We are designing some new residences in Kauai. The roof of the homes are cedar shingles over plywood at a 5:12 pitch. Roof framing is 2 x wood rafters. The roof design does not have traditional attic space and we are placing fiberglass batt insulation within 1” of the underside of the plywood, between the rafters. (Not on the low part of the attic where the ceiling occurs) So there are no vents at eaves or ridges. If we install a radiant heat barrier foil over the rafters before the plywood is placed, is this the correct installation? Would appreciate any insight you may offer.