Metal tile on 2.5:12 roof

Most metal tiles and shingles require a 3:12 or 4:12 pitch. Under no circumstances, even with a "beefed up underlayment" (which so many people have attempted) should any roofing material ever be used on a roof pitch lower than recommended by its manufacturer. There are many metal roofs that can be used on 2.5:12 but they will be vertical seam roofs. In some cases, projects will have metal tile or shingles on the steeper roof portions and vertical seam on the low pitch areas, for accent.