We purchased a house with an insufficiently insulated attic. There's currently about 2-3 inches of loose-fill fiberglass insulation in between the 2x6 joists. I'd love to just roll unfaced R-30 fiberglass batts across the joists (simple, no equipment rental, very little mess), but that would leave a 2 to 3 inch air pocket between the bottom of the batts and top of the loose fill insulation. Is this a bad idea?
(We have no current problems with mold, high humidity, etc. I'd rather not create any. I don't understand the physics of this, whether it would cause problems.)