DWV size in new bath

[Dr.C]

Hey, great forum!

I am adding a new 2nd floor master bath (shower, vanaties, toilet). It's a 1930's Cape Cod style with a 16" long 2x4 vertical chaseway running from the 2nd floor to the basement. Can I use this space to run all plumbing + DWV through that - i.e., Is 3" sched 30 PVC ok to use as DWV pipe? Or do I need to enlarge that bay to accomodate sched 40. And if I enlarge it, should I just go with 4" pipe?

Thanks!
Pittsburgh PA

[jadnashua]

3" would be a tight fit if you can do your joints outside of the chase. That would be sufficient. But, if there are any nails, etc sticking in that area and you have to expand it, still 3" would be oaky, but you could go up to 4". My unprofessional opinion.