9.26.6.1.(2)

Objective

OS2 Structural Safety

Attribution

Intent

Intent 1:

To limit the probability of insufficiently moisture-permeable underlay, which could lead to moisture (from leakage or condensation) collecting on the upper surface of underlay, which could lead to long-term wetting of shingles, which could lead to:

  • condensation, or
  • precipitation or meltwater ingress.

This is to limit the probability of deterioration, which could lead to the structural failure of roofs or assemblies protected by roofs, which could lead to harm to persons.

Top of Page