Experts, how is this rough plumbing plan?

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RedBird52

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The collection of knowledge on this form can not be found anywhere else! Thank you everyone in advance for your comments!

We are trying to plan out a map of the rough plumbing with the following layout in the photo. Basicially from left to right we have a Toilet, a vanity, a shower, and then the stack. (I feel like normally in better planned bathrooms, the toilet is closer to the stack -- that is not the case here) Here is a simplified drawing. I will post a more complicated drawing too. Can I go Simple (aka what I drew here? or Do I need to go complicated?

Screenshot 2023-11-07 at 2.46.32 PM.png
Screenshot 2023-11-07 at 2.44.20 PM.png

EDIT 11-9-23: TLDR -- for anyone looking on the forum trying to understand the conclusion -- below is the drawing that i came up with, using the help of the forum experts. (less the back to back 90s which should be 45s) Thank you everyone for your help!

Screenshot 2023-11-09 at 10.07.40 AM.png
 
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RedBird52

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EDIT -- Better image below. Ignore this comment, scroll to comment #3!

Here is my more complicated version. It just sucks, because the vanity drain will need to cross ontop of the toilet drain.
Screenshot 2023-11-07 at 2.51.24 PM.png
 
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RedBird52

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And one more time, to make it more clean!

Screenshot 2023-11-07 at 3.07.36 PM.png

In reviewing this image, I think if I go from Wye to Wye with out a 45 degree, than I will be unable to "roll-up" the fitting. So I guess I need to re-draw this....
 

RedBird52

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OK, Ok, I dont want to make things too easy for you experts... But I have some structural challenges.... If the Drawing in Blue is OK, can I modify it with the Part in RED?

1. There is more than 8' of pipe between the sink trap and the toilet, do I need to have the toilet vented separately?
2. Can I 'Loop-Vent' my Vanity/Shower Vent?
3. If above is NOT ok, Can I 'Loop-Vent' my Vanity Only Vent? (This will be a PITA)
Screenshot 2023-11-07 at 3.21.43 PM.png
 

Tuttles Revenge

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I couldn't find if the Massachusetts code covers Boston, but it looks like it. They have some unique items in their code, one of which is:
(b) Bathtub or Shower Wet Vent

In a single bathroom having a common horizontal waste for a lavatory and bathtub, a two inch waste and vent for the lavatory may serve as a wet vent for the bathtub or shower.
(c) Double or Back to Back Bath Installations


In a double bathroom having a common horizontal waste for lavatories and baths, a two inch waste and vent for the lavatory may serve as a wet vent for the baths.
(d) Miscellaneous Wet Venting


  1. A two inch or larger waste pipe installed with drainage fittings may serve as a wet vent.
  2. The lowest portion of this horizontal pipe serving as the wet vent shall be above the top or above the center line of the horizontal drain it serves except as specifically prohibited in 248 CMR 10.16(8)(e).
  3. Toilets in a bathroom below the top floor need not be individually vented if the two inch wet vented waste, serving the lavatories and bath tubs or showers connect directly to the horizontal portion of the fixture branch for the toilet by breaking the centerline or connect above the centerline of the horizontal fixture drain servicing the toilet.
In most jurisdictions the toilet needs to be downstream of the wet vented fixture if not the most downstream in the bathroom group, I can not find such a requirement.. I believe my drawing should be adequate. But maybe others interpretations may provide more info.

1699389575147.png
 

wwhitney

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  1. Toilets in a bathroom below the top floor need not be individually vented if the two inch wet vented waste, serving the lavatories and bath tubs or showers connect directly to the horizontal portion of the fixture branch for the toilet by breaking the centerline or connect above the centerline of the horizontal fixture drain servicing the toilet.
In most jurisdictions the toilet needs to be downstream of the wet vented fixture if not the most downstream in the bathroom group, I can not find such a requirement..
I think you did find the requirement, it's right there in the text you quoted. If you want to wet vent the toilet, you use the two inch waste that serves both the lavatories and tubs/showers--i.e. the wet vent needs to have already picked up the tub/shower (if it/they are wet vented) before hitting the WC fixture branch.

Likewise, the allowance for wet venting the tub you quoted (and I trimmed) specified a 2" waste from the lavatories, with no mention of the WC.

So I don't believe the order of fixtures in your drawing is compliant with the codes quoted.

Cheers, Wayne
 

Tuttles Revenge

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I think you did find the requirement, it's right there in the text you quoted. If you want to wet vent the toilet, you use the two inch waste that serves both the lavatories and tubs/showers--i.e. the wet vent needs to have already picked up the tub/shower (if it/they are wet vented) before hitting the WC fixture branch.

