9.27.3.5.(1)

Intent 1:

To limit the probability of installation or in-service damage to a single unsupported layer of sheathing membrane, which could lead to:

• precipitation ingress, or
• excessive air infiltration or “wind-washing,” which could lead to condensation or excessive heat transfer.

This is to limit the probability of deterioration, which could lead to compromised structural integrity of exterior walls, which could lead to harm to persons.