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Roof ventilation for attached garage

B

bnymbill

Member
Joined
Jan 30, 2013
Messages
33
Location
Baltimore
In reading R806.1, Ventilation required, it says enclosed attic and rafter spaces are required to be ventilated. It makes no distinction between roofs/attics above habitable space or the space above an attached garage.

I'm looking at a house built in 2020, under the 2015 IRC, in climate zone 4. It has a 2.5/12 pitch with rafters 24" OC, R-30 batts, and finished drywall.

The garage roof eave has soffit vents with a net clear area of 103 sq inches. However, there is no exhaust ventilation on the roof.

This seems like a recipe for a moisture trap in the roof assembly. Am I interpreting R806.1 correctly in that it would apply to the roof of of an attached garage with enclosed rafter space?
 
bnymbill said:
In reading R806.1, Ventilation required, it says enclosed attic and rafter spaces are required to be ventilated. It makes no distinction between roofs/attics above habitable space or the space above an attached garage.

I'm looking at a house built in 2020, under the 2015 IRC, in climate zone 4. It has a 2.5/12 pitch with rafters 24" OC, R-30 batts, and finished drywall.

The garage roof eave has soffit vents with a net clear area of 103 sq inches. However, there is no exhaust ventilation on the roof.

This seems like a recipe for a moisture trap in the roof assembly. Am I interpreting R806.1 correctly in that it would apply to the roof of of an attached garage with enclosed rafter space?
Click to expand...
Yes....Someone missed the ridge vent?
 
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