The first floor bathroom (there is no bathroom on the second floor) is currently being redone; new fixtures and everything. The job is being done by a professional contractor. He is subcontracting the plumbing work and this is where some of the worry begins. Because of the alterations and new fixtures, they will have to attach new pipes to the cast iron main stack . The plumber wants to replace part of the stack with plastic pipes but only from the basement to about half way up in the bathroom. Is it possible to have this plastic tubing underneath the cast iron? We are concerned about he safety and durability (the weight of cast iron) of the whole thing.
Answer:
There are numerous ways to do this but I wonder about the longevity of plastic under cast without the latter being properly braced to support its weight. The other, and just as important, aspect is noise. Right now you can flush a toilet in there and standing outside the door, you hardly hear it. Introduce plastic to the main stack (particularly below the toilet level) and a half block down the street people will hear it.
