Break in continuity between drained and vented air spaces or drainage material installed to provide a capillary break between the cladding and backing assembly, in cladding assemblies to which Subsection 9.27.2. applies [see Article 9.27.1.1. for application of Subsection 9.27.2.], and concealed spaces in constructions that project over the top of such air spaces or drainage materials.

To limit the probability that moisture will transfer from drained and vented air space or drainage material in the wall into assemblies above the wall, which could lead to the accumulation of moisture.

This is to limit the probability of:

• compromised thermal performance of components intended to provide resistance to heat transfer, which could lead to an inadequate control of the temperature of interior spaces or relative humidity,
• the generation of pollutants from biological growth or from materials that become unstable on wetting, or
• deterioration, which could lead to compromised integrity of roofs and ceilings acting as 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.