Roof designers and contractors should be aware of when and why we use coverboards.
Double-layered insulation is also more preferable over metal decks, which account for the majority of roof substrates in the United States. Applying a cover board over mechanically attached insulation offers three distinct advantages. First, it reduces the shank length of the fastener by as much as one-half of the total insulation thickness. The fastener is only required to penetrate through the bottom layer of the insulation. The cover board is adhered using hot asphalt or a specially formulated adhesive that is applied over the top surface of the bottom layer of insulation.