The lifespan of a commercial roof varies significantly based on the materials used, the quality of installation, and ongoing maintenance. For instance, a properly installed TPO or EPDM membrane can last 15-20 years, while built-up roofing (BUR) or modified bitumen systems might serve for 20-25 years. Metal roofing, with regular upkeep, can often exceed 40 years. The primary factors that shorten a roof's life include poor initial installation, lack of routine maintenance, severe weather events, and standing water due to inadequate drainage. Investing in a high-quality commercial roofing system from a reputable contractor is the best way to maximize its service life.