moisture barrier ???
I don't think I agree with Bob on his sealed skirt idea. Generally you want some kind on membrane over the well draining soil, a vapor barrier/insulation between the joists, or foam, and plenty of cross ventilation.
The specifics are determined by location and soil type however. What should be done in your case may be different from a home 100 miles away, and certainly different from what I should do here in the north half of the country.
You should consult someone that would be considered an expert, (not someone at the big box stores). A reputable insulation company or maybe start with your town's building department.
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