9.27.5.1.(4)

Intent 1:

To limit the probability of fastening cladding to an inappropriate substrate, which could lead to an inadequate resistance to expected gravity loads and lateral wind loads.

This is to limit the probability of the displacement of cladding, trim and flashing, the opening of joints or the failure of caulking, which could lead to:

• precipitation or meltwater ingress, or
• compromised thermal performance of components intended to provide resistance to heat transfer.

This is to limit the probability of:

• 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,
• deterioration, which could lead to compromised integrity of exterior walls or elements protected by exterior walls, or
• water accumulation in interior spaces.

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.

Intent 2:

To supersede the fastening requirement stated in Sentence (1) and allow wood shingles or shakes to be fastened to wood lath, which has sufficient strength to support the shingles or shakes.