Sheila writes from Shawnee, Kansas: “My attic already has some shredded paper insulation. I bought faced insulation; do I install paper face down or up?
Install the new insulation with the paper facing down toward the warm-in-winter side. If there is adequate ventilation in the attic you may not need a vapor retarder, and in that case you could freely slash the existing vapor retarder before installing the insulation. You don’t say whether the current insulation fills the cavity between the floor joists but if it does not, you should fill the cavity and place any additional insulation perpendicular to the direction of the joists. You will definitely need to slash the paper facing if you have a second layer.
