The Ontario Building Code | First and Second Planes of Protection First and Second Planes of Protection

(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.