Climate Zones for Roof Curbs

How much clearance (height in inches) does your roof curb need?  The answer depends on the climate your home or building is in.

Roof curbs are only intended for low slope or flat roofs. For a roof pitch 2/12 Pitchor Lower, refer to the chart under the map below. 

You can use taller roof curbs for additional clearance in warmer climate zones, but you can't use shorter ones in colder zones.

Click here to find the zone of your county.

Source: US Office Of Energy Efficiency & Renewable Energy