Sentence 9.26.4.6.(1)

Intent 1:

To limit the probability of:

• cracking, tearing or shrinking of built-up roof membranes (when returned up walls at a sharp angle),
• interruption of roofing membranes at junctions with walls or chimneys, or
• water temporarily ponding and eventually overtopping cant strips.

This is to limit the probability of precipitation or meltwater ingress into or through roofs, masonry walls or chimneys, which could lead to deterioration, which could lead to the structural failure of roofs or walls, or elements protected by such assemblies, which could lead to harm to persons.