thanks Nealtw, (sort of ) Added Pix at bottom of this. This started with a burst shower head, progressed to tiling the shower wall, then all the fixture walls, and finally to the floor too.
Going for the floor is the killer. Aside from all the rest, I found the long exterior wall's subfloor ends were not fastened/resting on their ends (leaving about 8" unsupported) -- enter the effort of repairing that, which led to sistering, exposing the rest of the joists and then the drain area.
Each time i took the next leap of scope I thought 'this is gonna end up a complete reno....'
A note: that short joist running perpendicular to the others to the left of the flange is cut fully to allow for the drain.
the chase for the stack runs in a bulkhead down a kitchen wall. 11' ceilings there so a dropped bulkhead below the toilet to the stack is do-able - but aesthetically not so sure.
The bathroom sits atop the kitchen -- but the kitchen extends out beyond the (as yet) untouched exterior wall (a post original construction addition) -- and probably explains the lack of support for the sub-floor along that line. There is a 2" vertical gap between the header joists there and the "hanging" sub-floor.
By "repair and reframe" do you mean the drain(s) area? -- or _all_ wood: non-load studs, ancient joists throughout & exposing both ends of the ancient joists? Which means invading the kitchen below and likely the hallway outside the b-room door?
The "old" floor was 3/4 hardwood over 1" t&g. Finished I'd expected 3/8" tile w/ ~1/4" mortar over 1/2" (concrete) board over 3/4" plywood. That's durn near close to the original -- swapping the 3/4" ply for 2 sheets of 1/2" isn't bad, though the 3/4" i got already will need returning. aaarghh.
I don't mind the cost of learning, but material waste kills me.
I'm not sure, no, I don't follow, your cheater method. I'm ambitious -but ignorant. The cheater method seems like what I'd thought of with sistering (the brother post: http://www.houserepairtalk.com/f32/leveling-bracing-issues-120-yo-joists-17798/) You're saying beef up the kitchen wall with 1/2" ply? and the wall "plates" are what I'm calling rim joists?
I haven't removed all the subfloor. Only the 3' feet in from the window (exposing the lead drain). I stopped because of the likelihood of wasting more time trying to prep for the plywood when it seemed likely it was heading for "repair and reframe" and/or I want to get a plumber in to rip out that lead.
sorry the pictures are all I got right now. I'm not there right now. the room is ~12 x7'. the drain chase joist is about about 20" across, 8" on the opposite wall, then there are 3 (or 4?), all vary around 16oc.
obviously, the dims below are feet not inches -- unfamiliar software
thanks so much!