Intent 1:
To limit the probability of precipitation or meltwater
ingress at horizontal joints between cladding elements.
This is to limit the probability of:
- compromised thermal performance of components intended
to provide resistance to heat transfer, which could lead to 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, or
- deterioration, which could lead to compromised integrity
of exterior walls or elements protected by exterior walls.
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 limit the application of Sentence 9.27.3.8.(1), where the wall assembly is constructed such that:
- precipitation or meltwater ingress at horizontal joints
will be minimized, or
- moisture that bypasses the cladding will be dissipated.