Here is how the building looked yesterday from the second floor looking down into the basement. You can see where the old steps were on the right where the handrail still is bolted to the wall. The joists in this part of the building were in terrible shape, so we tore them out and replaced them with i-joists, which are stronger and can span greater distances without posts.
Here is the new framing from today. The new i-joists are so much stronger than the old lumber and 100% level.
In the basement, we dug a test pit to locate the old plumbing. This is necessary because we'll be digging down about a foot in the basement, and we needed to make sure that the level of the plumbing was beneath where the new floor will be. We found that we have enough clearance, which is fortunate.