2.0401.1 Air Sealing Moisture Precautions

Topic: 
Moisture
Subtopic: 
Air Sealing
Desired Outcome: 
Ensure durability of repairs and reduce potential for occupant exposure to mold and other moisture-related hazards
For supporting material, see Calculation of the Infiltration Credit, Referenced Standards and Building America Solution Center.
TitleSpecification(s)Objective(s)
2.0401.1a
Moisture precautions for attics

Roof leaks will be repaired before performing attic air sealing or insulation

Moisture sources in the house that can generate moisture into the attic will be identified and removed or reduced

Where possible, water resistant sealants and/or closed cell foams will be used in cold climates.

Plastic, foil, or any other Class 1 vapor barrier Vapor barrier A material that retards the passage of water vapor and contains a perm rating of less than 1  will not be used in hot humid climates

In marine climates, vapor permeable materials will be used to block and seal penetrations in attic
 

Ensure durability of repairs

Reduce potential for occupant exposure to mold and other moisture-related hazards

Prevent moisture from communicating from within the conditioned space into unconditioned attic space.

Increase durability of seal

Avoid moisture-related damage to the home
 
2.0401.1b
Moisture precautions for crawl spaces

Exposed earth will be covered with a continuous, durable, sealed Class 1 vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 a minimum of 6 mils in thickness 

Any vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 shall not encapsulate wood building materials or spray foam

Holes between the crawl space and the living space will be sealed 

Ensure durability of repairs

Reduce potential for occupant exposure to mold and other moisture-related hazards
2.0401.1c
Moisture precautions for the living space

Moisture sources in the home will be identified and removed or reduced

Local ventilation will be installed where appropriate (e.g., baths, kitchens) and vented to outside according to ASHRAE ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers, www.ashrae.org 62.2

Unvented combustion appliances that are not listed to ANSI ANSI American National Standards Institute, www.ansi.org Z21.11.2 will be removed

Ensure durability of repairs

Reduce potential for occupant exposure to mold and other moisture-related hazards
2.0401.1d
Moisture precautions for exterior water

Before air sealing basement or crawl space walls near wet areas, surface water pooling near the foundation will be addressed by:

  • Repairing, modifying or replacing gutters and downspouts
  • Grading and subsurface drainage at critical locations (e.g., localized drain and grading beneath valleys) in accordance with Environmental Protection Agency ( EPA EPA U.S. Environmental Protection Agency, www.epa.gov ) Indoor airPLUS Construction Specifications Section 1.1
  • Possible mitigation by waterproofing or installing draining plane with construction adhesive

Reduce potential for occupant exposure to mold and other moisture-related hazards
TitleSpecification(s)Objective(s)
2.0401.1a
Moisture precautions for attics

Roof leaks will be repaired before performing attic air sealing or insulation

Moisture sources in the house that can generate moisture into the attic will be identified and removed or reduced

Where possible, water resistant sealants and/or closed cell foams will be used in cold climates.

Plastic, foil, or any other Class 1 vapor barrier Vapor barrier A material that retards the passage of water vapor and contains a perm rating of less than 1  will not be used in hot humid climates

In marine climates, vapor permeable materials will be used to block and seal penetrations in attic
 

Ensure durability of repairs

Reduce potential for occupant exposure to mold and other moisture-related hazards

Prevent moisture from communicating from within the conditioned space into unconditioned attic space.

Increase durability of seal

Avoid moisture-related damage to the home
 
2.0401.1b
Moisture precautions for crawl spaces

Exposed earth will be covered with a continuous, durable, sealed Class 1 vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 a minimum of 6 mils in thickness 

Any vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 shall not encapsulate wood building materials or spray foam

Holes between the crawl space and the living space will be sealed 

Ensure durability of repairs

Reduce potential for occupant exposure to mold and other moisture-related hazards
2.0401.1c
Moisture precautions for the living space

Moisture sources in the home will be identified and removed or reduced

Local ventilation will be installed where appropriate (e.g., baths, kitchens) and vented to outside according to ASHRAE ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers, www.ashrae.org 62.2

Unvented combustion appliances that are not listed to ANSI ANSI American National Standards Institute, www.ansi.org Z21.11.2 will be removed

Ensure durability of repairs

Reduce potential for occupant exposure to mold and other moisture-related hazards
2.0401.1d
Moisture precautions for exterior water

Before air sealing basement or crawl space walls near wet areas, surface water pooling near the foundation will be addressed by:

  • Repairing, modifying or replacing gutters and downspouts
  • Grading and subsurface drainage at critical locations (e.g., localized drain and grading beneath valleys) in accordance with Environmental Protection Agency ( EPA EPA U.S. Environmental Protection Agency, www.epa.gov ) Indoor airPLUS Construction Specifications Section 1.1
  • Possible mitigation by waterproofing or installing draining plane with construction adhesive

Reduce potential for occupant exposure to mold and other moisture-related hazards
TitleSpecification(s)Objective(s)
2.0401.1a
Moisture precautions: attics/roofs

Roof leaks will be repaired before performing attic air sealing or insulation

Moisture sources in the house that can generate moisture into the attic will be identified and removed or reduced

Conduct coincident humidity control in the living space (e.g. bath and kitchen fans and dryer exhaust safety outside, crawl space/ basement humidity control addressed)

 

 

Ensure durability of repairs

Reduce potential for occupant exposure to mold and other moisture-related hazards

Prevent moisture from communicating from within the conditioned space into unconditioned attic space.

Increase durability of seal

Avoid moisture-related damage to the home
 
2.0401.1b
Moisture precautions for crawl spaces

Exposed earth will be covered with a continuous, durable, sealed Class 1 vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 a minimum of 6 mils in thickness 

Any vapor retarder Vapor retarder A material that slows the passage of water vapor and contains a perm rating above 1 shall not encapsulate wood building materials or spray foam

Holes between the crawl space and the living space will be sealed 

Ensure durability of repairs

Reduce potential for occupant exposure to mold and other moisture-related hazards
2.0401.1c
Moisture precautions for the living space

Moisture sources in the home will be identified and removed or reduced

Local ventilation will be installed where appropriate (e.g., baths, kitchens) and vented to outside according to ASHRAE ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers, www.ashrae.org 62.2

Unvented combustion appliances that are not listed to ANSI ANSI American National Standards Institute, www.ansi.org Z21.11.2 will be removed

Ensure durability of repairs

Reduce potential for occupant exposure to mold and other moisture-related hazards
2.0401.1d
Moisture precautions for exterior water

Before air sealing basement or crawl space walls near wet areas, surface water pooling near the foundation will be addressed by:

  • Repairing, modifying, or replacing gutters and downspouts
  • Grading and subsurface drainage at critical locations (e.g., localized drain and grading beneath valleys) in accordance with EPA EPA U.S. Environmental Protection Agency, www.epa.gov ) Indoor airPLUS Construction Specifications Section 1.1
  • Possible mitigation by waterproofing or installing draining plane with construction adhesive

Reduce potential for occupant exposure to mold and other moisture-related hazards