ABS to Wall Hung Toilet through a Floor Joist?

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thetoolsmith

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I'm installing a Toto wall hung toilet as part of our bathroom renovation and wanted to get some feedback on putting a 3" ABS pipe through an adjacent 2x10 floor joist that sits on a wall partition below. Hopefully with my sketch and photos I can relay what I'd like to do. The current 3" pipe runs horizontally from the old toilet and then turns 90 degrees vertically down the wall. The drain pipe on the right will be removed (it's from the old shower) The pipe which runs perpendicular to the right is tied to the vent so that'll stay.
IMG_5970.JPEG

Our new Toto wall carrier is under the black plastic to help keep it clean while we renovate. Ideally I would like to replace the 90 that turns down the wall and use a combination long radius tee-wye and drill a 4" hole through the 2x10 to reach the new toilet. I know this violates the 1/3 rule but I'll be able to keep at least 2" on both the top and bottom of the 2x10 which is supported directly below by the wall downstairs.
IMG_5971.JPEGIMG_5973.jpegplumbing.png

Does this seem feasible or is this just a bad idea altogether?

Any tips or feedback would be greatly appreciated.

Thanks!
 

wwhitney

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Two issues: the outlet elbow just inside the wall provided by Toto I believe is required to have its outlet downward or at most 45 degrees from plumb, as it completes the WC S-trap that provides the siphonic emptying of the bowl/internal trap. So that would rule out pointing it sideways as you've drawn. Check the manual for confirmation.

Second, where a joist is passing perpendicularly over a bearing wall, then the joist is in compression vertically. So that's a bad place to drill any hole, let alone an oversize one (not sure if the IRC actually regulates that, though). If, however, the joist is passing over a non-bearing wall, then I think (not sure) that is a slightly better than typical place to put a hole, assuming you could count on the non-bearing wall to actually provide a little extra support for the compromised joist.

So figure out whether the wall below is bearing or not. Either way you'd still want to reinforce the joist with the oversized hole, e.g. with a product like those at joistrepair.com. But if it's bearing, that would complicate the reinforcement design.

Cheers, Wayne
 

thetoolsmith

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Two issues: the outlet elbow just inside the wall provided by Toto I believe is required to have its outlet downward or at most 45 degrees from plumb, as it completes the WC S-trap that provides the siphonic emptying of the bowl/internal trap. So that would rule out pointing it sideways as you've drawn. Check the manual for confirmation.

Second, where a joist is passing perpendicularly over a bearing wall, then the joist is in compression vertically. So that's a bad place to drill any hole, let alone an oversize one (not sure if the IRC actually regulates that, though). If, however, the joist is passing over a non-bearing wall, then I think (not sure) that is a slightly better than typical place to put a hole, assuming you could count on the non-bearing wall to actually provide a little extra support for the compromised joist.

So figure out whether the wall below is bearing or not. Either way you'd still want to reinforce the joist with the oversized hole, e.g. with a product like those at joistrepair.com. But if it's bearing, that would complicate the reinforcement design.

Cheers, Wayne
Thanks Wayne, the Toto outlet will be vertical, I didn't do a very good job of labeling my drawing...the top image is looking at it horizontally, and the bottom drawing is looking at it from a birds eye view. I've done some more research and the combination tee isn't recommended in this case so I've decided to use a 3" tee instead. This in turn puts the connection at the top of the joist where I think I can notch the top of the joist since it's supported from below...
 
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Jeff H Young

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A hole or a notch will be ok wont hurt , but might not meet inspector but of cource the studs below will carry that. that joist is only carrying floor load , you could even add a block from the top plate to the sheeting totally unessesary but might make someone feel better. assuming you arent demoeing out the wall below
 

thetoolsmith

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A hole or a notch will be ok wont hurt , but might not meet inspector but of cource the studs below will carry that. that joist is only carrying floor load , you could even add a block from the top plate to the sheeting totally unessesary but might make someone feel better. assuming you arent demoeing out the wall below
Hey Jeff, good point. Not taking the wall out below, can't image anyone ever would. Thanks for the feedback!
 
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