This document discusses various roofing systems for low and steep slope roofs. For low slope roofs, it describes disadvantages like slow drainage and standing water issues. It also discusses advantages like covering large buildings. Components like decking, insulation, vapor retarders, membranes, and flashings are outlined. Steep slope roofs drain quickly and use small overlapping materials like shingles, tiles, and metal panels. Insulation and vapor retarders are typically below the deck, and different roofing materials like wood, asphalt, slate and tile shingles are summarized.