All of the joists needed to be supported and leveled. There's a two-inch height difference between the outer wall and the inner wall where the middle of the house has sunk.

After a couple of weeks redoing the joists, a subfloor finally went down. It may seem like nothing, but can I just say, let the dancing begin - you can jump around and not fall into the basement!
In addition to a new floor under our feet, we now have two new support beams to hold up the ceiling and keep our second floor from bouncing like a trampoline.
Will on a ladder (again - I will have a whole album of shots of Will on a ladder) having just installed another support beam.
Above is a panorama shot of the new beam across the back of the kitchen. It doesn't actually bow out in the middle, that is distortion from the panorama. But the gap on the left and the lack of gap on the right is real. There's a two and a half inch opening on the right and on the left, where our house sinks in the middle, there's no gap. The beam itself is LEVEL.
A non-panorama shot of the beam. Again, the beam is level, it's the rest of the house that is askew.
Above: the gap at the left and lack of gap at the right.
Following are broad shots of all the new support beams. I feel so supported!