There is a pipe in my house that has endured extensive corrosion. I have talked with inspectors and plumbers and everyone agrees that something should be done about it. I have had trouble getting a clear answer on a solution I feel confident about.
The pipe is cast iron and around 6" in diameter. It comes out of a concrete wall and into the floor. I believe that it attaches through the concrete wall into my garage where there is a similar diameter pipe that runs from the floor to the ceiling and possibly connects to a bathroom.
The pipe is very difficult to access. It is in a small room and right next to the furnace. There is just enough space for a single person to be able to walk up to the pipe.
I recently had a plumber come and do some other work for me and asked if he could give me a quote for the pipe. After looking at it he said he had no idea how they would replace it but that it would probably require digging into the concrete and potentially having to jack it up.
He also said that it might be possible to repair the pipe. He said that since it was only for drainage and not under pressure that I might be able to clean it up with a wire brush, cover the corrosion in J-B weld, and then cover the whole thing with flex tape.
I know very little about plumbing but I feel I would be able to perform the repair job the plumber described. I'm concerned though that I would only be obscuring the problem or making it worse.
Can anyone shed some light on this issue and help me to understand if the stated repair approach is acceptable? If it is questionable, how should I go about getting it taken care of?