PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code

9.27.2.3.First and Second Planes of Protection

(1) Where walls required to provide protection from precipitation comprise cladding 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, (See Subsection 9.27.4.) (b) the second plane of protection shall be designed and constructed to (See Subsection 9.27.3.) (i) intercept all rain and snow that gets past the first plane of protection, and (ii) effectively dissipate any rain or snow to the exterior, and (c) the protection provided by the first and second planes of protection shall be maintained (i) at wall penetrations created by the installation of components and services such as windows, doors, ventilation ducts, piping, wiring and electrical outlets, and (ii) at the interface with other wall assemblies.

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Code text is reproduced for reference from the Ontario Building Code (O. Reg. 163/24, 2024 Building Code Compendium). This page is provided for general information and is not an official copy. Always verify requirements against the official Ontario Building Code and confirm with your local building department.