My brother tore out the mdf tile ceiling of his cottage and nailed down ~1x6 pallet wood on top of the ceiling joists in the attic. There are large gaps in the boards. On top of the boards, he rolled some R19 for insulation. This is a summer home only.
His place gets very hot. I am going to recommend he put up radiant barrier in the rafters, but would there be any benefit to rolling up the insulation temporarily and putting a vapor barrier underneath, on top of the pallet wood?