Intent 1:
To limit the probability of:
- insufficient length, which could lead to an insufficient
overlap of wood shakes at the maximum exposure permitted, which could
lead to an insufficient number of shake plies over the roof surface,
which could lead to coinciding defects,
- insufficient width or shrinkage and cracking of excessively
wide wood shakes, which could lead to an excessive number and proximity
of cracks or joints, which could lead to relatively short paths for
water penetration past shingles, or
- significant differences in the thickness of shakes,
which could lead to the ingress of wind-driven rain or snow through
gaps.
This is to limit the probability of:
- water penetrating directly to roof decking or sheathing,
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.