The Ontario Building Code | Accumulation and Disposal
5.6.2.2. Accumulation and Disposal
(1) Where water, snow or ice can accumulate on a building, provision shall be made to minimize the likelihood of hazardous conditions arising from such accumulation.
(2) Where precipitation can accumulate on sloped or horizontal assemblies, provision shall be made for drainage conforming with Section 7.4.
(3) Where downspouts are provided and are not connected to a sewer, provisions shall be made to,
(a) divert the water from the building, and
(b) prevent soilerosion.
(4) Junctions between vertical assemblies, and sloped or horizontal assemblies, shall be designed and constructed to minimize the flow of water from the sloped or horizontal assembly onto the vertical assembly.
In Plain Language
Where water, snow, or ice can accumulate on a building, provisions must be made to minimize the likelihood of hazardous conditions arising from that accumulation, such as ice damming or excessive roof loading.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.