cutting into cast iron waste stack

bobprokop · 2007-03-26T00:30:56+00:00

I've got a plumber (who I really trust) coming out tomorrow totemporarily cut into one of my main cast iron waste stacks. Reason:there is a crack in the foundation right behind the stack that isgoing to be treated tomorrow with epoxy injection -- and the stack isin the way.Once the crack in the foundation has been treated, the plumber isgoing 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 (andout the roof through the attic, so technically through to the 3rdfloor). Everything I read says you MUST support the stack when makinga cut like this.I asked my plumber (very reputable company and he has done alot ofwork in this house for me -- all of which has been good) if he wouldneed to support the pipe before making the cut. He said "no" -- but ifwhen he began to cut he though it needed it, he would support it frombelow (in the basement, where he'll be cutting).I am worried about this. It's a beautiful 1930s Tudor-revival erabrick & mortar home -- built like a tank -- and I don't want to haveall kinds of damage to the plumbing connections in the walls thatconnect to this waste stack when it gets cut (I hesitated even doingthis, but the crack in the foundation is something that appears tohave needed attention for a long time -- it gets water, although I'vefixed 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 PVCw/neoprene gaskets is going to support the weight of this stack. Howdoes this work? Should I be worried -- or trust this guy (who has 40years of experience in this area, working on these types of homes)?Thanks for any guidance you can provide!