Intent 1:
To limit the probability of cutouts that coincide
with those of the top layer of shingles, which could lead to less
than the required 2 thicknesses of shingle over the entire roof, which
could lead to insufficient protection of roof decking or sheathing
from moisture absorption, ultraviolet radiation, and freeze-thaw cycling,
which could lead to premature failure, 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 walls or of assemblies protected by roofs or walls.
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.