DIY advice for Infinity drain install and venting

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Dan Park

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You could do it like in the attached drawing. The drawing is an elevation, i.e. up-down the page is always vertical. Note that the vent takeoff for the shower dry vent has to be a combo, but you've drawn a san-tee on its back; that's not allowed under the UPC.

The 2" shower trap arm (from trap to vent-takeoff) is limited to 60", and the 1-1/2" lav trap arm (from trap under the sink to the san-tee) is limited to 42". Each trap arm is also limited to one pipe diameter total fall. Oh, and if it's more convenient to jog the vertical section of the 1.5" lav vent or drain (since your original drawing had the san-tee farther to the left), you can do that with a pair of 45s.

Cheers, Wayne

View attachment 80632
Thanks Wayne for that mockup!

Yes Combo after the P trap (looks like a sani tee but with a longer 90) I think I know what you mean. Thanks for that tip!

However, I'm not sure I have the maneuverability to do a vertical stack off the shower P trap the way my main line is oriented. Here is a top view of the bathroom layout and the mainline is in black ink.
20220202_102635.jpg

I can however do a short sloped horizontal run and use med/long 90s like below:
20220202_103247.jpg


20220202_103540.jpg

I understand it's not to code but I'm not getting inspected so I'm not worried about that. But will this way work as well or will this cause some sort of issue down the line?

For the Lav/sink area, I've considered that option as well and believe me that would be the cleaner and proper way, however it will require me to jack hammer a ton of footing out and I was worried I'd accidentally hit the main line abs and make things worse since they encased everything in concrete. (Super deep footing under an interior wall ‍‍♂️)
 

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Dan Park

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Yes. The vent wants to be vertical from the point of connection to the drain, Unless Prevented by Structural Conditions, then the vent can be installed horizontally with proper drainage fittings to the point where it can become vertical. Ultimately its going to be your inspector who determines whether you meet that threshold (pun intended)

As further useless information. The change in wording for exclusion of a threshold was inserted in the 2012 UPC.
Thanks Tuttles, I think I'll revert to my initial concept pic
S0g0o.jpg


But I'll just make sure to add med/long 90s and make sure my trap arm is 2x greater than the diameter of pipe after the P trap.
 

wwhitney

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In your floor plan, can you add some lines (use different colors) that show (a) where you expect the footing to be thick (i.e. more than a 4" concrete slab to go through) and (b) which part of the buried drain is existing vs proposed?

Also, how deep is the existing 3" drain you are tying into? And if the 3" drain doesn't current extend to the exterior wall at the top of the page, are you wanting to do that just to add a cleanout, or is it required, or?

Lastly, it looks like you plan on a fixed glass partition between the WC and shower, if so would you be averse to a pilaster (wing wall) where the glass hits the wall, i.e. a short 6" to 12" long 2x4 wall from floor to ceiling?

Cheers, Wayne
 

Tuttles Revenge

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Now that I see the plan view.. *edit* I'll try to come up with a conforming drawing.
 
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wwhitney

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Now that I see the plan view.. way way simpler to just do it as a horizontal wet vented system. I can do that in 6 fittings underground
If your proposal is just the solid black line, it has a few issues. The only dry vent I see is at the lav. Then you can't join the WC and the shower together unvented. The shower drain has to join the lav first, then the shower/lav drain can join the WC. The UPC requires the WC to be last on the horizontal wet vent. [Except in WA, where they've eliminated that requirement, but the OP is in CA.]

Also, the shower trap arm length is limited to 60" under the UPC. Looks like the the trap may be more than 60" from where it would join the lav. If it isn't, then the fixture ordering problem could be fixed by routing the WC drain over the shower drain to join the shower/lav downstream of the shower/lav joint..

Cheers, Wayne
 

John Gayewski

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If you can run your vent as you show in your very first picture why can't you run the trap arm off of it? Meaning scratch out the drain part that is currently shown down low. Only have the drain come off of the pipe you want to run as a vent.
 

Tuttles Revenge

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If your proposal is just the solid black line, it has a few issues. The only dry vent I see is at the lav. Then you can't join the WC and the shower together unvented. The shower drain has to join the lav first, then the shower/lav drain can join the WC. The UPC requires the WC to be last on the horizontal wet vent. [Except in WA, where they've eliminated that requirement, but the OP is in CA.]

