2.0403.3 Closed Crawl Spaces—Vapor Retarders on Walls

Topic: 
Moisture
Subtopic: 
Vapor Barriers
Desired Outcome: 
Durable, effective vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 minimizes leakage from ground and air
For supporting material, see Referenced Standards.
TitleSpecification(s)Objective(s)
2.0403.3a
Air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary and vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1

An air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary and vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 will be installed on the interior side of the exterior wall in accordance with 2012 IRC IRC International Residential Code R408. 3

Prevent air and moisture penetration

2.0403.3b
Coverage

An air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary and vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 will be installed a minimum of 1' or as high as possible above outside grade

Prevent air and moisture penetration

2.0403.3c
Termite inspection gap

Where termite pressure exists or local code requires, a 3" inspection gap will be maintained from the top of the insulation to the bottom of any wood

Allow for termite detection

2.0403.3d
Attachment

Vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 will be attached with a durable connection

Vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 will be sealed at punctures and all 12" overlapped seams to prevent air entry

Ensure vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 maintains a fixed position on the exterior wall

Ensure vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 is air tight

2.0403.3e
Piers and interior walls

Vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 will be installed a minimum of 6" above interior grade

Vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 will be attached with a durable connection

Vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 will be sealed at punctures and all 12" overlapped seams to prevent air entry

Prevent ground moisture penetration