Rerouting kitchen drain through floor vs wall

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edee_em

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Hi. I was thinking of rerouting a kitchen sink drain down through the floor instead of having it run across another cabinet and back into the wall (as shown by black lines). I was wondering if the change proposed (red lines) is proper. The old drain line would be capped off and the vent would remain. My concern is that the change looks like it is taking on the dreaded S-trap shape. I also included a pic of the situation for reference. Thanks
Untitled2.pngkitchen sink.jpg
 

edee_em

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You are correct in thinking the drop down would be an S-trap and not meeting code requirements.
That's the bad news. Is there any good news such as what I would need to do to avoid it?
 

Diehard

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Well if you want to drop within that cabinet, an AAV(Air Admittance Valve) could work, if allowed by your governing plumbing code. Most codes allow it.(Not so sure about this statement.)
It would look something like this...
Maybe add a cleanout in the drop.
 

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edee_em

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Thanks, Diehard, but our sink takes up most of the cabinet and I'll have to check whether I can get an aav up high enough and accessible. There is a height recommendation, isn't there? Is there any way of using the existing vent?
 

Diehard

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The following is a paragraph from the International Plumbing Code. Don't know about Uniform Plumbing Code or other states.

IPC AAV Location.jpg
 

Diehard

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What does the plan view of the piping in the adjacent cabinet look like?

@frodo...I think the vent has to connect to the drain line, as well. Also, is an island venting system acceptable for a non-island application? I have no clue.
 

frodo

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He is making it an island by cutting it off from the drain

The code does not say you cant

My question is WHY?
What he wants to do does not make any sense to me
If the goal is to rid the side cabinet of the drain line
then that is not going to be accomplished.
The existing pipe needs to be capped off , the cap will be an obstacle just like the pipe is
This will leave the same amount of room as is present now

My suggestion is a whole lot simpler
move the 45 back and hug the wall with the pipe
cover the piping with a panel. all of this can be done in a 2'' space
 

Diehard

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Yes. That's part of the reason I asked about, "...the plan view of the piping in the adjacent cabinet ". We don't really know what that looks like.

I agree we really don't have the full picture of WHY.
 

Diehard

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Oops!
Believe or not, I was thinking that was one cabinet with multiple doors and that the pipe we see to the left was going into the adjacent cabinet.

Based on you opening my eyes and brain, I have to agree with your original suggestion of running it tighter to the back wall. I probably wouldn't even bother with the added panel.
 

edee_em

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OK. Here's the "why". That drain line is leaking. Also, the vent and tee are behind the wall behind the cabinets. So, I have to find the leak and fix it.

The plumbing in the left cabinet (12" cabinet to left of sink cabinet) has a vent line above and then makes its way into the basement toward the stack but it looks like there is a 45 to take it out from the wall and then two more 45's in the rim joist bay in the basement to get it going in the right direction to the stack. There is also an old sani-tee which picked up the upstairs laundry (now abandoned).

That line ended up being the reason for some flooding and mold I had in the basement. A fitting before the stack had cracked and it was fixed. However, the tee in the rim joist area also had a crack and it kept leaking. I replaced all the abs from the floor down barely getting a coupling in to the pipe left after cutting out the old piping. I don't think I got the top coupling glued on properly as another leak developed.

So, I want to plan options for how I'm going to fix this issue. I'm asking about rerouting the drain here but I was also thinking about boring out the wood around the drain pipe in order to get more room to properly attach a coupling. Just trying to plan a fix without making it more difficult.
 

edee_em

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ABS glue but it might have been old, if that's a thing. The other connections I made seem to be holding properly, so I don't know. My worry is that the leak could be from the tee joining the vent and sink drain (which would require me digging into the wall). The pic shows things below the floor into the basement.

The issue is that if I cut out the pipe from the coupling at the floor, to rebuild the drain, I will have very little pipe to join a new coupling on to. I hope it shows up in the pic that it comes through some 2x material. I was thinking of expanding that hole and digging it a bit deeper so I can get a new coupling in place. That is why I was asking about the drain through the floor option.
20200401_205834.jpg
 

edee_em

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Turns out it wasn't the coupling causing the leak. The pipe the coupling is attached to is cracked. Nice lengthy crack going up towards the drain/vent tee. Going to have to go into the wall to replace. Should have seen that before putting the coupling on. Oh well; live and learn and never, ever charge anyone anything for my plumbing expertise!!
 

bartleyhs

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I have a question. The OP has had a LOT of cracks on the ABS pipes and fittings. What in the heck causes that? I though ABS was pretty sturdy stuff.
 

frodo

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ABS is outlawed in my state because of that.
I live in a high humidity/ high summer heat climate
the ABS gets soft then turns back hard, then soft. ETC ETC
it finally cracks
 
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