Connecting 2" drain to 3" Toilet drain?

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thetoolsmith

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I'm trying to plan out my new plumbing to connect a wall hung toilet to and existing 2" drain and vent. In the image below the new wall hung toilet is covered in black plastic to help keep things clean. The old 3 inch drain is in the left bay and turns vertical down through a 2x4 supporting wall near the new toilet. This old 3" plumbing can be removed (hopefully)
plumbing-2.jpeg



I've sketched out what I hope will work using a 3x3x3x2 Hub Sanitary Tee with 90 Left Inlet to connect the revamped 2" drain/vent to the new 3" drain. I'm assuming I can cap the top 3" opening if this setup works. Does this setup look like it will work? Do you see any issues?

plumbing-take2.png


Thanks for any feedback!
 

Jeff H Young

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What about going below and offset the 3inch drain on the verticle and come through the top plates on other side of joist? you got a ton of water pipe there though
 

thetoolsmith

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What about going below and offset the 3inch drain on the verticle and come through the top plates on other side of joist? you got a ton of water pipe there though
Unfortunately with the 2x4 wall I would end up removing an entire section of the stud to do that...
 

thetoolsmith

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Another idea I had is instead of using a 3x3x3x2 Hub, is using a Double 90 Hub with a 3 to 2 reducer to pick up the 2"drain. This would require me to move my 2" pipe one more bay to the left but I can do that easy enough...what do you guys think?

 

John Gayewski

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I don't see why they wouldn't work as long as your trap arm lengths are within range.

I think i would probably just 90 over to the toilet then a regular 3x2 wye just after the joist. This would put your wet vent connections in the next host bay over.

A sanitary Tee can't go on its side either. You have a wye labeled as a tee.
 

thetoolsmith

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I don't see why they wouldn't work as long as your trap arm lengths are within range.

I think i would probably just 90 over to the toilet then a regular 3x2 wye just after the joist. This would put your wet vent connections in the next host bay over.

A sanitary Tee can't go on its side either. You have a wye labeled as a tee.
Thanks for the feedback John, I like you're idea better. I assume you're talking about adding a 3x2 wye here correct?
plumbing-take3.png
 

Jeff H Young

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Is the wall that the 3 inch is coming up supporting joists that cantilever? if not how would the hole cause a problem right over a wall? it might or might not raise eyebrow of an inspector but from a practical point of view Is it a concern ?
Additionaly if the 2 inch line marked "Existing drain and vent " might not have a length limitation maybe clarify whats going on there
 

thetoolsmith

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Is the wall that the 3 inch is coming up supporting joists that cantilever? if not how would the hole cause a problem right over a wall? it might or might not raise eyebrow of an inspector but from a practical point of view Is it a concern ?
Additionaly if the 2 inch line marked "Existing drain and vent " might not have a length limitation maybe clarify whats going on there
Thanks Jeff, The joists are just sitting on the supporting wall below so I agree, cutting a 3 - 3 1/2 inch hole in a 2x10 should work. The "Existing drain and vent" continue another few feet and pick up two sink drains and turns vertical up the wall and continue to a vent on the roof.
 

Jeff H Young

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sounds like a perfect wet vent for the toilet. not sure if you were thinking of it being a vent for the shower as well the shower ptrap would have limits in length from where it branched to the lav max of 8 foot
 

thetoolsmith

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sounds like a perfect wet vent for the toilet. not sure if you were thinking of it being a vent for the shower as well the shower ptrap would have limits in length from where it branched to the lav max of 8 foot
How do you measure the branch distance, the total length of pipe or a direct line between the p-trap and the branch? If I draw a straight line between the two it's 7feet...
 

Chucky_ott

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Are you sure that the 2x4 wall is load-bearing ? It could be just a wall over which the joists span. Maybe it's just a wall for an interior partition on the lower floor (e.g. a closet or bathroom). I would have expected a break in the joists above a load-bearing wall. But that may not necessarily be the case.

I only mention it in in case there's a future renovation and someone decides to remove the wall if it's assumed to be non load-bearing. Will one 4" hole in one joist cause a problem then? Meh!
 

thetoolsmith

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Are you sure that the 2x4 wall is load-bearing ? It could be just a wall over which the joists span. Maybe it's just a wall for an interior partition on the lower floor (e.g. a closet or bathroom). I would have expected a break in the joists above a load-bearing wall. But that may not necessarily be the case.

I only mention it in in case there's a future renovation and someone decides to remove the wall if it's assumed to be non load-bearing. Will one 4" hole in one joist cause a problem then? Meh!
It's one of two walls on the first floor for a hallway so there is another wall 3 feet away holding up the same floor joists. I will need to drill a 3 1/2 to 4" hole in a 2x10...probably close to the max if not exceeding it a bit...
 

thetoolsmith

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Wanted to get some feedback on my current setup for this in wall toilet. Nothing is glued yet, wanted to make sure everything looked good before gluing it up. I'll still need to cut a 3 1/2 inch hole through the joist.
IMG_6018.jpeg
 

Jeff H Young

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Wanted to get some feedback on my current setup for this in wall toilet. Nothing is glued yet, wanted to make sure everything looked good before gluing it up. I'll still need to cut a 3 1/2 inch hole through the joist.View attachment 97274
This looks differant than your sketch the od of the pipe is 3.5 the hub is 4 inch so your hole is over 4 inch plus oblong, then you are going to notch the joist on top a bit away from the wall that will be a big notch and the p trap needs to be at that location for a shower as well? not sure its doable like that if thats the same shower center
 

Chucky_ott

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i think his assembly will actually shift a bit to the right by a few inches. I'm assuming the hole in the sill is the center of the toilet.

That said, I don't know if you can fit the wye and elbow inside the joist space without drilling a hole large enough for the wye's hub. That might be a 5" hole.
 

thetoolsmith

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This looks differant than your sketch the od of the pipe is 3.5 the hub is 4 inch so your hole is over 4 inch plus oblong, then you are going to notch the joist on top a bit away from the wall that will be a big notch and the p trap needs to be at that location for a shower as well? not sure its doable like that if thats the same shower center
Thanks for the feedback, the p trap for the shower in the photo is the old shower which gets removed, and the entire setup gets shifted to the right 4-5 inches so the wye portion is to the right of the joist.
 

thetoolsmith

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i think his assembly will actually shift a bit to the right by a few inches. I'm assuming the hole in the sill is the center of the toilet.

That said, I don't know if you can fit the wye and elbow inside the joist space without drilling a hole large enough for the wye's hub. That might be a 5" hole.
Correct, the entire setup will be shifted to the right and the wye portion will be on the right of the joist so a 4" hole should work. I just placed it there so I could balance the mockup for the photo.
 
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