Intent 1:
To limit the probability of:
- insufficient width, which could lead to water flowing
down valleys, spreading horizontally beyond the edges of the flashing
and penetrating the roof assembly, or
- inadequate flexibility, strength or durability, which
could lead to damage under snow and impact loads or exposure to the
elements.
This is to limit the probability of
precipitation or meltwater ingress, which could lead to deterioration,
which could lead to the structural failure of roofs or assemblies
protected by roofs, which could lead to harm to persons.