Intent 1:
To limit the probability of excessively long spans,
which could lead to roofs being unable to support additional loads
imposed by heavier roofing materials, which could lead to excessive
movement, deformation or damage to roofing.
Where
wood-frame construction supports or is part of an environmental separator,
this is to limit the probability of the displacement or failure of
required environmental separation elements, which could lead to:
- condensation,
- precipitation ingress,
- excessive heat transfer,
- pollutant ingress, or
- compromised thermal performance of components intended
to resist heat transfer.
This is to limit the probability of:
- inadequate control of temperatures of interior spaces,
drafts, relative humidity or water accumulation,
- the generation of pollutants from biological growth
or from materials that become unstable on wetting, or
- deterioration, which could lead to further compromised
integrity of environmental separators.
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.