Under the 2024 Ontario Building Code, a guard is required wherever a walking surface has a drop of more than 600 mm within 1.2 m, and most guards must be at least 1,070 mm (about 42 in) high, or 900 mm inside a dwelling unit and on low exterior surfaces serving a single house. Required stair handrails must be 865 mm to 1,070 mm high. Guard openings must stop a 100 mm sphere, and the zone between 140 mm and 900 mm above the floor must not give children a foothold. The details below come from Section 9.8. of the 2024 Ontario Building Code (Part 9, houses and small buildings).
Guards and handrails are different things
The Ontario Building Code treats these as two separate components with separate rules:
- A guard is a protective barrier along an open edge (stairs, landings, balconies, porches, mezzanines) that keeps people from falling off.
- A handrail is the rail you grip for support and balance when using stairs or ramps.
A steel railing on an open stair often does both: the top of the guard runs at guard height, and a separate handrail is mounted at handrail height, or the guard's top rail is shaped and positioned to serve as the handrail where the heights allow. Either way, each function has to meet its own requirements.
These rules apply to Part 9 buildings: those of three storeys or less with a building area up to 600 m² in the residential, business, mercantile and medium- and low-hazard industrial groups. Larger buildings fall under Part 3, which has its own stair, guard and handrail provisions. Your designer will confirm which part applies.
When a guard is required
A guard is required on each side of a walking surface that isn't protected by a wall wherever the difference in elevation between the walking surface and the adjacent surface within 1.2 m is more than 600 mm. That includes flights of steps, ramps, exterior landings, porches, balconies, mezzanines, galleries and raised walkways. The leading edge at the top of a flight doesn't need a guard. Guards aren't required at loading docks, at floor pits in repair garages, or where access is only for maintenance.
Measure the drop to the lowest surface within 1.2 m of the edge, not straight down. A deck that looks low at the house can be well over 600 mm at the outer edge if the yard slopes away.
Guard heights in Ontario
| Location | Minimum guard height |
|---|---|
| General rule (all guards not listed below) | 1,070 mm (about 42 in, or 3 ft 6 in) |
| Within a dwelling unit or a house with a secondary suite, including common spaces | 900 mm (about 35-1/2 in) |
| Exterior guards serving one dwelling unit or a house with a secondary suite, where the walking surface is no more than 1,800 mm above finished ground | 900 mm (about 35-1/2 in) |
| Exterior stairs and landings more than 10 m above adjacent ground | 1,500 mm (about 59 in) |
On stairs, guard height is measured vertically from the top of the guard to a line drawn through the tread nosings. On landings, balconies and floors, it is measured from the walking surface. Heights are minimums, so a taller guard is fine as long as the other rules are met.
Openings and climbability
Openings through the guard
Openings through a required guard must be sized to stop a 100 mm sphere from passing through. For a steel picket railing, that means the clear gap between pickets, and between the bottom rail and the floor or landing, has to be less than 100 mm. On stairs, the triangular opening formed by the riser, the tread and the bottom rail of the guard must stop a 150 mm sphere (this triangle rule doesn't apply in industrial occupancies).
The code also checks that pickets can't be pushed apart. With a 0.1 kN load applied to adjacent vertical elements in opposite directions, the opening still has to meet the sphere limit. Thin flat bar or widely spaced posts can fail this even if the unloaded gap looks fine.
Guards in industrial occupancies (other than storage garages) are permitted to use a top rail with intermediate horizontal rails that stop a 535 mm sphere.
Designed not to be climbed
Required guards (except in industrial occupancies, and where it can be shown the openings don't create a hazard) must be designed so that no member, attachment or opening between 140 mm and 900 mm above the walking surface makes it easier to climb. In practice this rules out horizontal rails, cables or decorative elements in that zone that a child could use as a ladder. Vertical pickets are the straightforward way to comply in steel.
Handrail rules
Height and number of handrails
Required handrails must be 865 mm to 1,070 mm high (about 34 to 42 in), measured vertically from the top of the handrail to a line tangent to the tread nosings, or to the surface of the ramp, floor or landing. Extra handrails beyond those required don't have to meet the height range.
| Location | Stairs under 1,100 mm wide, straight | Stairs under 1,100 mm wide, curved | Stairs 1,100 mm wide or more |
|---|---|---|---|
| Within a dwelling unit or house with a secondary suite | 1 side | 1 side | 1 side |
| All other locations | 1 side | 2 sides | 2 sides |
Within a single dwelling unit, handrails aren't required on interior stairs with no more than 2 risers, exterior stairs with no more than 3 risers, or ramps rising no more than 400 mm. Exterior stairs with more than 3 risers serving one dwelling unit need only one handrail.
