Closed-cell spray polyurethane foam can insulate and waterproof metal structures for half the price of metal panel replacement in many instances. It adds a number of high-performance attributes to metal structures, roofing and wall cladding assemblies, including: high R-value and moisture controlling thermal insulation, good acoustical performance, reduced uncontrolled air infiltration and exfiltration, great wind uplift resistance, high compressive strength, increased racking strength, and lowered roof surface temperatures.