My equipment room has insulated walls next to the basement living area, but no insulation on the ceiling where there is a family room. I was planning on putting some fiberglass batts up there, vapor barrier against the floor (hot side). The direct vent/air intact pvc pipes are tucked between rafters. Can I lazily lay fiberglass insulation over them (paper side to them)? The intake would be cold, and exhaust a little bit warm, and there would be lots of dead space.