off the floor.
cut the pipe a few inches below the "Y"

make a cut a few inches above the 45.
glue a 4 x 2 sanitary tee onto the stub sticking out of the floor.
face the san tee to the side.
holding the existing pipe in place make a cut below the "Y".
this piece can now go back BUT you will need a shielded rubber coupling to make up the joint above the 45.
out of the 2 inch branch of the san tee put a short piece of pipe.
on that pipe put a 90 facing up.
a short piece in the 90 with a san tee on it.
the center of the san tee inlet will be about 18 inches off the floor.
the vent for the sink comes out the top of the san tee and ties into the vent you mentioned in your post.

...



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Packy drawing makes sense I think. Only thing I do't get is, why do I need the rubber coupling? If the idea is to be able to get the pieces back together, I think I will have play for that. The 4" PVC does not go straight up to the roof, it runs sideways to another point in the basement where it goes up through the second floor and the roof, so I think I can prob get 2" of play in the horizontal run to be able to refit the upper section after installing the Wye. Does that make sense and eliminate the rubber coupling from the plan? Also, is there a minimum or maximum slope that needs to be maintained for the vent pipe? I'm assuming there isn't a max distance for a horizontal run like there is for a waste line? It's about 20' to the vent pipe in the bathroom rough.

Thanks for the help!

if you have up and down movement in the stack then no rubber coupling is needed.
there is a maximum distance for venting but my code (I think) says about 50 feet.
so 20 feet is not too far.
there is a slope required for vents but 1/8 inch per foot is allowed.

great, thank you.

Sorry, one more question. To make room for the sanitary 45 at the bottom, I'll be removing a section of the vertical 4" above the cleanout 45 because the new 45 will be taller than the space available. In the end, the cleanout will end up being a little higher, yes?

Correct.

page 39 of charlotte pipe fitting dimensions lists a 4 x 1 1/2 inch sanitary tee as having an overall height of way less than 10 inches.
you have plenty of room to fit this under the cleanout "Y".

[www.charlottepipe.com]

Thanks for all the help Packy.



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