Ok, I'm starting to scratch my head. Before I do anything...
on the 2x6 14ft span, I had my girlfriend jump, and there was a noticeable flex in the ceiling. She was too scared of jumping on the 16ft span (the one with bedrooms, and a wall divides the two rooms going down the midspan of the 2nd floor), so I went and jumped...and the floors were extremely, extremely solid. This made no sense to me: how could a 16ft span with a wall in the middle of it, be so much more solid than a 14ft span?
So this got me doing some more locating with my stud finder (except locating the ceiling joists/2nd floor floor joists). I think I marked 4 or 5 ceiling joists, until I got about 3ft from the exterior wall that runs parallel...then I found no more joists...but, for some reason...the joists started running the other direction? What the hell?
So I found a hole in the ceiling near the midspan, where a piece of coax cable was running. I chiseled it out into a square big enough to get my camera in there. Unfortunately, everything is so close together that it's hard to see what exactly I'm looking at. One thing for sure: that 2x6 may not be a 2x6 after all:
And yes I know it's a horrible drawing. The wall in ? is the wall this thread started asking about. The wall on the right is the front exterior. And yes if my stud finder isn't retarded, it's showing the joists are laid out like this. All in one room's ceiling.
Anyways...near the hole I made is a piece of wood, that appears to be toenailed between joists. I don't know what the purpose of it is. Perhaps to attach drywall, or maybe it was actually intended to act as a support?
Here's a pic of the piece of wood, attaching to the next joist away from the wall in question. Also, notice the "floor" above it...except this isn't the hardwood floor that's in the bedroom. This has to be under the wall that divides the two 2nd floor bedrooms...and it appears to be sawn lumber?
And now, facing the wall in question.
Also, a pic of the original studs that go up the wall. You can see the newer, lighter sticks in the background, mostly blocked by whatever is blocking that span (some sort of paper).
So now, I don't even know what the hell to think. Perhaps I should just rip down the entire ceiling to see for sure. It's hard figuring things out with closeup pics barely accessible by a camera. And if my stud finder is picking up more smaller pieces of wood, perhaps the joists aren't entirely laid out as I though. But this is weird. SOMETHING has to be supporting that floor so well. I even went up into the attic. I could start to see a gap in the 2nd floor wall, but then as I progress out towards the exterior front wall, the top of the wall become closed off with a solid piece of wood.
Hopefully this makes sense to someone, because I feel I'm spouting off a bunch of crap that makes no sense :\ Someone please post with your thoughts...thanks.