Main Drain Connection Failure/Mess (cast iron and clay)

Hello all,

I have a mess and quite the project on my hands here. I am a handy guy but this is outside my comfort zone. I think my comfort zone is gonna expand after this project because i have no option to hire this out...

I am hoping to get some advice and guidance during this research so that I do not make matters worse.
any and all advice is greatly appreciated.

So.... It all started because of this That was the toilet flange. It has been broke for a long time and leaking. So I decided to re-do some flooring and replace the flange. When reinforcing the floor joists, I found this: That is the elbow coming up and out of the main drain. It is cracked out on one side and clay. The whole main is still clay. There is a stack of cast iron Tee's that feed into this. There are a couple different drains that feed into this. Off to the left is the toilet drain that started this wonderful discovery.
To the right of the last photo is the main drain connection further down the line, shown here: As far as I know at the moment this line down to the main drain is ok... It seems that over time the elbow that holds up the IRON has shifted and broke under the weight. I am a little confused as to what is even holding it all up...I am assuming the cast iron t's weigh a lot. Apparently these clay pipes could hold a lot of weight,,,, for 75 years. Anyway, The top "T" reduces down to a vent. This vent is also cast iron and i believe it goes up and out the roof... I am guessing there is a lot of weight on this shifted and cracked out elbow. I have no idea how much. The weight is my biggest concern... as i do not know if modern sewage drain techniques support this type of weight. In all honesty, I do not know much about modern drain designs.... Like I said, I would love to hire this out I just cannot afford it at the moment. Furthermore, there are about 8 other connections like this one under this old place. Better now than ever to learn. Another thing I am trying to keep in mine is the inevitable replacing of the main. Whatever I do now will have to tie in well with future main drain fixes/replacement. A plus is that all of the main connection and piping is relatively shallow and showing in some cases.

Well there is my problem, here is what i have come up with for a solution, thus far:

option 1: Determine if modern "DWV" plumbing techniques can support the cast iron monster. If so, Tie up the iron "T's" to a floor joist. Replace the elbow connection on the main drain side of things. Complete the connections??? (whatever this entails), and loosen the tied up "t's."

This seems like the easiest way to do it.....But i am seeing a lot of pvc stuff being used so i am doubtfull that it will suppurt all the iron weight. But i am not sure on this either.

Option 2:

abandon the cast iron....this will be the hard part because i will have to work top down as i understand these are built from the bottom up....so i would have to pull the 12+ft of vent from the top of the roof, lol, and dissasemble from the top "T" down. and replace from the next best section of main back up.

Option 2 seems like the most thorough and complete repair from a longevity stand point. Seems like the most amount of work also....What are your thoughts guys? I am open to anything at the moment.....

I really appreciate you reading this and any and all help...I am hoping that I will be able to assist someone on this page at some point in return...and maybe the donations to this page will help that also. I am not asking for handouts here.... with any assistance I receive - I will pay it forward. There is some stuff I know, lol, just not this old main drain stuff.

Anyway, I appreciate you and all your help,,

Bryan from Wy.

I would say option 1 except you don't have the PVC support the cast iron. They don't t even allow cast iron to support cast iron.

Provide independent supports for existing CI. Metal straps from floor joist and/or supports from below. Could even use wood supports hung off the joists.

that is kinda what i keep going back to when thinking about this mess...how much do you suppose this might all weigh...i will prob overdue the strapping anyway...there is a joist right above there,,,strapping would be simple enough.

Look up riser clamps. They can be attached to pipe(below a tee branch and such. Then in turn gets supported by any means you have. Like the joists or that column with another support off the ground to attach a cross member.

i see...that will make the job a little easier. None of these concoctions of iron were ever supported under this place... just sit on top of the clay pipe...was this the norm back then?

As far as weight, you could find weight of c.i. pipe and fittings on line.preferably in a manufacturers catalog.
But you start supporting it before you start removing anything that is currently supporting it.

Sorry got to go.

thank you very much....

The UPC does not allow clay under dwellings. Can you see why?

lol, ya i see why. It did however last for 70 plus years tho... I am wondering if this place is the exception tho... i couldn't believe it when i saw all that iron just sitting on the clay pipe... 8 or so other fixtures here the same way ( not broke yet tho) gotta figure this one out before the others do the same.

In 45 years I've see a lot of messed up installations. Never have I seen clay under a house. It can't handle any strain without cracking. It does ok in a supportive bed of soil (base rock preferred). It is a liability to keep any of it.

replacing it all is not really an option at the moment...I just have to get this particular problem fixed at the moment.

What do you do for a living?
Maybe you can find a plumber and trade services with him as a barter deal?

You look young and fit enough to do some kind of labor exchange.
Or a skill exchange.

Or just help marry off his ugly sister, he will owe you forever, haha!

Just kidding, all lady members!

does the vertical pipe just go one story or is this a multi story bldg

No real short term fix. start replacing pipe from the toilet and keep going and support it with wood bracing or use heavy duty straps along with plumbers tape. No weight should be on the pipe transferring to other pipes. I can’t see the pictures but if it’s under the slab you will have to cut and remove concrete to get to the old clay.

Cast iron pipe is what it should be replaced with. But you can use black abs if that is okay with your local codes