9.19.1.2.(2)

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.

Top of Page