How much clearance (height) does your roof air intake vent need?
The answer depends on
1) The climate zone you live in
2) The type of roof you have (how pitched or how flat)
3) The placement of the roof vent on the roof.
Asphalt shingle roofs in climates zones 4 and higher, should install snow guards / rain diverters. This will protect the roof vents from sliding ice and rushing water.
This warning does not apply to low slope / flat membrane roofs 2/12 and under.
Please note, all applications are for when intake vents are installed on the lower portion of the roof. This is not for installing under the overhang of the roof, where you would place soffit vents.
When intake roof vents are installed on the lower portion of a roof and the roof pitch is 3/12 or higher you will need:
You can always use taller collars for additional clearance in warmer zones, but you can’t use shorter collars in colder zones. Additionally, you can have your vents extra tall, custom collar heights are available.