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Vent Clearance Based on Climate

How much clearance (height) does your roof top air intake vent need?

It 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.

It is important to note that for asphalt shingle roofs, and or metal roofs, in climates zones 4 and higher, one should install snow guards / rain diverters above the air intake vents on the roof. 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 that all applications listed below are for when air intake vents are installed on the lower portion of the top side of the roof only and not 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 a 4″ tall collar for zones 1, 2, 3 as long as you also install a rain diverter above the roof vent.

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 a 6″ tall collar for zone 4. A snow guard is highly recommended. 

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 an 8″ tall collar for zones 5, 6. A snow guard is required for this application.

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 an 11″ or 12″ tall collar for zones 7, 8. A snow guard is required for this application.

You can always use taller collars for additional clearance in warmer zones, but you can’t use shorter collars in colder zones.

You can have your vents extra tall, custom collar heights are available.