Most commercial buildings in this city don’t have metal covering the entire roof field. What they do have is metal throughout the roof’s critical details, and that distinction is the entire point of this page. Almost every one of them has metal somewhere on the roof, and that distinction is the entire point of this page.

Parapet coping and edge metal cap the top of a wall or the perimeter of a roof, exactly where wind, water, and thermal movement all concentrate at once. Counterflashing protects the upper edge of base flashing at walls and other transitions, while properly detailed flashing around curbs and penetrations keeps water from working into the roof assembly.

Gutters, leaders, and scuppers move water off the roof once it gets there, and a system nobody’s cleared in years is often the actual cause of a problem that looks like a roof leak but isn’t.

Mansards, bulkheads, penthouses, and canopies are the steep-slope elements sitting on top of an otherwise low-slope building. Older New York buildings often carry these in a profile nobody makes as a stock item anymore. 

Equipment screens and roof-level enclosures round out the list, metal work that has nothing to do with weathertightness directly but still needs to be built and fitted correctly around everything else up there.