Sentence 9.19.1.2.(2)

  1. OH1
  2. OS2

Objective

OH1 Indoor Conditions

Attribution

[F51-OH1.3]Applies to sloped roof assemblies that may be subject to ice damming.

Intent

Intent 1:

To limit the probability of an inadequate vent area for roofs, which could lead to:

  • condensation,
  • the accumulation of moisture, or
  • the formation of ice dams.

This is to limit the probability of:

  • the ingress of water, or
  • compromised thermal performance of components intended to provide resistance to heat transfer.

This is to limit the probability of:

  • an inadequate control of the temperature of interior spaces or relative humidity,
  • the generation of pollutants from biological growth or from materials that become unstable on wetting,
  • deterioration, which could lead to compromised integrity of ceilings acting as environmental separators, or
  • water accumulation in interior spaces.

This is to limit the probability of:

  • negative effects on the air quality of indoor spaces,
  • the inadequate thermal comfort of persons, and
  • contact with moisture.

This is to limit the probability of harm to persons.

Intent 2:

To supersede the requirement stated in Sentence 9.19.1.2.(1), where the air pressure differential from eave to ridge is limited or where the space below the sheathing is interrupted by framing.

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