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.
This is to limit the probability of
compromised structural integrity, which could lead to:
- the structural collapse of wood-frame construction,
or
- where supporting walls serve as an environmental separator
or where roof joists support elements of an environmental separator,
the excessive deformation, displacement or failure of required environmental
separation elements, which could lead to deterioration, which could
lead to further compromised structural integrity of roofs or environmental
separators.
This is to limit the probability of:
- the space being unsuitable for its intended use,
- compromised operation of windows or doors, or
- damage to the building.