OBC DIVISION B · PART 5 — ENVIRONMENTAL SEPARATIONUpdated for the 2024 Ontario Building Code

Section 5.7 — Surface and Ground Water (See Note A-5.7.)

Full text of Section 5.7 (Surface and Ground Water (See Note A-5.7.)) — Division B, Part 5 (Environmental Separation) of the 2024 Ontario Building Code, with every article reproduced below.

5.7.1.Site Factors

5.7.1.1.Application permalink →

(1) This Subsection applies to the location of buildings, the grading of building sites, the directing of surface water away from building assemblies and the provision of means for drainage.

5.7.1.2.Required Protection permalink →

(1) The building shall be located, the building site shall be graded, or surface water shall be directed away from building assemblies so as to (a) minimize the accumulation of surface water against the building in a manner that does not adversely affect adjacent buildings or properties, or (b) accommodate the accumulation of surface water on the property in a manner that does not adversely affect the building or adjacent buildings or properties. (2) Drainage shall be provided to direct surface water away from building assemblies separating interior space from the ground, except, (a) where the building assembly is designed in accordance with Subsection 5.7.2. to withstand continuous hydrostatic pressure, or (b) where it can be shown that the lack of drainage will not adversely affect any of (i) the health or safety of building users, (ii) the intended use of the building, or (iii) the operation of building services. (See Note A-5.7.1.2.(2))

5.7.2.Protection Against Hydrostatic Pressure

5.7.2.1.Application permalink →

(1) This Subsection applies to waterproofing materials, components, assemblies and systems applied to building assemblies that separate dissimilar environments and are subjected to hydrostatic pressure.

5.7.2.2.Design of Building Elements under Hydrostatic Loads permalink →

(1) Waterproofing materials, components, assemblies and systems described in Article 5.7.2.1. shall be designed in accordance with Subsection 5.1.4. (2) Hydrostatic design loads shall be determined in accordance with Subsection 5.2.2.

5.7.2.3.Required Protection permalink →

(1) Waterproofing materials, components, assemblies and systems described in Article 5.7.2.1. shall comply with Article 5.7.3.2.

5.7.3.Protection Against Ground Water

5.7.3.1.Application permalink →

(1) This Subsection applies to the protection of building assemblies that separate interior space from the ground.

5.7.3.2.Required Protection permalink →

(1) Except as provided in Sentence (2) and Article 5.7.3.4., building assemblies described in Article 5.7.3.1. shall be protected by waterproofing in accordance with Article 5.7.3.3. so as to minimize the ingress of water into the building or the accumulation of water against the building. (2) Waterproofing is not required where it can be shown that (a) a building is designed to accommodate the ingress or accumulation of ground water, or (b) the ingress or accumulation of ground water will not negatively affect (i) the health or safety of building users, (ii) the intended use of the building, or (iii) the operation of building services.

5.7.3.3.Waterproofing permalink →

(1) Waterproofing materials, components, assemblies, or systems installed to provide the required protection shall form a continuous and impervious barrier to the ingress of ground water and be capable of accommodating, (a) imperfections, construction joints, control joints and expansion joints, (See Note A-5.7.3.3.(1)(a)) (b) junctions between different building assemblies, and (c) elements penetrating building assemblies.

5.7.3.4.Where Dampproofing is Permitted permalink →

(1) Vertical building assemblies that separate interior space from the ground are permitted to be dampproofed where, (a) such assemblies are not subjected to hydrostatic pressure, (b) the substrate is cast-in-place concrete, and (c) a drainage layer is installed between the building assembly and the soil. (See Note A-5.7.3.4.(1)) (2) Joints, junctions and penetrations shall be designed and constructed to maintain the continuity of the dampproofing.

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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.