Intent 1:
To limit the probability of instability of the roof
framing in constructions without ridge support where roofs are sufficiently
steep to effectively shed snow, which could lead to an inability to
resist expected gravity loads, which could lead to the lower ends
of rafters or joists moving outward, which could lead to:
- the failure of roof rafters or joists, or supporting
walls, or
- the excessive deflection of roof rafters or joists.
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.