4.1088.8 Installation/Correction of Unconditioned Attic Ventilation

Topic: 
Attics
Subtopic: 
Special Considerations
For supporting material, see Building America Solution Center.
Desired Outcome: 
Properly restored vents minimize moisture and ice dams
TitleSpecification(s)Objective(s)
4.1088.8a
Pre-inspection

Conduct pre-inspection in accordance with SWS 2.0100.4 Work Area Inspection and Stabilization

Ensure safety, effectiveness, and durability of improvements

4.1088.8b
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 thermal boundary Thermal boundary The separation between the interior and exterior environments of a building that slows heat flow

Attic ventilation will be recommended or installed only if:

  • The presence of an effective 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 thermal boundary Thermal boundary The separation between the interior and exterior environments of a building that slows heat flow between the attic and the living space is verified
  • Appropriate attic sealing and proper insulation is specified as part of the work scope
  • Ignition barrier Ignition barrier Any layer of material that protects another from catching fire due to heat or spark and thermal boundaries are provided when foam plastic materials are used

Ensure presence of continuous 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 thermal boundary Thermal boundary The separation between the interior and exterior environments of a building that slows heat flow

4.1088.8c
Vent type

Attic vent types will be consistent with requirements for their specific location (e.g., exterior soffit, gable end, roof) and material and intended use (e.g., metal vent on metal roof)

Ventilation opening area and configuration will comply with applicable building code

Ensure vent meets proper performance characteristics for location and roofing type

4.1088.8d
Vent location

Placement of attic vents will be considered for proper air flow and prevention of entry of wind-driven rain or snow

Encourage proper air flow

Minimize entry of wind-driven rain or snow

4.1088.8e
Ventilation baffling

Baffling for attic soffit vents will be installed to:

  • Ensure proper air flow
  • Prevent wind washing of insulation
  • Allow maximum insulation coverage
  • Ensure baffle terminates above insulation

Minimum clearance between insulation and roof deck will be 1"

Ensure vent allows proper air flow without compromising insulation performance

4.1088.8f
Ventilation screens

All attic ventilation will have screens with noncorroding wire mesh with openings of 1/8" to prevent pest entry (e.g., birds, bats, bees)

Existing vents that are not screened will be covered with noncorroding wire mesh with openings of 1/8"

Prevent pest entry