Joseph writes from Lynnfield, Massachusetts: "Looking to upgrade attic insulation. Current insulation has vapor barrier facing up - 3.5"/16 on ctr 8" deep. Should I remove existing insulation? What is the recommendation between R30C and R30. I have been informed to remove existing and install new insulation with barrier facing living are."

Answer: We recommend that the insulation be flipped over. Leaving it the way it is could lead to condensation collecting in the fiberglass insulation and damaging the surrounding framing. R30C is thinner than standard R30. It is used in cathedral ceilings, or were space is limited.