This homeowner is adding a enclosed porch with a metal roof to his home. Sprayfoam insulation is the best method for insulating your metal roof, as it helps to keep your home warm in the winter and cool in the summer, and significantly reduce your energy costs. There are many advantages to using sprayfoam insulation versus fibergalss insulation for metal. Sprayfoam provides a seamless air barrier, restricts moisture transmission, adds structural strength, does not shrink or settle and has a higher insulation R value. During humid weather, metal tends to sweat. The moisture will damage the building and can create mold and mildew behind traditional fiberglass insulation.