Roof top mounted HVAC units (RTU’s) are mounted on top of roof curbs that provide the following main functions:

  1. Attach the RTU to the building structure with considerations for wind and seismic loads.
  2. Direct the air flow from the supply outlet of the RTU into the supply ducting of the building.
  3. Direct the return air from the building back into RTU.
  4. Seal the openings in the roof as an integral part of the roofing system.
  5. Some roof curbs also provide a function of vibration isolation to reduce noise generation and transmission into the building. See our vibration isolation curbs.

Many of our competitors make their curbs out of light gauge steel.  This is because their locations do not need to meet the stringent wind load requirements of the Florida Building Code.  Plenums provides all our curbs with 16-gauge minimum G90 Galvanized Steel so that all our curbs can be rated up to 170 mph and up to 60 ft mounting height to FBC 2020 standards.  If your HVAC application has more stringent requirements than this, please let us know in advance and we can meet your wind rated roof curb requirements. While some of our curb models are NOA rated by Miami Date Product Control, it is not feasible to get an NOA on all our range of 1000’s of curb variations. However, we can provide job specific wind load certifications signed off by a Florida Licensed Professional Engineer for your HVAC project.

Plenums can provide knockdown or welded roof curbs.  In some instances, we can provide very large curbs with welded subassemblies or as a combination of welded and knockdown sections.

Roof Curb Features

  • Heavy gauge galvanized steel construction.
  • 1" x 4" wood nailer.
  • 1/4" x 1-1/4" gasketing.
  • Knockdown or Welded construction available.
  • Custom options available.
  • Wind rated roof curbs

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