Insulation cover boards are an essential layer of the roof assembly. Overlay boards made of a material, usually under 0.5” thick, that is formed into panels 4 feet x 2, 4 or 8 feet in size and sandwiched over top of the base layer of thermal roof insulation and underneath the roof membrane. Traditionally, cover boards were made out of wood fiber, but recent innovations have introduced a wide array of materials into the market to suit the needs of different membranes and structures. As a general rule, almost all roofs benefit from the use of a cover board, which adds energy-efficiency and protection to your membrane. There are, however, many things to take into consideration regarding your cover board, how to maintain it, and the rare case where it may actually be detrimental to your roof.