I've got a plumber (who I really trust) coming out tomorrow to temporarily cut into one of my main cast iron waste stacks. Reason: there is a crack in the foundation right behind the stack that is going to be treated tomorrow with epoxy injection -- and the stack is in the way.
Once the crack in the foundation has been treated, the plumber is going to replace the cut-out section of cast iron pipe with PVC.
My worries: the waste stack runs all the way up to the 2nd floor (and out the roof through the attic, so technically through to the 3rd floor). Everything I read says you MUST support the stack when making a cut like this.
I asked my plumber (very reputable company and he has done alot of work in this house for me -- all of which has been good) if he would need to support the pipe before making the cut. He said "no" -- but if when he began to cut he though it needed it, he would support it from below (in the basement, where he'll be cutting).
I am worried about this. It's a beautiful 1930s Tudor-revival era brick & mortar home -- built like a tank -- and I don't want to have all kinds of damage to the plumbing connections in the walls that connect to this waste stack when it gets cut (I hesitated even doing this, but the crack in the foundation is something that appears to have needed attention for a long time -- it gets water, although I've fixed most of that problem from the outside).
Help. What do I tell my plumber? Do I insist that he install a brace? Does it need to be a permanent brace? I can't imagine how tying in PVC w/neoprene gaskets is going to support the weight of this stack. How does this work? Should I be worried -- or trust this guy (who has 40 years of experience in this area, working on these types of homes)?
Thanks for any guidance you can provide!