Ground Moisture Barrier | Do you need a building consent?
subfloor - Should I put vapor barrier between sub floor and joists? - Home Improvement Stack Exchange
QuietWalk 100 sq. ft. 36 in. W x 33.3 ft. L x 3 mm T Underlayment w/Sound & Moisture Barrier for Laminate & Wood Floors (30Pk) QW100B1LT - The Home Depot