Ok I have some major concerns now.
When I took out the brass insert in the waste stack to replace with a 4" rubber bushing + 4x3 flush bush.......I noticed that the existing non-notched piece of floor joist was cracked and it literally just broke in two in my hand. Also the toilet flange was not soldered or leaded it- it was just press fit in as it popped right off when I went to pull it to try and jiggle the DWV connection.
There was no oakum in the DWV connection.
You can see this in the pics.
The idiots who did this notched the HELL out of the joist as Jadnashua pointed out.....and I have a feeling this is not going to be good for me.
I can see that they notched out the adjacent 4-5 joists for the 1.5" copper drain for the bathtub instead of drilling holes......
I'm leaning towards replacing the entire cast iron waste stack and going to PVC. I don't think I can support the notched beams good enough and it seems to me it's right in the middle third of the joists. There's no way to "fix" the upstairs toilet connection to the CI stack as it's right at the joist.
If I replace the entire stack with pvc, I think that will allow me to do the following:
1) Sister the super notched out joists and install solid 2x6 to connect the sistered joists together.
2) Flip the orientation of the bathtub upstairs to having the drain at the outside wall instead of where it is now. I would go from a right drain to a left drain. For some reason the Americast Cambridge is $100 cheaper at $399 on build.com for the left drain. I don't get it.
I can run a drain from the sink and make two 90s, drill proper holes through the joists, and run new water connections and still go up into the ceiling and reconnect to the stack for venting.
3) The downstairs bathroom joists are also compromised. I just went down there and saw a severely cracked joist I did not see before.
4) I want to install a manifold system as currently everything is connected serially. If anyone turns on any faucet during a shower or flushes a toilet, massive drop in flow.
5) Possibly convert everything to pex. Currently I have copper at the water main, transition to pex to the tankless hotwater heater, and tehn to brass and back to copper at the kitchen and bathrooms.
Of course, this entails ripping out the downstairs bathroom and moving my family out for a while as we won't have a toilet.
I wonder if insurance would cover some of this cost? I have documented everything in this thread as well as with pictures of the initial toilet leaking waste.