Also, the shower trap arm length is limited to 60" under the UPC. Looks like the the trap may be more than 60" from where it would join the lav. If it isn't, then the fixture ordering problem could be fixed by routing the WC drain over the shower drain to join the shower/lav downstream of the shower/lav joint..

Cheers, Wayne
You're right.. I shouldn't put out non conforming drawings even if he isn't getting inspected. I'll remove the drawing and try to revise.
 

Dan Park

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If you can run your vent as you show in your very first picture why can't you run the trap arm off of it? Meaning scratch out the drain part that is currently shown down low. Only have the drain come off of the pipe you want to run as a vent.
Hi John,

Thanks for your suggestion. If I'm understanding you correctly, are u saying to orient the Trap arm off the P trap towards the double stud wall (behind the linear drain), run a vertical vent pipe up the wall off of the trap arm w/ a combo (w/ no horizontal runs), then run maybe a long 90 flat after the combo towards the mainline and connect?
I have thought about that scenario as well but it would require a lot of jack hammering out concrete footing under the double wall, lol. The space may be tight but it probably can be done.

Please correct me if I'm wrong with your suggestion.
 

Dan Park

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You're right.. I shouldn't put out non conforming drawings even if he isn't getting inspected. I'll remove the drawing and try to revise.
Thanks Tuttles, I do appreciate your suggestion and I have thought about doing it that way and adding the 2nd vent stack off the mainline after the shower drain.
But I do see Wayne's point of having a vent after the Trap arm so the water can properly stay in the shower's P trap to block out the gases. I'm assuming if I don't, the downflow suction towards the mainline might suck out the P trap water enough for gasses to go up the shower drain. Is that the right way to think about it?
 
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wwhitney

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Thanks Tuttles, I think I'll revert to my initial concept pic
That horizontal dry vent under the slab is not allowed. The code provisions are generally in place to ensure good functioning, and that applies here.

If you provide the info requested in post #23, I'm happy to think about a code compliant solution that would minimize jack hammering through footings, pretty sure there will be some options.

Cheers, Wayne
 

Dan Park

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That horizontal dry vent under the slab is not allowed. The code provisions are generally in place to ensure good functioning, and that applies here.

If you provide the info requested in post #23, I'm happy to think about a code compliant solution that would minimize jack hammering through footings, pretty sure there will be some options.

Cheers, Wayne
Will do thx!
 

John Gayewski

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Hi John,

Thanks for your suggestion. If I'm understanding you correctly, are u saying to orient the Trap arm off the P trap towards the double stud wall (behind the linear drain), run a vertical vent pipe up the wall off of the trap arm w/ a combo (w/ no horizontal runs), then run maybe a long 90 flat after the combo towards the mainline and connect?
I have thought about that scenario as well but it would require a lot of jack hammering out concrete footing under the double wall, lol. The space may be tight but it probably can be done.

Please correct me if I'm wrong with your suggestion.
I tried to upload a drawing. It didn't work.
 

Dan Park

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That horizontal dry vent under the slab is not allowed. The code provisions are generally in place to ensure good functioning, and that applies here.

If you provide the info requested in post #23, I'm happy to think about a code compliant solution that would minimize jack hammering through footings, pretty sure there will be some options.

Cheers, Wayne
20220203_141612.jpg


Hi Wayne, I hope this makes sense. I didn't have another color so I just made the footings squiggly lines. The footings is roughly 1.5-2ft deep.
The existing 3" mainline is in solid black lines. The proposed extension to the main line is the dotted lines.

Going off of what John said, maybe I point the trap arm of P trap towards the double stuck wall and run a dry vent up that wall, then swing it back around to try to tie it into the mainline extension?
 

John Gayewski

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Just like your very first picture. Delete thr lower drain. Sanitary tee right onto the riser.

If your plan was your very first picture then this should be exactly the same except where your vent was going to come up the wall you start the trap arm there. You could run everything up stream of the toilet in 2" pipe as long as there's not another toilet.
 

Dan Park

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Just like your very first picture. Delete thr lower drain. Sanitary tee right onto the riser.

If your plan was your very first picture then this should be exactly the same except where your vent was going to come up the wall you start the trap arm there. You could run everything up stream of the toilet in 2" pipe as long as there's not another toilet.
20220203_151340.jpg


So something like this if I were to breakdown the components?
 
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