You are installing a second layer of insulation on an attic floor. What is the best way to install this second layer of insulation?

• A. Perpendicular to the first layer
• B. Parallel to the first layer
• C. In the same direction as the joists
• D. Diagonal to the first layer

Answer: (A)

When adding a second insulation layer, install it perpendicular to the first layer. This pattern staggers the joints so they don’t line up, which minimizes air leaks and gaps that can let heat escape. By crossing the seams, the overall coverage is more continuous and the second layer can effectively bridge over the joints of the first layer, improving the attic’s thermal performance. Laying the second layer in the same direction as the first would keep seams aligned and create weak spots, while a diagonal orientation doesn’t specifically target seam coverage and can be less practical to install. So perpendicular placement is the best approach.