Bathroom plumbing

[carlos mejia]

I want to add a bathroom in the second floor
There is a stack (cast iron) sewer line 4" that runs from the basement and comes out to the roof.
could I tie in into the stack with a 4" 4 way sanitary tee?

I will use the the 4" to the toilet, the opposite opening to drain the shower and sink and the up and down opening to continue on to the roof.

There is currently a full bathroom in the basement and in the main floor already

 

[Tuttles Revenge]

Very likely that stack is the vent from the plumbing on the floors below. It shouldn't be used as a drain stack. The proper way to connect is below the point where the vents connect.