In March 2000, HUD issued a proposed waiver concerning condensation control for exterior walls of manufactured homes sited in humid climates. This proposed waiver would permit the optional placement of the vapor retarder on the outside of exterior wall insulation in hot, humid climate regions with the provision that the interior wall board and finish must attain a combined perm rating of 3.0 of greater. MHRA collected samples of wall constructions from manufacturers and coordinated a series of test, applying the ASTM E96-95 protocols, to measure perm ratings for wall systems of manufactured homes currently in use in hot and humid climates.