What’s a “thermal barrier” and when is it needed?

A thermal barrier is a covering on the surface of the spray polyurethane insulation which will protect it for at least 15 minutes in the event of a fire. 1/2-inch gypsum wall board, such as Sheetrock, is an approved 15 minute thermal barrier. Building codes require the installation of a thermal barrier between foam plastics (such as spray polyurethane insulation) and any occupied space. Exceptions apply in some cases; review local codes and/or confer with your local building code officials. The building code provides for an exception to the thermal barrier requirement in attics and crawl spaces where entry is made only for the service of utilities. In such cases, the spray polyurethane insulation must be protected from ignition.