Question 1

Guard height on a deck 10 m up in Ontario?

Accepted Answer

At 10 metres up, the 2024 Ontario Building Code requires a guard on any open side where the drop exceeds 600 mm within 1.2 m of the edge. For the deck itself the guard is not less than 1 070 mm high, and Ontario adds a separate rule for exterior stairs and landings more than 10 m above adjacent ground: their guards must be not less than 1 500 mm.

Question 2

Is horizontal cable railing allowed on an Ontario deck?

Accepted Answer

Horizontal cable infill on a required guard can facilitate climbing, which is what Ontario's no-climb rule targets. The 2024 Ontario Building Code, section 9.8.8.6(1) as replaced for Ontario, states that every required guard must be designed so that no member, attachment or opening located between 140 mm and 900 mm above the walking surface will facilitate climbing. Horizontal cables running between those heights are what that rule targets. This is an Ontario-specific rule.

Question 3

What makes a deck guard climbable under Ontario rules?

Accepted Answer

Under Ontario's Building Code, a required guard is considered climbable if any member, attachment or opening located between 140 mm and 900 mm above the walking surface would facilitate climbing. That is the rule in section 9.8.8.6(1) of the 2024 Ontario Building Code, as replaced for Ontario, and it applies to every required guard on a residential deck. The national version of that rule limits the no-climb requirement to guards more than 4.2 metres above the level below.

Question 4

How is guard height measured on Ontario deck stairs?

Accepted Answer

On deck stairs in Ontario, guard height is measured vertically from the top of the guard down to an imaginary line drawn through the nosings of the treads below. That line, not the stringer or the tread surface directly beneath the guard post, is the reference point. The 2024 Ontario Building Code sets the minimum guard height at 900 mm for exterior guards serving not more than one dwelling unit, where the walking surface served is not more than 1 800 mm above finished ground level.

Guards & Railings

Guard height on a deck 10 m up in Ontario?

Is horizontal cable railing allowed on an Ontario deck?

What makes a deck guard climbable under Ontario rules?

How is guard height measured on Ontario deck stairs?