I have a cast iron pipe, about 5" diameter, that runs from the second story bathroom and then across the floor between the beams of the first floor, and then down into the sub basement. I have ripped out the plaster/drywall in the celing of the basement room where the best access is. I can see that when there is water comming from upstairs it leaks one drop per 5 seconds or so.

Anyway, this is something I will have to fix myself. I would like to know what experianced people think about the following.

How to cut the bad section out. Can I use a reciprocating saw? There is limited clearace to work with, but I think the sawzall will fit in there.

Also, can this be replaced with PVC? I would think so, but I want to be sure about what I'm doing.

I read and saw on an episode of This Old House where a rubber coupler with hose clamps were used, is this the best way to go? On the show the pipe was replaced with another new piece of cast iron pipe and he used a large expensive chain tool that cut the pipe.

Is there anything else I need to consider to do this job?

Thank you,