Moisture protection at joints of non-wood-based rigid exterior insulating sheathing and exterior insulating sheathing with an integral sheathing membrane, where one of these is installed in lieu of a sheathing membrane, in cladding assemblies to which Subsection 9.27.3. applies [see Article 9.27.1.1. for application of Subsection 9.27.3.].

To limit the probability of inadequate sealing to prevent moisture ingress or of inappropriate detailing at joints, 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 the failure of required environmental separation elements, which could lead to:

• compromised thermal performance of components intended to resist heat transfer, which could lead to an inadequate control of the temperature of interior spaces, drafts, relative humidity or water accumulation,
• the generation of pollutants from biological growth or from materials that become unstable on wetting, or
• deterioration, which could lead to further compromised integrity of environmental separators.

This is to limit the probability of:

• negative effects on the air quality of indoor spaces,
• the inadequate thermal comfort of persons, and
• contact with moisture.

This is to limit the probability of harm to persons.