Experts, how is this rough plumbing plan?

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RedBird52

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I could make a suggestion on DWV layout for the bathroom, but I need a bit more information than is in the diagram in the OP.

Wayne, thank you so much! The joists are new 2x10s (so really 2x9s...) but I would be willing to re-frame the floor as needed. Or use these things. MY challenge is the area is box'ed in by 6" beams. See photo.
Screenshot 2023-11-08 at 9.02.58 PM.png
 

Jeff H Young

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On the Toilet vent Im assuming its a verticle dry vent and not run horizontal below flood level of the W/C as it apears to possibly be drawn? that would be prohibited every where I know of
 

RedBird52

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On the Toilet vent Im assuming its a verticle dry vent and not run horizontal below flood level of the W/C as it apears to possibly be drawn?

arg, really appreciate it. you caught another error. The dry WC vent [in red] goes horizontal under the floor, rolled up with a wye. Now that you have identified the issue, I understand/agree what I drew was incorrect. Arg,,,,
 
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RedBird52

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run a 2 inch line over to the tub wall arund a ft deep then 90 up with long sweep on top of 90 place a 2 x 1.5 x 1.5 san tee with ptrap below floor vent rises up through the floor and then take it wherever you need.

I thought this was on concrete ?

ah, I see what you are saying. I will try and re-draw that. Would the flood-plane of a shower basin (as it relates to a vent) be considered 6" above the bottom of the shower pan?
 

RedBird52

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OK, my latest drawing! Toilet/sink wet-vented. Shower dry vent, with vent being 5 feet from the shower trap. 2" on Shower branch, and then 1.5" vent going vertical into a Wye turned on its back!

Screenshot 2023-11-09 at 10.07.40 AM.png
 

wwhitney

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The venting on your last drawing is OK. With a 2" shower trap, you are allowed up to 6' of horizontal pipe run, and at most 2" of total fall, between the trap outlet and the upright wye that is your dry vent takeoff.


But the two 90s in a row is probably not optimal. You have a degree of freedom at the trap by rotating the joint between the u-bend and the outlet elbow (those don't have to be coplanar), so you can take advantage of that. And if you do need to do a parallel offset anyway, use two 45s rather than 90s if at all possible.

Cheers, Wayne
 

RedBird52

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Experts thank you so much for your help so far! @Wayne -- you are awesome. Would love to buy you a beer next time you are on this coast.

Could we talk for a moment about the dangers of using a Sanitary tee With side inlet? I always thought these things were just not kosher. But perhaps I can use this here?



Screenshot 2023-11-09 at 8.28.34 PM.png

My ability to draw in 3-d is poor, but does the image here make sense? Would it be legal?

Screenshot 2023-11-09 at 8.30.37 PM.png


Screenshot 2023-11-10 at 8.50.08 AM.png

I think this is a side inlet with "Drainage Pattern". So I *THINK* I'm ok, But experts Please chime in.
 
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Jeff H Young

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Ive never used a side inlet seldom seen used So just something Ive never done or had a need to use and dont see a need here
 

RedBird52

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Hello Experts! I am swing back to this project. Took the advice to abandon the Tee with side inlet.
Problem with the design below is the vent under the tub goes horizontal. Is this ok?

1725480565966.png
1725480737373.png
 

wwhitney

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Hello Experts! I am swing back to this project.
I did not review the earlier part of this thread but am just responding to the new rendering.

Problem with the design below is the vent under the tub goes horizontal. Is this ok?
No.

If the run length to the wye where the tub drain joins the lav is short enough, then the lav can wet vent the tub as well as the WC. If you need a longer allowable length, you can use a 2" tub trap and trap arm instead of 1-1/2". Massachusetts has its own plumbing code, so you'll have to check it to find the applicable limits. [But the fall is always limited to one pipe diameter, so the maximum allowable run is never more than 6' for 1-1/2" and 8' for 2", based on the exact minimum 1/4" per foot fall. Some plumbing codes have shorter allowable lengths, perhaps as a recognition that the fall will rarely be the exact minimum.]

If you need to reduce the run length you could have the trap arm for the lav go to the right (as you face the lav) to a san-tee to the right, then the tub/lav wye would be closer to the tub.

Or if you prefer a dry vent takeoff, you could put one "around the corner", just use a wye (or combo) rolled 45 degrees for the vent takeoff, just like the one where the lav joins the tub drain.

Cheers, Wayne
 

RedBird52

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If the run length to the wye where the tub drain joins the lav is short enough, then the lav can wet vent the tub as well as the WC.
Great call out, but Negative I am at least 8.5ft (probably closer to 10ft) of run between the shower trap and the vertical rise for the Sink vent.
If you need to reduce the run length you could have the trap arm for the lav go to the right (as you face the lav) to a san-tee to the right
This is genius. Let me attempt a render!
 

RedBird52

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Here are the renders per suggestions. Single wet 2" vent! Shower trap will be just under 8ft of horizontal before it goes vertical [blue] portion of the Lav Vent [it will be close!]. It will certainly be within 8ft of the 3" Wye.
1725570666619.png


1725571212714.png


Excellent suggestion!
Am I looking to code in this diagram?
 

wwhitney

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Looks like Massachusetts only allows you 6' from trap to vent takeoff for a 2" trap and trap arm.


Also, there's no reason to upsize at the shower/lav wye to 3". You can use 2" all the way to the wye with the WC.


Cheers, Wayne
 

RedBird52

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@Wayne -- another great call out with the MA specific plumbing code! (thanks so much for the help). So I need to keep "6' from trap to vent takeoff." Is that six feet measurement represented by the red line or the green line? (Please say red!)

1725631424914.png

Am I required to "roll" these Wye's? Can the blue wye attached to toilet be kept flat?
1725630402243.png

Any other issues with design?

1725631530782.png
 

wwhitney

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Yes, the trap arm is the red line.

As to the blue wye, MA seems to have a weird rule that it can't be horizontal as you've shown. You need to use a 3x3x2 wye, with the 2" inlet rolled up just a little, as per the Example 11 in the link I provided. Not something that is in any other plumbing code I've looked at.

Cheers, Wayne
 

RedBird52

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Man, glad I asked. Nice catch.

1725650031896.png


note the intentional error below. In blue I have a "tee" not a "wye". My cad program does not have a 3x2x3 Wye... So I see that needs to be fixed!


1725650487660.png



1725650604306.png


how are we looking?!
 

wwhitney

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Look good as long as the trap arm lengths are within the maximum length allowed. I didn't look up what that is for the lav.

Note that if the blue fitting is a "tee" configuration as drawn, it would need to be a combo instead of a san-tee on its side. And using a combo plus a LT90 there works. But using a wye plus a 45 would be preferable.

You can use a wye plus a street 45 (with parallel inlets, not in the "combo" configuration) if you get the 2" lav/shower drain parallel to the 3" WC drain at exactly the correct distance apart. Which if you are not otherwise constrained would be a nice way to do it.

Cheers, Wayne
 

RedBird52

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Amazing wayne!!

1725657884054.png

my image shows a wye 3x1/5x3, becuase my program is missing the required 3x2x3 wye.

But I caught a miss-speak in your answer "You can use a wye plus a street 45 (with parallel inlets, not in the "combo" configuration) if you get the 2" lav/shower drain parallel" -- This would need to be a Street 60 if I roll up the 3x2x3 wye per MA code! I only could catch this becuase of all of the knowedge you have shared with me on this forum.
thanks so much!
 
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