My toilet leaked into the basement and the arm of the stack sits on 2 floor joists. The basement is finished but I took down a few tiles in that area. The plumber came and put two new wax rings on (since they had squirted out from under the flange? And filled a gap in the front of the ring as well. It was good for about a week and is now leaking again. I had found a piece of cast iron collar on the top of the ceiling tile when I took it off and showed it to the plumber. He thought it would still be okay because it was a piece high enough up on the stack. If I do need to replace that part of the stack (cast iron) will the floor need to be torn up in that area? Should I go with PVC for the new waste line? I live in the Chicago area - anyone know how much this will cost me?

Thanks ~
ACM

Stacked bowl waxes will never guarantee a reliable water - tight, odor - proof, or germ free seal, and any plumber who stacks wax is not paying attention to his main responsibility , and that is to provide sanitation.
Stacked wax gaskets are prone to failure due to shrinkage, probing by a snake or auger, and water erosion - a properly installed wax ring will never get wet, unless there is a blockage in the pipe it is connected to.
Stacked gaskets will also fail under the slight pressure created when the toilet bowl fills up and overflows due to a pipe blockage...

No idea on cost and no idea what is involved without being able to see the job. I suggest that you call a few local plumbers and discuss options/estimates of cost with them. In this way, you can make a well-informed decision... ;)

Mark