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 IRC IRC International Residential Code

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