Exposed Fastener Rib Roofs: These panels traditionally are manufactured 3 feet wide with a length that is determined by how long the vertical rafters or trusses are. This system should not be installed on a roof deck that has less than a 3/12 pitch. The vertically aligned raised ribs provide channels for water drainage usually every 12” on center. The rib roof panels are attached to the deck with screws that are fastened in between the ribs and on top of all side overlaps. This panel can be installed on residential homes, agricultural, and commercial applications. The decision to re-roof over an existing roof should be made on-site with a professional. There are many benefits to going over an existing roof and at the same time many reasons to take them off. We do both frequently.