First, they had to clear a little space around the perimeter so that they could add the styrafoam insulation.
Meanwhile, they started putting the sill on top of the blocks (with a plastic foam pad under it).
The sill is held in place by straps embedded in the concrete.
The crawlspace walls are insulated with 1" of styrafoam.
The center beam is a 3"x10" chunk of Oriented Strand Board (OSB).
The joists are manufactured from 3/4" OSB and 2x3s.
The subfloor is good old-fashioned tongue and groove 3/4" plywood.
These guys have liquid nails that work in sub-freezing weather.
And they will be back on December 12 to put up the walls.