Graspability, clearance and extensions
- Graspable. Handrails must be continually graspable along their whole length, with nothing on or above them that breaks a handhold. Round tube or pipe, or another profile you can wrap your fingers around, is the usual choice. A wide flat bar may not let your fingers curl under it, so check the profile with your designer.
- Clearance. At least 50 mm between the handrail and the wall behind it, or 60 mm if the surface behind is rough or abrasive.
- Continuity. Required handrails must be continuously graspable from the bottom riser to the top riser. In a single dwelling unit, a handrail may start from a newel post or volute on the bottom tread.
- Extensions. Outside a single dwelling unit, at least one handrail must extend horizontally at least 300 mm beyond the top and bottom of each flight.
- Projection. Handrails and anything below them, including brackets and stringers, may not project more than 100 mm into the required stair width.
- Ends. Handrails must end in a way that doesn't obstruct people or create a hazard. A return to the wall or a post is the usual steel detail.
Loads: what a steel railing has to resist
Guards and handrails have to be strong as well as the right shape. Handrails and their supports must resist a concentrated load of at least 0.9 kN applied at any point and in any direction, plus a uniform load of 0.7 kN/m for handrails other than those serving a single dwelling unit. Guards must resist the loads in Table 9.8.8.2., which include a horizontal load at the top of the guard (0.5 kN/m or a 1.0 kN point load within dwelling units and for exterior guards serving up to two dwelling units, and 0.75 kN/m or 1.0 kN for most other guards), loads on the infill and a vertical load on the top.
For a steel railing, the infill is rarely the weak point. The posts, the welds at the base, and the anchors into concrete, wood framing or steel are. A post welded to a small base plate with light anchors near the edge of a concrete slab can look solid and still fail the load. Ontario also publishes Supplementary Standard SB-7, "Guards for Housing and Small Buildings", but its deemed-to-comply details cover wood guards only. A steel guard has to be shown to meet the load requirement by design, so ask whether your railing needs an engineer's stamp.
Glass and other infills
Glass used in guards must be safety glass (laminated or tempered, to CAN/CGSB-12.1) or wired glass to CAN/CGSB-12.11-M. Steel frames with glass panels still have to meet the height, load and opening rules.
Steel railing details that make inspections easier
- Shop drawings showing heights, picket spacing, post spacing and anchorage, checked against the code before fabrication.
- Welded connections done by certified welders. Our article on why hire a CWB-certified fabricator explains what that certification covers.
- Corrosion protection for exterior railings, such as galvanizing with paint over it, since rust at the base of a post weakens the part that carries the load.
- Measured from the finished surface. Heights and gaps are checked at the finished floor, tread or decking, so allow for flooring that isn't installed yet.
If the railing goes on a new steel stair, the stair dimensions have their own rules, covered in Ontario Building Code rules for steel stairs. For budgeting, see what drives steel railing cost per foot.
Custom steel railings from Procut
We fabricate custom steel railings, guards and stairs in our shop in Erin, with CWB certified welding and shop drawings prepared in-house, and deliver across the GTA and Ontario. Send your drawings, sketches or site measurements and we will prepare a quote. Engineering services are available for projects that need them.
Request a railing quote, or see our services for miscellaneous steel fabrication, shop drawings and delivery.
Frequently asked questions
How high does a steel railing need to be in Ontario?
Under the 2024 Ontario Building Code, guards must generally be at least 1,070 mm (about 3 ft 6 in) high. Guards inside a dwelling unit can be 900 mm, and exterior guards serving one dwelling unit can be 900 mm where the walking surface is no more than 1,800 mm above finished ground.
What height should a stair handrail be in Ontario?
Required handrails on stairs and ramps must be 865 mm to 1,070 mm high (about 34 to 42 in), measured from a line drawn through the tread nosings, or from the ramp, floor or landing surface.
When is a guard required in Ontario?
A guard is required on each side of a walking surface not protected by a wall where there is a drop of more than 600 mm to the adjacent surface within 1.2 m, including stairs, landings, porches, balconies and mezzanines.
How far apart can railing pickets be?
Openings through a required guard must stop a 100 mm sphere from passing through, so the clear gap between steel pickets has to be less than 100 mm (about 4 in).
Is a guard the same as a handrail?
No. A guard is a barrier that stops people falling off an edge. A handrail is a rail you hold for support on stairs and ramps. A steel railing can do both jobs, but then it has to meet both sets of rules.
