Working knowledge of all commercial roof systems and their details: single-ply (TPO, PVC, EPDM), modified bitumen, built-up, metal (standing seam and exposed-fastener), steep-slope (asphalt shingle, tile, slate, metal), spray polyurethane foam, and fluid-applied coatings; tapered insulation, flashings, edge metal, coping, drains, curbs, penetrations, and expansion joints. Perform complete quantity take-offs from construction drawings, specifications, aerial measurement reports, and field measurements, including roof area, slope, perimeter and flashing linear footage, penetrations, drains and scuppers, curbs, insulation and tapered systems, wood blocking, and edge metal.