Multiple vent stacks or just one?

[billly]

I have a set of basement fixtures which are served by a vent which routes horizontally in the joist space between basement and first floor before going vertical. I'm doing a kitchen remodel and need to reroute the kitchen sink vent. I'm wondering if I can tie into the stack from the basement fixtures once it's 6" or more above the flood plane of the kitchen sink, or if I need to put in an independent stack for the kitchen.

Thanks!

 

[Tuttles Revenge]

Your vent serving the basement can connect to your main floor venting as you described. The cross sectional area of the required building sewer still has to be met by the same cross sectional area of the total vents leaving the building. So if the kitchen vent were to have been run individually out of the roof to meet the cross sectional area of venting, then that would need to be mitigated somehow. However, most homes in seattle typically have a 4" cast iron stack exiting the roof. If you have that then no worries.