Most residential roofs in the United States are composition (asphalt) shingle, and most roofers work primarily in that system. Specialty roofing covers everything else: natural slate, copper and other metal panels, clay and concrete tile, and modern green/cool roof assemblies. Each behaves differently, fails differently, and demands installation technique that does not transfer cleanly from asphalt work.
Slate and clay tile are heavy, brittle, and long-lived — a correctly installed slate roof can outlast the building — but they punish inexperience, and a contractor who rarely works in slate can crack or mislay it. Copper and standing-seam metal require sheet-metal skill and careful detailing at flashings and seams. Green and cool roofs add waterproofing, drainage, and load considerations that overlap with other trades.
Because of this, the right question is not just “are you a roofer?” but “do you regularly install this specific system?” A C-39 licensed contractor is authorized for all roofing materials, but day-to-day specialty experience is what protects an expensive slate or copper roof.
Contractor Intel uses AI to extract each contractor’s actual specialty mix from their public footprint — slate, copper, clay tile, metal, green/cool — and tags listings accordingly, so a homeowner searching for a Bay Area slate roofing specialist sees contractors who genuinely work in slate, not every roofer in the city.
When hiring for a specialty roof, confirm the C-39 license, then ask for recent projects in the same material and, ideally, the manufacturer or material certifications relevant to that system.