Intent 1:
To limit the probability of an excessive number
or inappropriate location of defects (such as knots, holes, decay,
shake, wane and checks, crimps and the presence of sapwood), which
could lead to a reduction in the watertightness of shingles exposed
to the weather, which could lead to:
- 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.