Intent 1:
To limit the probability of:
- an inadequate bearing area between the staple's crown
and the shingle's surface, which could lead to excessive stress on
the staple/shingle interface, which could lead to pull-through, or
- an inadequate resistance to withdrawal from the substrate.
This is to limit the probability of
the displacement of shingles, which could lead to water penetrating
directly to roof decking or sheathing.
This is to limit the probability of:
- roofing detaching and falling, or
- precipitation or meltwater ingress, which could lead
to deterioration, which could lead to the structural failure of roofs
or walls or of assemblies protected by roofs or walls.
This is to limit the probability of harm to persons.
Intent 2:
To supersede the requirement for 4 fasteners stated
in Sentences 9.26.2.4.(2) and 9.26.7.4.(1), and increase the number of fasteners to 6 for
constructions where relatively narrow staples are used.