How To Set A Roof Curb

Pressure treated nailers should be provided by the curb manufacturer to receive roofing felts and eliminate noise transfer.

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. The rooftop unit may be mounted immediately after the curb is installed. Prefabricated roof curbs have been in use since the roof has been utilized for something other than keeping weather out. 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.

After leveling the curb we anchored the curb down with 4 screws to the metal sub roof. And in this one sentence lie the benefits and the detriments we face in the roof curb business everyday. Curb installation should be a part of the roof deck not on top of insulation or roofing materials. Roof curbs are in many cases installed on the roof and temporarily covered over for waterproofing purposes much earlier than the construction schedule requires.

The opening through the metal roof was for the intake duct to the a c unit. After the opening was made for the duct work we then placed the curb in position. Curbs should be a minimum of eight inches above the finished roof and factory insulated to reduce condensation. 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.

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