Likewise, the allowance for wet venting the tub you quoted (and I trimmed) specified a 2" waste from the lavatories, with no mention of the WC.

So I don't believe the order of fixtures in your drawing is compliant with the codes quoted.

Cheers, Wayne
But there is no mention of the order of fixtures such as the UPC which clearly states toilets must be downstream of all others. This just says the lav can act as the vent of a toilet in the toilets trap arm provided it enters above the centerline (the odd part IMO)
 

RedBird52

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In most jurisdictions the toilet needs to be downstream of the wet vented fixture if not the most downstream in the bathroom group, I can not find such a requirement.. I believe my drawing should be adequate. But maybe others interpretations may provide more info.
@tuttle, That was so comprehensive. Thank you so much for pointing it out. The center line -- I was not aware of.

Would this drawing be compliant?

Screenshot 2023-11-07 at 4.14.58 PM.png
 

wwhitney

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But there is no mention of the order of fixtures such as the UPC which clearly states toilets must be downstream of all others. This just says the lav can act as the vent of a toilet in the toilets trap arm provided it enters above the centerline (the odd part IMO)
MPC 10.16(8)(b) says "In a single bathroom having a common horizontal waste for a lavatory and bathtub, a two inch waste and vent for the lavatory may serve as a wet vent for the bathtub or shower."

I read that as a two inch waste and vent for the lavatory only, and as excluding a 3" wet vent carrying the lavatory and the WC.

Cheers, Wayne
 

RedBird52

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@wwhitney so how could I add a "dry vent" to the bathroom fixtures then. Would this be sufficient to independently vent the WC?

Screenshot 2023-11-07 at 4.46.06 PM.png
 

RedBird52

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The Wizard (aka terry) had posted this a few years ago. Looks like I can wet vent if I do it in all 3" pipe. What am I missing?

(Source here)

temp.jpeg
 

Jeff H Young

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What about the drawing in post number 5 with the exception of adding a dry vent for tub ? Red bird 52 your dry vent in post number 10 would need to be verticle piping in any normal code except a few places like Ma and NJ where they make thier own code . but what I suggest above probebly would pass your code seems pretty easy but I havent researched it
 

Jeff H Young

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Terry was very good on UPC code . What you are missing is any mention of Ma code in the drawing post 11
 

RedBird52

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What about the drawing in post number 5 with the exception of adding a dry vent for tub ?
Interesting about the shower dry-vent. Could I use a "Sanitary Tee with Side Outlet"?
How long can the horizontal portion of the shower branch be after the trap to the stack (I would be 6')?


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Jeff H Young

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yes but does that stack take drainage from above on another floor? I never used the side outle tsantee but have stacked a 3x3x2 santee on top of the 3 inch san tee . again clearly the vent cant be used for drainage from another floor.
 

RedBird52

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yes but does that stack take drainage from above on another floor? I never used the side outle tsantee but have stacked a 3x3x2 santee on top of the 3 inch san tee . again clearly the vent cant be used for drainage from another floor.
Yes, it does take drainage from above. Ok, scratch that idea.
Back around to my Challenge here. I would have difficulty adding a 'dry vent' to the tub, because of the layout of the room. There is no way for me to go vertical until very far from the tub...

Do we think that MA does not allow for wet vents? (Such as in terry's photo?)
 

Jeff H Young

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there is a wall of some sort 2 inches away from the tub drain ? perfect for a vent plus there is a side wall i presume
 

wwhitney

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Appreciate your patients with me, but I didnt think that I could go horizontal with my dry vent. Would the image below for a dry vent on a tub be kosher?
No, a dry vent can't be horizontal until it is at least 6" above the fixture flood rim. That image is obsolete.

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. Which way do the floor joists run, and if left to right, will the closet flange for the WC lie over the same joist bay as contains the stack? If not, how deep are the floor joists, and will you be able to make 3-5/8" (minimum) diameter hole(s) in them for the 3" WC drain? As the stack receives drainage from above, where can your dry vent extend through the ceiling to ultimately connect to a roof terminal?

Cheers, Wayne
 

Jeff H Young

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nope didnt suggest that..... run a 2 inch line ove to the tub wall arund a ft deep then 90 up with long sweep on top of 90 place a 2 x1 1/2x1 1/2 san tee with ptrap below floor vent rises up through the floor and then take it wherever you need.
floor joists? I thought this was on concrete ?
 
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