ABS to Wall Hung Toilet through a Floor Joist?

[thetoolsmith]

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.

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.


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

Any tips or feedback would be greatly appreciated.

Thanks!

 

[breplum]

A 3" tee would be the proper fitting (not a combo) but you need to properly vent with a 2" branch nearby with a rolled wye or ....even have a vertical 3 x 2 wye in the wall below.
We never use plastic pipe above an occupied space for sound annoyance reasons. Cast iron is much quieter.

 

[thetoolsmith]

A 3" tee would be the proper fitting (not a combo) but you need to properly vent with a 2" branch nearby with a rolled wye or ....even have a vertical 3 x 2 wye in the wall below.
We never use plastic pipe above an occupied space for sound annoyance reasons. Cast iron is much quieter.

Thanks, with a 3" tee that'll put my 90 closer to the top of the joist. If so I'll need to notch the top of the joist but maybe that makes more sense because it's supported by the wall below...

 

[breplum]

I'm not sure that there will be enough room on the top of the tee for a bushing and a 2" street 90 (for a vent). The better choice is perhaps just regular 90 rotated.

 

[thetoolsmith]

I'm not sure that there will be enough room on the top of the tee for a bushing and a 2" street 90 (for a vent). The better choice is perhaps just regular 90 rotated.

Is a new vent required if I already have an existing vent for the old WC? (red arrow shows current vent pipe)

 

[breplum]

That would not be a vent, being upstream. I'd be open to someone arguing it as a horizontal wet vent, but not to my knowledge.