I was hoping to simply replace a few fixtures in a basement bathroom and have found some issues that make putting things back like they were nearly impossible. This was a terrible DIY bathroom project from the 1980s and I can't justify the money to fix it with any kind of minor fix, it's a mess. Leaving it alone was no longer an option after a leak.
I am beginning to cost out a complete remodel for the basement bathroom and maybe the upstairs bathroom directly above whil I have the ceiling down. I have a cast iron stack and drain line below the slab. I have had the clay line outside replaced to the street previously. I was told the inside line looked to be in good shape when that was replaced. There is about 4 ft of the drain line that will need accessed for the remodel, near the connection to the stack. Then there is 20 ft to the outside line. I realize this depends on local codes, but will I likely need to replace the entire line under the floor if I access any part of it? Is there a code approved sleeving option?
If I do replace the entire line, is there a way to connect to the pvc outside without excavating outside the footing again? I think there was about 1 ft of cast iron that projected outside.
Will I also be required to (or should I) replace the entire stack? This would likely no be too hard depending how the vents tie in. All of the plumbing is accessible from the basement and I think all the vents tie in in the attic.

you will have to dig down to the PVC outside to attach to it.
i would attach a "Y" onto it with a street 45 in it so the branch looks up to the sky. then extend that with a short piece of pipe up to a cleanout at the dirt level. tie the house drains into the back of the "Y"..
there is no code dictating how much or how little underfloor pipe you must replace.

Thanks. Clean-outs were installed with the lateral replacement (two clean-outs to snake each direction) so that is all good, just no good way to replace inside the house without excavating again outside the house. It is only about 5 ft down, so I can likely dig that by hand, just was hoping for a way to do it from the inside. But, If I can simply fix it back at the bathroom and leave the rest, (even for just a few more years) that will certainly be the easiest.

Can I replace just the bottom section of stack, or will this need to be all done at once? It it the bell fitting cast iron type, so not sure that can rest on top of a pvc section.



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you can always leave the short section of cast iron going thru the foundation. cut it inside and join onto it there.
you can replace the stack starting at the bottom and go up as high as you want (or dare)..
just get a good brace under one of the hubs to keep the top part from sinking down when the lower section/s are removed.
a riser clamp will support the weight just fine.
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Thanks, it seems that this should be fairly straightforward then, just a bit more expensive than I thought. I may do the upstairs at the same time and replace the entire stack, that's not a deal breaker, just don't want to tear up another room to replace the sub slab drain until necessary. Glad it seems there are limits on "if you touch it, everything needs to come up to code". It seems a bit odd to have a new section, old section, then new lateral to the main, but if it's working, I can save that for another year.