Basement planning help: toilet and shower

[fieldingdots]

I'm in the early stages of figuring out how to add a toilet and shower in my basement. There is already a washer, dryer and utility sink in place. They are plumbed to a 2" drain line and vent stack. There is a kitchen sink directly above.

The existing 4" stack is C.I. and located opposite in an existing basement garage, also the pipe is too high to easily connect to on the inside. I am thinking of draining the toilet and shower to the exterior, and connecting a few feet above an existing valve access cover to the exterior PVC drain line. I am converting a basement garage into a livable space, so the drain pipe can be easily routed through what was the garage door opening.

Can I use the existing vent stack to wet vent the toilet and shower?
I believe I need a clean out for the new connection. Would it be better to tie in slightly downstream from the existing valve cover?

Any issues with this plan or better recommendations?

Once I figure out this rough approach, I plan to do the rough in drawings for the plumbing.

Thanks in advance!

 

[Jeff H Young]

normally there arent 4 inch vent pipes coming through basement floor ? so if you are sure thats a vent stack and not a drain stack i guess you are good

 

[Sponsor]

 

[Reach4]

Under UPC, I am thinking the shower must be vented, because the toilet cannot wet-vent the shower.