A fixed steel ladder's key dimensions are its rung spacing, clear width between side rails, clearance behind the rungs, side rail extension above the landing, and the heights at which a cage and rest platforms become required. In Ontario, the workplace regulations fix several of these: rungs at least 15 cm from the wall, side rails extending 90 cm above the landing, a cage on ladders over 5 m, and rest platforms at no more than 9 m. Rung spacing and width are not given a number in those regulations, so designers take them from the project specification or a ladder standard such as ANSI A14.3 or the US OSHA rule.
This post collects the numbers in one place, says where each one comes from, and lists what should be on a ladder detail drawing. For the cage rules in depth, see our guide to fixed steel ladders with cages in Ontario.
Where steel ladder dimensions come from
No single document covers every dimension of a fixed ladder in Ontario. Four sources usually come into play:
| Source | What it covers | Applies to |
|---|---|---|
| R.R.O. 1990, Reg. 851, s. 18 (Industrial Establishments) | Vertical ladder, cage, rest platforms, side rail extension, rung clearance from wall | Workplaces such as factories, shops, offices and warehouses |
| O. Reg. 213/91, s. 84 (Construction Projects) | The same geometry, plus clear landings and sound rungs | Construction projects |
| 2024 Ontario Building Code, Article 3.6.1.6. and Supplementary Standard SB-8 | Design of the attachment and anchorage of ladders that give access to a roof | Roof access ladders |
| ANSI A14.3 or OSHA 29 CFR 1910.23 | Detailed geometry: rung spacing, clear width, clearances, step-across | Federally regulated workplaces in Canada (the Canada Occupational Health and Safety Regulations adopt ANSI A14.3 by reference); widely used as a design reference elsewhere |
The practical result: Ontario rules decide when you need a cage and platforms and how the ladder meets the landing, the building code decides how a roof ladder is anchored, and the detailed spacing numbers usually come from a ladder standard named in the specification. If your specification is silent, ask the designer which standard governs before the shop drawings are made.
Steel ladder dimension reference
The table below puts the common dimensions side by side. Ontario values are from Reg. 851 s. 18 and O. Reg. 213/91 s. 84. OSHA values are from 29 CFR 1910.23, given in the units OSHA uses with its own metric equivalents. OSHA is a US rule and does not apply to Ontario work, but many manufactured ladders and specifications are built around it.
| Dimension | Ontario regulations | OSHA 1910.23 |
|---|---|---|
| Ladder angle | Fixed access ladder must be vertical | Pitch greater than 90 degrees from horizontal not permitted |
| Rung spacing | Regular intervals (no number given) | 10 in to 14 in (25 cm to 36 cm), uniform |
| Clear width between side rails | Not specified | At least 16 in (41 cm) |
| Clearance behind rungs | Rungs at least 15 cm from the wall | At least 7 in (18 cm) from rung centreline to the nearest object behind |
| Clearance on the climbing side | Not specified | At least 30 in (76 cm) from rung centreline |
| Side rail extension above landing | 90 cm | At least 42 in (1.1 m) for through and side-step ladders |
| Cage required | Ladder extends more than 5 m above grade, floor or landing | New ladders over 24 ft need a ladder safety system or personal fall arrest system; cages stop counting as fall protection from November 18, 2036 |
| Cage start height | Not more than 2.2 m above the base | Not applicable |
| Cage above top landing | At least 90 cm | Not applicable |
| Rest platforms | At intervals of not more than 9 m, with the ladder offset at each | Not applicable in the same form |
Two notes on the table. First, a ladder that meets OSHA is not automatically compliant in Ontario: the cage and rest platform rules are different, and Ontario still calls for a cage over 5 m. Second, the Ontario rules exempt ladders on towers, water tanks, chimneys and similar structures that have a safety device to protect a worker who falls, such as a rail or cable ladder safety system.
Rungs: spacing, size and material
Rungs are where most ladder questions start.
- Spacing. Uniform spacing matters more than the exact number, because climbers set their rhythm on the first few rungs. A rung that is out of step at the top or bottom is a trip point. Where the specification follows OSHA, spacing falls between 25 cm and 36 cm, and many designs use a single value within that range for the full height.
- Size. Rungs are usually solid round or square bar welded between the side rails. The bar size is set by the design load, the clear width and the governing standard. It also has to be comfortable to grip, which rules out very small or very large bar. Your designer or the standard named in the specification sets the minimum.
- Slip resistance. Knurled, serrated or grit-coated rungs help on exterior and oily locations. Square bar set with a corner up is another approach.
- Material. Carbon steel is standard. OSHA requires metal ladders to be corrosion resistant or protected against corrosion, and in Ontario's climate exterior ladders are normally hot-dip galvanized. Stainless steel or aluminum show up in wet process areas.
The rungs also have to line up with the landing. The rung positions should be laid out from the landing down, so the step from the top rung onto the landing keeps the same rhythm as the rest of the climb.
Side rails, width and clearances
Side rails are commonly flat bar, angle or channel, sized for the ladder height and the spacing between wall brackets. The rails carry the rungs and transfer the load to the brackets.
Clear width is measured between the side rails. OSHA's 16 in (41 cm) is a minimum; many fabricated ladders are wider for comfort, especially where people climb with tool belts. If a ladder safety system will be added, the width has to allow for the rail or cable, and OSHA measures the minimum before the safety system is installed.
