We used canned spray foam called Great Stuff to seal the gaps in our wall insulation. It’s awesome and fun, and works really well.
We trimmed it with a razor, and touched up the paint on the floor before beginning to lay down insulation.
We first cut sheets of Red Rosin Paper to try and mitigate any moisture that should get in the floor. We’re covering that with R6.5 polyiso foam board. The foil on the foam board should also act as a vapor barrier of sorts. We’ll have the subfloor finished by tomorrow.