9.27.2.

(1) Except where exterior walls are protected from precipitation or where it can be shown that ingress will not adversely affect occupant health or safety, exterior walls shall be designed and constructed to,

(a) minimize the ingress of precipitation into the assembly, and

(b) prevent ingress into interior space.

(2) Except where exterior walls are protected from specific mechanisms of deterioration, such as mechanical impact and ultraviolet radiation, exterior walls shall be designed and constructed to minimize the likelihood of their required performance being reduced to an unacceptable level as a result of those mechanisms.

(1) Exterior walls exposed to precipitation shall be protected against ingress of precipitation with an exterior cladding assembly consisting of a first plane of protection and a second plane of protection where the wall encloses spaces of residential occupancy or spaces that directly serve spaces of residential occupancy.

(1) Where walls required to provide protection from precipitation comprise assemblies with first and second planes of protection,

(a) the first plane of protection shall,

(i) consist of cladding, with appropriate trim, accessory pieces and fasteners, and

(ii) be designed and constructed to minimize the passage of rain and snow into the wall by minimizing holes and managing precipitation ingress caused by kinetic energy of raindrops, surface tension, capillarity, gravity, and air pressure differences,

(b) the second plane of protection shall be designed and constructed to,

(i) intercept all precipitation that gets past the first plane of protection, and

(ii) effectively dissipate any precipitation to the exterior, and

(c) the protection provided by the first and second planes of protection shall be maintained at,

(i) wall penetrations created by the installation of components and services such as windows, doors, ventilation ducts, piping, wiring and electrical outlets, and

(ii) the interface with other wall assemblies.

(1) A clearance of not less than 200 mm shall be provided between finished ground and cladding that is adversely affected by moisture, such as untreated wood, plywood, OSB, waferboard and hardboard.

(2) A clearance of not less than 50 mm shall be provided between a roof surface and cladding that is adversely affected by moisture, such as untreated wood, plywood, OSB, waferboard and hardboard.