The 1.5-inch panel is a composite material consisting of three primary layers:
: A 1-inch thick layer of polyisocyanurate (polyiso) foam bonded to the back of the OSB. 1.5.zip
The 1.5-inch variant is often the minimum thickness required in the ZIP-R product line to satisfy energy codes in colder climates. However, designers must account for specific regional requirements: Roxul Comfortboard - disadvantages? - GreenBuildingAdvisor 1.5.zip