Adding full bathroom to attic
I'm a plumbing novice, though I can do all the finish stuff. Never done the work behind the walls. Last year we bought a house built in 1925. The third floor walk-up attic is in excellent shape. I plan to finish it this summer.
I can see the (probably cast iron) vent pipe coming up in the rafters and through the roof. I'm pretty sure I'd have pretty good access to that pipe (and maybe the hot/cold lines as well) because the second floor bathroom wall backs up to my closet. I'm not really sure what I'm supposed to do.
A cursory search for "how-to" videos seems to indicate that I need to cut a segment out of that vent pipe and add a split onto it so the attic toilet, shower, and sink would all drain there. Then I would need to find the hot an cold lines and also add splits onto them so I could run lines up to the attic.
Questions:
1) Is the vent pipe I see in my attic also the main drain line I tap into for attic toilet, shower, and sink?
2) Do I split the hot/cold lines from current plumbing into a single hot and a single cold line going to the attic and from there split it off for the shower, faucet, and toilet?
3) Am I missing other major steps in this process?
Thanks everyone!