Roof curbs provide a rooftop surface for mounting mechanical or HVAC equipment, as well as rooftop accessories such as air conditioners, fans, skylights, refrigeration units, pipes, and stacks. To provide protection against the weather, roof curbs are equipped with an integral flange.
Special features include thermal insulation, vibration isolation, sound attenuation, adjustable pitch or slope, and heavy-gauge construction.
There are many different types of products. Choices include metal roof curbs, flat curbs, pipe curbs, pitch curbs, and skylight curbs. Curb adapters and expansion joint roof curbs are also available. Metal roof curbs may be installed under or atop a building’s roof panels.
Components include water diverters, polystyrene gaskets, fiberglass insulation, and optional damper shelves. Often, the roof curb framing is made of sections of cold-formed steel. Flashing cells or caps are sometimes used. Metal equipment rails are commonly available. These roof curb accessories feature welded seams and a support-shell made of galvanized steel. Rooftop adapters or curb adapters are also made of galvanized steel, typically from 14- to 18-gauge.
Flat roof curbs have a raised cant to accommodate roof insulation. Models that are equipped with fiberglass insulation provide some sound attenuation. Typically, flat roof curbs are made of aluminum or stainless steel. They are available in a variety of heights and may feature a self-flashing base. Height, inside diameter (ID), and outside diameter (OD) are important dimensional specifications to consider. Damper trays are optional. Like other roof curbs, these products are designed to prevent the ingress of water from rain or snow. Roof curbs include pipe curbs, pitched curbs, and skylight curbs.
Pipe curbs are designed to match the profile of a metal roof. They are made of galvanized steel pipe, and have both a flashing cap and welded collar. The pipe OD is important to consider. As their name suggests, pitch curbs or pitched curbs are designed to be mounted on pitched roofs. Models include peak-mounted and double-pitched styles. Skylight roof curbs come in both loose-clip and cricket styles. They are built to match the roof profile with factory-welded, water-tight, rib pockets. Features may include security bars and enamel coatings.