DuraBoard roof insulation from Johns Manville, Denver, can be used in both SBS and APP roof system installations and is heat-weldable for these membranes. The insulation, which is available in 1/2-, 3/4- and 1-inch thicknesses, also is impact-resistant and has high wind uplift ratings. Because of its weight-bearing strength and rigidity, the 1-inch DuraBoard can be used to span the wider rib openings of metal roof decks.