Roof Curbs - 6 inch Tall

Roof Curb
Prefabricated Roof Curb
Prefabricated Roof Curb

AVP manufactures Roof Curbs that fit Roof Vents and Exhaust Fans with a Curb Mount Flange

A roof curb is a box that acts as an extension from the roof deck. This extension provides a mounting platform for a roof vent or exhaust fan. These roof curbs are intended for flat roofs only.

AVP’s Roof Curbs are manufactured from aluminum and are offered in 3 height options. For climates with minimal snow or no snow at all, a 6 inch tall roof curb is sufficient.

An important reason for the use of a curb is a roofing manufacturer's warranty. Many EPDM, PVC & TPO roofing manufacturers require roofing penetrations to be secured by a curb and a boot. Check with your roofing materials supplier to purchase a boot that slides over the aluminum curb.

The boot provides a factory-approved attachment to the roof deck’s membrane. The upper end of the boot folds into the curb. Then the curb mount flange goes over both the boot and curb. This will provide a perfect seal from the top.

Outer Width

Inside Opening

6"5"6"For a 3" Diameter Vent or FanRC-3-H6
7"6"6"For a 4" Diameter Vent or FanRC-4-H6
8"7"6"For a 5" Diameter Vent or FanRC-5-H6
9"8"6"For a 6" Diameter Vent or FanRC-6-H6
10"9"6"For a 7" Diameter Vent or FanRC-7-H6
11"10"6"For a 8" Diameter Vent or FanRC-8-H6
12"11"6"For a 9" Diameter Vent or FanRC-9-H6
13"12"6"For a 10" Diameter Vent or FanRC-10-H6

Outer Width

Inside Opening

15"13"6"For a 12" Diameter Vent or FanRC-12-H6
17"15"6"For a 14" Diameter Vent or FanRC-14-H6
19"17"6"For a 16" Diameter Vent or FanRC-16-H6
21"19"6"For a 18" Diameter Vent or FanRC-18-H6
23"21"6"For a 20" Diameter Vent or FanRC-20-H6
27"25"6"For a 24" Diameter Vent or FanRC-24-H6


An additional benefit to using a 6 inch tall roof curb is it can act as a hatch or access entry port. The roof vent or exhaust fan can be easily removed. As a result, allowing for quick access to ductwork, electrical lines, or maintenance in the attic below.

Traditionally, roofers build wooden boxes on the roof at the time of the membrane installation. Using prefabricated aluminum curbs reduces the time and need to build the wooden boxes. This will also lower the risk of injury during installation by lowing the time spent on the roof. In addition, any chances to damage the roof in the building process are also lower.

Another safety feature is that aluminum curbs are not flammable. The majority of curbs vent out heat from range hoods or HVAC units. This can cause wooden ones to burn. However, aluminum will not burn, rust, or corrode. Aluminum is safer and easy to clean.

AVP also supplies curbs as an independent part. With a wide range of widths from 6” up to 51”, these curbs can support many roof vents or fans.

Shop roof curbs on AVP’s website:

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