A pre-manufactured self-flashed curb assembly for rooftop daylighting systems is provided. The curb assembly includes a curb defining a clear opening therein of predetermined dimensions for use in attachment to roof trusses having common and standard inter-spacing. The curb includes beams having at least two apertures therethrough for receipt of roof attachment fasteners. Also included is a flashing skirt carried by the outside perimeter of the rectangular curb, for a complete, water-tight assembly.