Intent 1:
To limit the probability that valley flashing, in
combination with the top layer required by Sentence 9.26.4.3.(6), will be unable to resist structural and environmental loads (such
as those imposed by foot traffic, UV exposure, snow accumulation,
ice damming, rain and freeze-thaw cycling), which could lead to the
displacement of roofing.
This is to limit the
probability of:
- 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.