Standing seam metal roofing consists of vertical metal panels fastened to the roof deck with their side edges folded together (standing seams) to create a weather-tight connection. This system provides excellent durability, long lifespan (50+ years), and low maintenance. Metal panels are typically 16 to 24 inches wide and run the full length from ridge to eave. Panels are made of steel, aluminum, or copper, each with different performance characteristics and costs. Steel is most economical and durable. Aluminum is lighter and resists corrosion in coastal environments. Copper provides the longest lifespan (100+ years) but is the most expensive. The roof deck is typically plywood or steel with underlayment installed for moisture protection. Metal panels are attached to the deck with concealed fasteners that do not penetrate the upper surface of the panel, providing superior weather resistance. Fasteners may be screws with washers (most common) or clips designed for the specific panel profile. Seaming may be done in the field using a seaming tool that folds and compresses the seam, or panels may come from the factory with seams already formed (requiring only final compression). Roof penetrations (chimneys, vents, skylights) require careful flashing to prevent water leakage. Standing seam roofs have excellent wind resistance due to the strong seam connections. The smooth surface of metal panels allows snow to slide off in cold climates. Maintenance is minimal; periodic inspection ensures fasteners remain tight and sealants remain effective. Metal roofs are fully recyclable at end of life, providing environmental benefits.