Specifying insulation that extends a roof system's performance life is essential, but it is only one factor maintenance and engineering managers must consider. When managers select a roof insulation, they also must account for the building's thermal needs, satisfy applicable energy codes, and deliver a roof assembly acceptable to the facility's insurance carrier.

To perform successfully, insulation has to become an integral part of the roof assembly and must function in concert with the membrane and the structural deck. Wise insulation choices result in successful roof systems that perform over the long term, while poor choices can be detrimental to roof performance.

A variety of rigid insulation types are available to managers, including wood fiber, perlite, polyisocyanurate, expanded or extruded polystyrene, cellular glass, and gypsum board.