Transitioning DWV Thinwall to Sch. 40

Can I use thinwall (so that I can use 2 x 4 walls) for venting, and attach Sch. 40 lav / kitchen drains to the thinwall vent/drain, and then transition to Sch. 40 under the crawl space?


Guessing there must be some sort of way to transition these.

Most pipe like SDR-35 or Schedule 30 PVC is not approved for use indoors.

Plumbers run 2" schedule 40 PVC though 2x4 walls all the time.
If you are running a 3 or 4" stack, then you have to frame for it.