I am installing a new bathroom in my home and have true (100 yo house) 2x10 joists with a 12' span and would need to cut three of these joists for the 3" waste. The cuts would be located roughly 18" from one end. Unfortunately I have a stained glass window directly below where the bathroom is to be located and my only option is to cut in order to clear the window and radiator lines.
The joists are located on the first floor. The house is three stories and has a full basement.