How To Set A Roof Curb

Specify prefab roof curbs for use with all roof penetrations and roof mounted equipment including and not limited to hvac units duct openings pipe penetrations power roof exhauster intake and relief vents flues or job fabricated items.

How to set a roof curb. The opening through the metal roof was for the intake duct to the a c unit. Roof curbs allow the installation of the primary roof and the flashings around this roof curb prior to the delivery of the actual roof equipment and the setting of this equipment. After leveling the curb we anchored the curb down with 4 screws to the metal sub roof. Curb installation should be a part of the roof deck not on top of insulation or roofing materials.

Because the roof is slightly slanted one side of the curb had to leveled with boards. Specify prefabricated roof curbs and related products by a roof curb manufacturer not with or by the equipment manufacturer. Prior to setting the unit onto the curb the installer should ensure that a sealing material is positioned between the unit and the curb to provide a watertight connection. Curbs should be a minimum of eight inches above the finished roof and factory insulated to reduce condensation.

Roofi ng may be completed after setting the unit. Roof curbs are in many cases installed on the roof and temporarily covered over for waterproofing purposes much earlier than the construction schedule requires. And in this one sentence lie the benefits and the detriments we face in the roof curb business everyday. Prefabricated roof curbs have been in use since the roof has been utilized for something other than keeping weather out.

The primary function of the curb is to keep weather out while supporting flashing the equipment on it.