Sentence 9.26.4.8.(5)

  1. OH1
  2. OS2
  3. OS1
  4. OP1
  5. OS3

Objective

OH1 Indoor Conditions

Attribution

Intent

Intent 1:

To exempt situations from the application of Sentence 9.26.4.8.(1) where sufficient protection is provided by flashing and counter flashing.

Intent 2:

To limit the probability that the flow of water down a roof's surface will be interrupted by a wide chimney, which could lead to a temporary increase in water depth beyond the depth protected by roofing or by the vertical leg of flashing at the chimney, which could lead to:

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

This is to limit the probability of:

  • an inadequate control of relative humidity, temperatures of interior spaces or water accumulation,
  • the generation of pollutants from biological growth or from materials that become unstable on wetting, or
  • deterioration, which could lead to compromised integrity of roofs or assemblies protected by roofs.

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.

Top of Page