Deck and Porch Guard Requirements
Last updated: June 2026
Minimum guard height, opening limits, and load requirements.
Detailed explanation
Guards are required where the difference in elevation exceeds 600 mm (approximately 24 inches) in Part 9 applications. Guard height is measured from the adjacent walking surface.
On stairs, guard height is measured from the line of nosings and may differ from guard height on flat surfaces. Infill openings must limit the passage of a small sphere.
Guards must resist outward and inward loads specified in the code. Posts, rails, and infill must be connected to withstand these forces.
Ontario Building Code references
Ontario Building Code
Section 9.8.8. — Guards
Height, openings, and loads.
Ontario Building Code
Section 9.8.7. — Handrails
Handrail versus guard distinctions on stairs.
Examples
- A deck 24 inches above grade needs guards on open sides.
- Horizontal cable railings must still meet opening size limits at posts and tension settings.
Common mistakes
- Using 36-inch guard height on a flat deck when 42 inches is required.
- Wide spacing between balusters that fails the sphere rule.
- Not distinguishing guard height on stairs from guard height on landings.
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