Venting a combined basement bathroom / laundry room into existing 4″ vent / drain stack
I’ve had a few quotes for installing a new 4 piece combined basement bathroom / laundry room (dryer, shower sink toilet) as apart of getting our basement finished.
Currently the main 4″ stack serves as a combined vent / drain for a 3 piece washroom (2nd story), and as a drain for a (1st story water closet – 2 piece, that is separately vented with a 2″ vent through the roof)
Our hope was to tie the new bathroom / laundry room into the existing 4″ stack without having to run an separate additional 2″ vent. Is this possible? The bathroom will fixtures are all within 10 feet or less of the stack. If venting is need, would running 1 1/2″ branch vents from the fixtures to the 4″ stack suffice?
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