Which statement best describes the orientation for a second attic insulation layer?

• A. Perpendicular to the first layer
• B. Parallel to the first layer
• C. Along the joists
• D. In a diagonal pattern

Answer: (A)

When adding a second layer of attic insulation, you want to cover the joints of the first layer and prevent heat paths from lining up. Placing the new layer perpendicular to the first achieves this by staggering the seams, so there aren’t continuous gaps through both layers. This arrangement reduces thermal bridging and improves the overall insulating performance more effectively than laying the second layer in the same direction or in patterns that align joints. A parallel layout keeps the joints lined up, which can create gaps, while diagonal or other nonstandard patterns don’t specifically target seam coverage between layers. So, orienting the second layer perpendicular to the first gives the best, most reliable boost in insulation.