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.
Ask your own code question
Canadian Codes answers questions like this one from national, provincial, territorial, and municipal sources, and cites the document, section, and page so you can check it yourself.
Try it free →Related questions
- When can an exterior guard be lower than 1 070 mm? Canada
- What is the minimum ceiling height for a bedroom? Canada
- What is the minimum ceiling height in an unfinished basement? Canada
- What ceiling height is required in a secondary suite? Canada
- How wide must a hallway be inside a dwelling unit? Canada
- When do two areas count as a combination room? Canada
- At what supported joist span do the basic footing width tables stop applying? Canada
- What is the minimum clear height in a storage garage? Canada
- What maximum air leakage rate is allowed for the air barrier system? Canada
- How often must self-contained emergency lighting be tested? Canada
- What minimum slope is required for a drainage pipe NPS 3 or smaller? Canada
- What is the minimum ceiling height for a bedroom in Ontario? Ontario
- What ceiling height is required in a basement in Ontario? Ontario
- What ceiling height do I need for a basement apartment in Ontario? Ontario
- What clear height is required over stairs in an Alberta secondary suite? Alberta
- When can an exterior guard on a BC house be 900 mm high? British Columbia
- Does the Manitoba Building Code apply to a shed under 10 m²? Manitoba
- Where are carbon monoxide alarms required in Manitoba? Manitoba
- What size egress window does a Manitoba basement need? Manitoba
- What fire separation is required between an attached garage and a Manitoba dwelling? Manitoba