Cast iron to ABS plumbing stack conversion

[Jona77]

Hey guys,

Been doing lots of reading but this is my first time posting.. I have a basement I'm doing some renos on and I find the current cast iron plumbing stack to be convoluted and imposing. I am hoping to move it closer to the wall and replace it with ABS. I've attached some pictures of the current setup and also a paint diagram I made of a potential new system. If anyone wants to look it over and give me any tips or let me know if i'm way off or if it could work as is or with some changes please let me know!

Notes: Although it's not shown in the diagram please assume everything is properly vented. Also there is a 2nd roof vent above the kitchen so I'm not too worried about the sump pump discharge creating suction on the sink P trap.
The bathtub P-trap is the one under the joists with the drain pipe going under the joists. I would like to put it toward the foundation wall and along side the long copper kitchen drain and black plastic sump pump drain.(converted to ABS)
The rest should be intuitive but any questions let me know!

Side questions:
1. If I can find a way to secure the roof vent portion of the current stack above the basement do I have to replace it? Or can I leave it cast iron? Any tips on securing it?
2. Does anyone know what kind of pipe that is flexible black plastic stuff is and if there's ABS adapters for it?
3. The vent pipe is sandwiched between two very close joists as you can see in the pictures and there's a fitting directly at the underside of the joists.. If I can't easily access this from the bathroom above is there another way to tie in the ABS pipe to the vent without overhauling the joist area or replacing the whole vent pipe? Would it be a difficult to desolder that large fitting to give me space to attach a flexible coupling?

Any help appreciated!

My rough plan (I'm not a plumber)

IMGUR LINK https://imgur.com/a/cpE1z5l

 

[Reach4]

1. Yes. Riser clamps may be helpful for that.
2. That is probably SIDR polyethylene pipe that connects with barbed "insert" connections.
3.?

You are not supposed to use a sanitary tee carrying sewage in the side port except where the side port is horizontal. You should use a combo (combination wye +45).

Don't take inference from what I did not comment on. I am not a plumber. There are many aspects I don't know.

 

[Sponsor]

 

[Jona77]

1. Yes. Riser clamps may be helpful for that.
2. That is probably SIDR polyethylene pipe that connects with barbed "insert" connections.
3.?

You are not supposed to use a sanitary tee carrying sewage in the side port except where the side port is horizontal. You should use a combo (combination wye +45).

Don't take inference from what I did not comment on. I am not a plumber. There are many aspects I don't know.

Hi!

Thanks for the reply. I worded question 1 weirdly and not sure which part your yes refers to! Yes I have to replace it? or Yes leaving it cast iron is OK provided it's riser clamped on the above floor and in the attic? (bungalow)

Thanks for the tip on the combo at the bottom, I googled it and you're totally right!

 

[Reach4]

1. If I can find a way to secure the roof vent portion of the current stack above the basement do I have to replace it? Or can I leave it cast iron? Any tips on securing it?

Sorry, I misread. You do not have to replace it. Secure it before cutting stuff below that may help holding stuff up. The riser clamps can be useful for grabbing the pipe, an letting you support pipe.