HELP - Our Exhaust Fan Doesn’t Fit On Our Roof Curb

Rooftop exhaust fans are a crucial part of the exhaust hood system, and is responsible for the removal of smoke, odors, grease, and other air particles from the kitchen space to allow for increased air quality. If you are running a rooftop exhaust fan set up then there are two main components - you have the exhaust fan itself, and you have the roof curb that the fan is mounted to. The rooftop curb is found on the exterior hole where the exhaust fan is installed and protects the opening as well as mounts the exhaust fan 40”+ above the rooftop to meet fire code.


Generally when you buy a rooftop exhaust fan set up you purchase the curb that will fit the fan, however over time you may find yourself in need of a replacement fan. Best case scenario is you are able to find the exact model exhaust fan that is already installed, however with an average life span of 10-15 years it is very possible the make or model exhaust fan is not in production anymore. In these cases you may need to purchase a new model exhaust fan, and you may be unable to find one that will fit your exact curb size. Another scenario is you are upgrade the kitchen space and need more power, and to do that you need to upgrade the size of your exhaust fan and the new exhaust fan does not match up with the existing curb.


In these scenarios you have two general options - option 1 is to replace the curb when you are replacing the exhaust fan. This approach is more time consuming, as well as the more expensive approach. When replacing or upgrading the unit you are generally in time crunch as it is since the kitchen may still be an open and running kitchen. Option 2 - exhaust fan curb adapters. A curb adapter is a pretty simple solution. A common roof curb adapter is machined so that the bottom opening is sized to fit over the existing roof curb, and the top opening is machined to fit the new exhaust fan. This allows the owner to re-use the existing curb regardless of whether the new exhaust fan is too big or too small.


The most sensible option most of the time is an exhaust hood curb adapter. To replace an existing curb requires removal of the existing curb, re-roofing the area to fit the new curb, and then installing the new curb. This requires not only money but time that will require your kitchen to be shut down. An exhaust hood curb adapter is more cost-effective and less time consuming, allowing your kitchen to require little downtime without killing your bank account. HoodMart provides our customers with a wide range of exhaust hood systems - from Compensating (Short Cycle) to Perforated Supply Plenum PSP - as well as all exhaust hood accessories such as no weld Grease Duct, hood filters, canopy hood lights, and curbs. If you still have questions regarding the purchase of your hood system, please feel free to contact one of our experts today by calling us at 1.800.715.1014 or by contacting us through our live chat system.