Does a Wall in Georgia Need a Vapor Barrier?
No, not as a blanket requirement. Every one of Georgia’s counties falls into either IECC Climate Zone 3A or Climate Zone 2A, and the 2021 International…
Does a Wall in Florida Need a Vapor Barrier?
No. Under the 2021 International Residential Code, Section R702.7, a wall in Florida is not required to carry an interior vapor retarder, because the…
Does a Wall in Delaware Need a Vapor Barrier?
Delaware sits entirely in IECC climate zone 4A, and the 2021 International Residential Code exempts only Climate Zones 1, 2 and 3 from the interior vapor…
Does a Wall in Connecticut Need a Vapor Barrier?
Yes. Connecticut sits entirely within IECC Climate Zone 5A, and under the 2021 International Residential Code, that means a Class-appropriate vapor…
Does a Wall in Colorado Need a Vapor Barrier?
Yes. Every county in Colorado sits in Climate Zone 4B, 5B, 6B, or 7, and none of those fall inside the exception the 2021 International Residential Code…
Does a Wall in California Need a Vapor Barrier?
A wall in California may or may not need an interior vapor retarder, and the answer changes county by county.
Does a Wall in British Columbia Need a Vapour Barrier?
Yes. In British Columbia, as everywhere else the National Building Code applies, a vapour barrier is required in insulated wall assemblies.
Does a Wall in Arkansas Need a Vapor Barrier?
Arkansas doesn’t give one answer to this question. The state’s 75 counties split across two IECC climate zones, and the 2021 International Residential…
Does a Wall in Arizona Need a Vapor Barrier?
No single answer covers the whole state. Arizona’s 15 counties fall across four IECC climate zones, and the 2021 International Residential Code ties the…
Does a Wall in Alberta Need a Vapour Barrier?
Yes. Under Alberta’s building code, a vapour barrier is required in insulated wall assemblies, and unlike the American model code, that requirement…