OK, so this is what happens when water leaks from inside the wall.
When we returned from Spain, I sat down to go to the bathroom and noticed a noise that sounded faintly like water running. Not seeing any water, I decided it was probably the toilet tank leaking into the bowl and a new gasket would fix it. I went on my merry way and didn't give it another thought.
A week later, I noticed a small flood on the floor of the room directly below the bathroom (which, incidentally has our main electrical panel in it), dripping from the thankfully open ceiling. My fears were confirmed, there was water leaking from inside the bathroom wall.
After pulling up a bit of the linoleum, we discovered the putrid odor and soft black wood that meant this had been going on slowly for a long time. As an added bonus, I later found that the wax ring under the toilet had long since been distended to the point of leaking a little into the subfloor whenever it was flushed.
So... after a bit of demo, here I am with a rotted subfloor, some sticks and some pipes (fixed now, thankfully). I've had the opportunity to rip out the old crap electrical and re-wire it correctly, and I'm ready to start rebuilding after the subfloor is fixed.
That subfloor needs to come out, and the bathroom will be fully remodeled (I figured as long as I'm doing a bit of demo, might as well do the whole thing up nice )
Does anyone have any tips on how to cut out and replace that subfloor? Should I be concerned about going under the existing wall (not really an option, unfortunately), or should I just sawzall as close to the walls as possible and throw down some 3/4" ply or whatever width is already there? I'm also going to have to sister some more joist material to the joists below, I think, since they're a bit water-damaged and fire-damaged from a previous house fire (thanks for sheetrocking over the top of that one, previous owners )
Does that sound like the right way to do it? I'm pretty good at wiring and I can find my way around most carpentry tasks, but I just want to know I'm proceeding in the right direction before I tackle anything like flooring and support.
I'll be sure to take more pics and update as the bathroom gets remodeled.