Does a Wall in New Brunswick Need a Vapour Barrier?
In New Brunswick, a wall governed by the National Building Code of Canada needs a vapour barrier whenever it’s insulated.
Does a Wall in Nevada Need a Vapor Barrier?
The 2021 International Residential Code answers this directly at R702.7: a vapor retarder is required on the interior side of frame walls, at a class set…
Does a Wall in Nebraska Need a Vapor Barrier?
Yes. Nebraska sits entirely inside IECC climate zone 5A, and the 2021 International Residential Code requires a vapor retarder on the interior side of…
Does a Wall in Montana Need a Vapor Barrier?
Yes. Montana sits entirely in IECC climate zone 6B, and under the 2021 International Residential Code, that zone falls outside the exception that waives…
Does a Wall in Missouri Need a Vapor Barrier?
A wall in Missouri doesn’t have one answer. The state’s 87 counties in climate zone 4A and 26 counties in zone 5A fall under the 2021 IRC’s default rule…
Does a Wall in Mississippi Need a Vapor Barrier?
No. Under the 2021 International Residential Code, a vapor retarder is not required in Climate Zones 1, 2 and 3, and Mississippi’s 82 counties fall…
Does a Wall in Minnesota Need a Vapor Barrier?
In Minnesota, the answer is yes. The 2021 International Residential Code requires a vapor retarder on the interior side of framed walls, and the code’s…
Does a Wall in Michigan Need a Vapor Barrier?
Yes. Under Section R702.7 of the 2021 International Residential Code, above-grade frame walls in Michigan need an interior vapor retarder, and that…
Does a Wall in Massachusetts Need a Vapor Barrier?
Yes. Massachusetts sits entirely within IECC Climate Zone 5A, and under the 2021 International Residential Code, that zone falls outside the exception…
Does a Wall in Maryland Need a Vapor Barrier?
Yes. Every one of Maryland’s 24 counties falls outside the International Residential Code’s warm-zone exception, so a vapor retarder on the interior side…