My attic space is currently filled with 6" of blown-in cellulose, and framed with 2x8 joists on 16" centers. I would like to add flooring to a portion of this space for storage after blowing in additional insulation.
Would it be acceptable/advisable to run 2x4s at 90º angles to the existing joists allowing me 12" of insulation, then to use 7/16" OSB over those to provide a solid area for storage? Would some kind of vapor barrier (or paint on the OSB) also be needed?
The installation is in Atlanta, GA and the 1500SF attic will be well ventilated with 48' of rigid ridge vent (and soffit vents to exceed the ridge vent balance requirements)