Hello. The majority of the 60+ year old insulation in my attic is compressed and very dusty/dirty. I doubt it has much R value.
I live in the midwest. In the summer it can get above 100 degrees with a lot of humidity. The winters drop below zero.
I would like to remove the existing faced-bats and replace with blown in fiberglass. My question is whether I need some type of vapor/air barrier/retardant laid down on the attic-side of the ceiling before I blow in the fiberglass.
Thanks for the advice.