Replacing Cast Iron Stack> 3" or 4"?
Posted by ed breyer on October 02, 2001 at 14:33:36:
I'm replacing my cast iron stack and all related plumbing and vent lines. The cast iron stack is 4". According to a contractor I know as well as plumbing reference books - 3" PVC can accomodate the number of fixture "units" I have. However, I'm wondering if I should run 4" PVC. Obviously 3" gives me more room in the tight places - but I want to do it right.

I'm thinking of running 3" down from the upstairs bath and transitioning to 4" as it pick's up the downstairs bath and kitchen (& ties into the 4" cast iron). Thoughts?

Also> What's the best way to sound insulate the PVC stack - loosely OR tightly packed fiberglass insulation in the stud cavity? Are there any alternatives materials/methods specifically designed for deadening the sound of PVC stacks?

Thanks!


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