How can we help you? Follow Us Frequently Asked Questions WHAT IS A ROOF CURB? A raised frame to provide a surface for mounting mechanical units, skylights, etc on a roof... AND A SELF-FLASHING SKYLIGHT? A curb-mounted skylight is designed to mount on top of an existing flashed roof curb. Consider the skylight curb to be like a shoebox and the curb...-flashing skylight is a skylight that comes with a built in roof curb. The curb is a 4 tall aluminum extrusion that is integrated with the skylight frame. When ordering a self...