Adding Master Bath on shared wall with another upstairs bath

[TommyTwix07]

I am currently in the process of adding a master bathroom on the second floor of my 1927 home. It shares a wall with another 2nd floor upstairs bath. So far i have cut into the cast iron stack and put in the following (see pictures below):

I am wondering if anything here is jumping out at anyone as against code in (hopefully if i'm lucky someone from ohio/summit county will see this)

Current upstairs bath (on opposite side of new master bath):


New Upstairs bath:


Tied into a 4" cast iron stack that runs straight up through the roof (nothing is tied in above the 1 1/2" sink drain-line you see from the bath on the opposite wall)(I secured the 4" cast iron stack with a steel clamp tied into the studs on either side)


My plan is to have a toilet right where you see the flange, then before the flange tie in to the 3x3x2 wye pictured with another 2x2x2 wye (sitting on the floor in line with the installed 3x3x2 wye) take a hubless 45 to the left run 2" pipe ~2' over to a trap for a shower drain, then off the straight end of the 2x2x2 wye run ~8' of 2" pip to a double sink vanity on the other side of the room (roughly behind the perspective of the picture above) then vent with a mechanical valve or run a vent up into the attic and tie back into the cast iron stack (ugg really don't want to do...)

Before i drill a permanent 2.5" hole in my 10" joist for the shower drain (i know at least 2" away from the top of the joist...) I would like to know:

-Does my plan sound correct?
-Anything jump out at anyone that screams CODE VIOLATION?

Thanks for your interest and help!

[Terry]

The shower should be vented "before" it wyes into the toilet waste.

The lav will need a vent.

With a toilet that uses a 3" flush valve, flushing one toilet will lower the water in the opposing bowl.
A better method would have been to install a wye in the wall below and have seperate santees for the toilets.



Below

[hj]

Here, using the sanitary cross, with or without the cleanout, would be a code violation. But, as long as you were using it, you might have used a 2" side inlet cross and connected the tub/shower and sink into it instead of the closet "bend". it looks like you are going to have about a 15" or 16" toilet rough in the way you are doing it.

[TommyTwix07]

The wall below is plaster and lathe and has stone veneer on one wall and plaster molding on the other. Accessing the stack in the wall beneath isn't a good option unfortunately. Plus there isn't enough room from one side of the stud bay holding the stack to the other to get another 3" drain lower without going to the joist bay to the right, which would put the flange too close to the exterior wall to fit properly. My main concern is whether it would pass code (even if it were in your region). I can live with the water level going down slightly.

[Terry]

Well..............you were warned.

I don't know anyplace that a double santee would be allowed for back to back toilets.

Just so you know, my home has a double "fixture" fitting in the same location. And I lose quit a git of water in the bowls.
Making that a double "santee" would be even worse. My next project is to open the walls up and change it to individual santees.

[TommyTwix07]

Okay thanks guys!! I really appreciate the advice. I will see if I can come up with a path down to the basement (which also has finished ceilings, ugg...)