How To Set A Roof Curb

Roofi ng may be completed after setting the unit.

How to set a roof curb.

The opening through the metal roof was for the intake duct to the a c unit. 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. Curbs should be a minimum of eight inches above the finished roof and factory insulated to reduce condensation.

And in this one sentence lie the benefits and the detriments we face in the roof curb business everyday. Pressure treated nailers should be provided by the curb manufacturer to receive roofing felts and eliminate noise transfer. 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. Because the roof is slightly slanted one side of the curb had to leveled with boards.

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. Roof curbs are in many cases installed on the roof and temporarily covered over for waterproofing purposes much earlier than the construction schedule requires. After the opening was made for the duct work we then placed the curb in position. Specify prefabricated roof curbs and related products by a roof curb manufacturer not with or by the equipment manufacturer.

Curb installation should be a part of the roof deck not on top of insulation or roofing materials.