The SecurShield HD Polyiso Insulation is a rigid roof insulation panel composed of a high-density, closed-cell polyisocyanurate foam core laminated to a premium-performance, coated glass fiber-mat facer. It delivers an R-value of 2.5, which is significantly higher than roof cover boards made with other materials such as wood fiber or gypsum. Suitable for both re-roofing and new construction applications, SecurShield HD is specifically designed for use as a cover board over a variety of substrates.