How high must a guard be on a deck in Ontario?
A guard must be at least 1 070 mm high, dropping to 900 mm where the walking surface it serves is not more than 1 800 mm above the finished ground.
Conditions and exceptions
- A guard is required where the walking surface is more than 600 mm above the adjacent level.
- The 900 mm allowance is for exterior guards serving a single dwelling unit.
- Openings must not permit a 100 mm sphere to pass through.
- Toronto and other municipalities administer the Ontario Building Code but may add permit conditions.
Where this comes from
Ontario Building Code
This page states the requirement and points you to the publisher. It does not reproduce the code text — read the provision itself at the official source below.
Read the official text at Ontario — King's Printer →Verify this against the code edition actually adopted where you are building. Provinces, territories, and municipalities amend on their own schedules, and where the governing document and this page disagree, the governing document controls. This is not legal, engineering, or permitting advice. Last reviewed 2026-08-12.
Why the requirement is written this way
This page gives the figure. These notes explain the reasoning behind it and what it means on site.
Guards on Balconies and High Drops
Field NotesWhy Stair Guards Fail When Deck Guards Pass
Field NotesWhy Handrails Fail Inspection
Ask your own code question
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