Leaky waste line on 3rd floor apt

[Jack Lipomi]

Hello,
I have a situation where the 3rd floor apt toilet cast iron waste line is leaking down vertical in the wall of the 2nd and 1st floors into the basement. The issue would require a complete tear out. We were considering tear up floor around 3rd flr toilet rerouting a PVC waste line through the two floors outside the wall through the floors in the corner of the room. They could they be boxed for aesthetic if desired. Then the thought came to me could you run the waste line out of third floor on outside of house and then into basement to connect up with waste line there? Is that possible or is there a code issue in PA. ?? Comments pls

 

[James Henry]

Aren't you putting the cart before the horse? If your going to do that much demolition to run a drain on the outside why don't you just replace the stack running down inside the walls. I would search for the cause of the leak on the third floor first, unless you've already inspected the stack and found it needs replacing the source of the leak at the third floor toilet may only need minor repairs.

 

[Sponsor]

 

[Reach4]

For all we know, Jack has identified the bad area. But it would be a shame if the leakage was a combo of a drain line that needs rodding combined with a failed wax seal.

I wonder if there is a worry that the outside pipe would freeze.

https://codes.iccsafe.org/content/document/1486
Philadelphia use IPC 2018 with amendments.