Plasti-Fab PlastiSpan insulation board may be used as the insulation component in roof assemblies for either non-combustible or combustible construction. Part 3 of the National Building Code (NBC) of Canada defines requirements for the use of foamed plastic insulation, such as PlastiSpan insulation, in both types of construction. To comply with these requirements, a thermal barrier may be required under PlastiSpan insulation in some cases.

Roof assemblies containing PlastiSpan insulation board are tested for external fire exposure using CAN/ULC-S107-M. The roof assemblies in combination with specific roof coverings are given a rating Class A, B or C based upon severity of the fire exposure. PlastiSpan insulation board has been listed in combination with a wide range of roof coverings.