Frank writes from Woodstock, Illinois: "I want to increase the insulation in my attic to meet US government EnergyStar recommended R-values. I currently have fiberglass batts between the joists. A makeshift floor of 1/4" plywood has been overlaid and secured to the joists in some sections of the attic in order to facilitate movement and storage. When adding new fiberglass batts, do I need to remove the plywood "flooring" or can I lay the new insulation directly atop the plywood?"

Answer: If the insulation fills the joist, then unfaced insulation can be placed on top of the plywood flooring. If not, the new insulation will not be as effective.