How should a section of cast iron piping be replaced?

Question

I just discovered a leaking section of cast iron pipe in my basement. There is moisture around the joints, but I guess there could be pinhole-sized spots or a crack on the bit I can't easily see. I'm not sure how long it's been like this but I want to get it dealt with ASAP. I'm looking for some information about the overall process and some ideas about the severity so I can deal with the plumber. Should this be replaced with new cast iron or something else? Will they need to dig up the floor?

The house is 67 years old. This waste pipe appears to be for the upstairs master bathroom based on it's location towards the front of the house.

The only action I've taken is making the bathroom off limits and I have setup a dehumidifier in the basement.

Here are photos

Answer 1

Cast Iron drain pipe with Bell fittings, these are packed with oakum and overlaid with hot poured lead driven in place to seal and then a second layer poured in to complete the seal.

It may only need the lead driven in to repack the oakum and a new layer of lead poured.

Contact a plumber with knowledge about old drain systems, cast iron can take a long time to rust through and may not need replacement.

Answer 2

Moisture pooling in the joints like that suggests standing water in the pipe, which will eventually rust it out for sure. If this is the case, there's probably a blockage of some sort downstream that's resulting in sewage backup (ew). I would definitely address that first. After that, you can decide whether or not it's worth replacing pipe. My guess is that if I'm right, once you fix the blockage, that section of the pipe will be fine for a long time.