When putting in new insulation in attic floor using fiberglass batts should I buy the paperfaced and have the paper facing towards the house side? I live in Long Island NY so so the winters can get cold here. Should the fiberglass extend past the top of the floor joists or should it be flush? What about Roxul can I use that? It dosent come with paper on it? Would that be ok to just put down between the joists? Or do I need to put down some kind of air barrier under neath it?