The floors are rebar reinforced concrete 6 to 8 inches thick. Where the hardwood was put down, they laid 2x4's on there side and and glued 3/4 plywood to them (not sure why). They spent three weeks running utilities and reinforcing the wall for my wife required giant stone range hood.
Anyway, I was out of town for two weeks and when I returned last Monday they finished laying down the floors (still need to build the steps down to the family room), started staining and installing cabinets, and installed the range hood (still needs grout):
They may finish installing the cabinets this week and actually get the granite in before the holiday. I can't believe how much lighter and airier the kitchen and family room are now that the dark hardwood is gone.