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OBC DIVISION B · PART 4 — STRUCTURAL DESIGN

What loads must a guard (railing) resist under the Ontario Building Code?

Part 4 requires guards to resist specified horizontal and concentrated loads — for example, a horizontal load applied at the top of the guard and loads on individual elements — with values set out in Table 4.1.5.14.

Code reference — verbatim
The minimum specified horizontal load applied inward or outward at the minimum required height of every required guard shall be as provided in Table 4.1.5.14. For guards within dwelling units, the Table specifies a horizontal load of 0.5 kN/m or a concentrated load of 1.0 kN applied at any point, whichever governs; exterior balconies and decks serving a single dwelling unit use the same values, while guards in other locations require higher loads such as 0.75 kN/m.
OBC Division B, Article 4.1.5.14. and Table 4.1.5.14.
What this means in practice

Guards must be engineered for three distinct load cases: a distributed horizontal load along the top, a concentrated load at any single point on the top, and loads applied to individual in-fill elements (like pickets) — each checked separately, not together. Public and assembly locations demand higher loads than guards inside a dwelling unit. For houses and small buildings, Part 9 provides prescriptive guard solutions (SB-7 deck guard details) so you do not need engineering — but any non-standard guard design, glass guard, or guard in a Part 3 building must satisfy Part 4 loads, usually with an engineer's involvement.

Plain language

A railing has to be strong enough that a crowd leaning on it, or one person hitting it hard in one spot, will not send it over the edge. Standard house railings can follow the pre-approved details; anything custom needs the numbers checked.

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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.