Do I need a vapor barrier between the floor joist and the plywood for a new subfloor on a pier and beam foundation?

Summary: Charlie: Mike in Victoria writes, “I’m putting a new subfloor on a pier and beam foundation. Do I need a vapor barrier between the floor joist and the plywood? The house was built back in 1926.”  Tom: Absolutely not. Don’t do that. What I want you to do between the structure and the plywood is […]