Clearance behind the rungs lets the climber's toes land on the rung. In Ontario, the rungs must be at least 15 cm from the wall. Watch for pipes, conduit, beams and parapet copings behind the ladder, because a single obstruction defeats the clearance at that height.
Clearance on the climbing side is the space for the climber's body. OSHA's 30 in (76 cm) from the rung centreline is a useful check for anything that projects toward the ladder, such as a door swing, a duct or a light fixture.
Side rail extensions give the climber something to hold while stepping on or off at the top. Ontario requires 90 cm above the landing. Where the climber walks through the rails onto a roof, the extensions are often flared apart and returned to the roof or parapet; where they step off to the side, the rails continue straight up. OSHA describes these as through ladders and side-step ladders, with its own limits on the flare and on the step-across distance from the rung to the landing.
Cages, platforms and roof hatches
Once a ladder climbs more than 5 m above the grade, floor or landing, Ontario requires a safety cage. The cage must start no more than 2.2 m above the base and continue at least 90 cm above the top landing, with openings to let the climber reach rest platforms and the top. Rest platforms are needed at intervals of not more than 9 m, and the ladder is offset at each platform so a fall from the upper section stops on the platform.
Cage hoop size, the spacing between hoops and the number of vertical bars are not set by the Ontario regulations. They come from the specification or the ladder standard, and they are shown on the shop drawings.
For roof access, Article 3.2.5.3. of the 2024 OBC requires buildings over 3 storeys with roofs sloped less than 1 in 4 to provide access to main roof areas, either by a stair or by a hatch at least 550 mm by 900 mm with a fixed ladder. The ladder must line up with the hatch so the climber's back clears the hatch frame and the side rails or a grab bar continue through the opening.
On chimneys, the OBC sets one more number: where access ladders are provided on chimneys, the rungs are steel or bronze built into the chimney walls, and rungs on external ladders begin at least 2.5 m above ground level, which keeps them out of casual reach.
Brackets and anchorage dimensions
Ladder geometry is only half the specification. The other half is how it holds onto the building. For any fixed ladder that gives access to a roof, the 2024 OBC sends you to SB-8, which sets:
- design loads of at least two 1.1 kN loads between any two consecutive attachments, plus ice, wind, impact and dead loads where they apply
- safety factors of at least 4 to 1 for components in normal use and 10 to 1 for components supporting a fall arrest system
- attachment and anchor bolts at least 12 mm in diameter
- attachment points no more than 3 m apart for a steel ladder with side rails
Bracket length is set by the 15 cm minimum rung clearance plus anything that projects from the wall, such as insulation, cladding or a parapet cap. On a new building, embed plates or blocking for the brackets should be planned before the wall goes up. On masonry, SB-8 warns against relying on expansion anchors without rated values; through-bolting is the usual answer.
What a ladder shop drawing should show
A clear ladder detail saves questions on site. Before fabrication, the shop drawing should show:
- overall height from the base to the top landing, measured on site where possible
- rung spacing, rung bar size and surface, and the position of the top rung relative to the landing
- clear width, side rail size and side rail extension details at the top
- bracket locations, bracket length, anchor type and size, and what each bracket fastens to
- cage hoops, vertical bars and the cage start and finish heights, where a cage is needed
- rest platform size, guards and the offset between ladder sections
- hatch or parapet details at the top, and any lockable climb guard at the base
- finish: galvanized, primed or painted
For how these drawings fit into the wider misc steel package, see miscellaneous steel detailing. If you are still deciding what kind of access you need, our overview of types of steel ladders in buildings and structures compares fixed ladders, ship ladders and stairs, and industrial steel stairs and roof access stairs covers the cases where a stair is the better choice.
Getting a steel ladder fabricated
We fabricate custom steel ladders, cages and platforms with CWB certified welding and shop drawings prepared in-house, and we can prime or galvanize them to suit the location. Engineering services are available where the anchorage needs to be designed. Installation is by your installer or contractor.
Send us the height, what the ladder fastens to, photos and any drawings for a free quote, and see our services for the rest of our miscellaneous steel work.
Frequently asked questions
What is the standard rung spacing on a fixed steel ladder?
Ontario's workplace regulations say rungs must be spaced at regular intervals but do not give a number. The US OSHA rule, which many ladder designs follow, requires rungs spaced 10 in to 14 in (25 cm to 36 cm) apart and uniform along the ladder. Confirm the value in your project specification.
How wide does a fixed steel ladder need to be?
OSHA requires a minimum clear width of 16 in (41 cm) between side rails on fixed ladders. Federally regulated workplaces in Canada follow ANSI A14.3 by reference. Ontario's Reg. 851 does not set a width, so the project specification or the designer sets it.
How far from the wall should a steel ladder be?
In Ontario, Reg. 851 and the construction regulation require rungs at least 15 cm from the wall. OSHA measures from the rung centreline and requires at least 7 in (18 cm) to the nearest object behind the ladder.
How far must ladder side rails extend above the landing?
Ontario requires the side rails of a fixed access ladder to extend 90 cm above the landing. OSHA requires 42 in (1.1 m) for through and side-step ladders.
