I want to insulate my 2 1/2 car garage attic,the only thing is the ceiling drywall is nailed to 2x4's.I want to put a r-38 up there.I know it will be above the 2x4's but I won't be putting any thing up there to compact the insulation.Would that be ok,if not any suggestions.I do live in the south so winters are very mild.