Steel stairs and concrete stairs follow the same Ontario Building Code rules for rise, run, width, headroom, guards and handrails, so the choice comes down to weight, site conditions, schedule and how the stair will be used. Concrete suits short exterior steps at grade and stairs cast with a concrete building. Steel suits stairs that span between floors, stairs added to existing buildings, exterior stairs that must stay light on their footings, and projects that need the stair in early. In many commercial buildings the answer is both: steel pan stairs filled with concrete.
Steel vs concrete stairs at a glance
| Steel stairs | Concrete stairs | |
|---|---|---|
| Weight | Light for the span | Very heavy; needs substantial support |
| How it's built | Fabricated in a shop, installed in hours or days | Formed and poured in place, or precast and set by machine |
| Schedule | Install, then use | Forming, pouring and curing before full use |
| Spanning between floors | Natural fit, with slim stringers | Needs to be designed and cast with the structure |
| Exterior durability | Good when galvanized and drained | Good when the mix and finish suit freeze-thaw and salt |
| Noise | Can ring unless treads are concrete-filled, wood or dampened | Quiet and solid |
| Changes later | Can be unbolted, modified or replaced | Demolition |
| Look | Open, slim, industrial or modern | Solid, monolithic |
Same code rules, different construction rules
The dimensional rules in Section 9.8. of the 2024 Ontario Building Code apply whatever the stair is made of: private stairs can rise up to 200 mm with at least a 255 mm run, public stairs up to 180 mm with at least 280 mm, plus width, headroom, landing, guard and handrail rules. See Ontario Building Code rules for steel stairs for the full list.
Where the two materials differ is in how the code treats their construction:
- Steel stairs are designed for the loads. Article 9.8.9.1. requires stairs to be designed for 1.9 kPa where they serve a single dwelling unit (or a house with a secondary suite) and 4.8 kPa for other stairs. There are no prescriptive tables for steel stringers, so they are sized on the shop drawings or by an engineer.
- Exterior concrete stairs have support rules. Article 9.8.9.2. says exterior concrete stairs with more than 2 risers and 2 treads must be supported on unit masonry or concrete walls or piers at least 150 mm in cross-section, or cantilevered from the main foundation wall. Their foundations must meet the depth rules in Section 9.12.
- Cantilevered precast steps (Subsection 9.8.10.) must be designed for their loads, anchored to concrete foundation walls at least 200 mm thick, and protected during backfill and grading so frost in the soil underneath doesn't lift and damage the steps or the wall.
That last rule explains a familiar Ontario sight: precast front steps that have tilted, settled or pulled away from the house. Concrete steps are heavy and sit close to the ground, so frost and settlement act on them directly.
Exterior stairs: frost, salt and weight
For exterior stairs in Ontario, the deciding factors are usually what happens in winter.
Concrete exterior stairs:
- A large mass sitting on or near the ground, so frost heave and settlement can crack or tilt them unless the support is right
- Freeze-thaw cycles and de-icing salt can scale the surface and expose reinforcing steel over time
- Solid and quiet, with no rust to manage on the stair itself
- Hard to repair well once they start to fail; replacement usually means demolition
Steel exterior stairs:
- Much lighter, so they sit on a few posts and footings instead of a full foundation, and the footings can be taken below frost depth for your site
- Grating treads let snow and water through, and steel doesn't scale
- Need hot-dip galvanizing or a durable coating, and details that drain water
- Can be bolted together, removed and replaced without breaking anything
A common renovation is replacing failing concrete steps at a rear entrance, basement walkout or second-unit entrance with a steel stair on new footings. Our guide to exterior steel stairs covers design and finish in detail.
Interior and commercial stairs
Inside buildings, the choice is usually driven by the structure around the stair.
- Cast-in-place concrete stairs make sense when the building's frame is concrete and the stair is formed and poured with the floors. They're solid and quiet but tie the stair to the concrete schedule.
- Steel stairs suit steel-framed buildings, mezzanines, renovations and any stair added after the structure is up. They can be set early so trades have access between floors.
- Steel pan stairs combine the two: steel stringers with formed steel pans for the treads and landings, filled with concrete on site. They're the standard stair in many commercial and multi-unit stairwells because the steel installs quickly and the concrete fill gives a solid, quiet walking surface.
In houses, stairs between floors are rarely concrete, so steel usually competes with wood instead; see steel stairs vs wood stairs.
Weight and the structure underneath
Weight is easy to overlook. A concrete stair is far heavier than a steel stair of the same size, and all of that load goes into whatever supports it: foundation walls, slabs, piers or floor framing. For a new building that's simply designed in. For an existing building, a deck or an upper-floor addition, a concrete stair may need new foundations or strengthening that a steel stair doesn't. That alone often decides the question in renovations.
Is steel cheaper than concrete for stairs?
We don't publish prices, and neither material is cheaper everywhere. The cost drivers differ:
Concrete stairs:
- Formwork and labour on site, or precast units and the equipment to set them
- Foundations sized for a heavy stair
- Reinforcing steel, concrete and finishing
- Curing time before full use, which can hold up other work
- Demolition and disposal if you're replacing an old stair
Steel stairs:
- Layout, number of landings and stringer type
- Tread type: grating, checker plate, pans for concrete, or wood
- Guards and handrails
- Finish, especially galvanizing for exterior stairs
- Shop drawings, delivery and installation
As a rough rule, short exterior steps at grade lean toward concrete, and stairs that span, connect floors or go into existing structures lean toward steel. The way to know for your project is to compare quotes for the same layout, railings and finish. Our guide to what drives steel stair cost in Ontario explains how a steel stair quote is built.
Questions to settle before you choose
- Is the stair interior or exterior, and how exposed is it to salt and snow?
- What will support it, and can that support carry a concrete stair's weight?
- When is the stair needed in the construction sequence?
- Does it span between floors or sit at grade?
- How much noise is acceptable, and would concrete-filled pans or wood treads solve it on a steel stair?
- Is there a permit, and has the design been checked against the OBC?
Getting a steel stair quoted
We fabricate custom steel stairs and railings in our shop in Erin, with CWB certified welding and shop drawings prepared in-house, and deliver across the GTA and Ontario. Engineering services are available for projects that need them.
Send your drawings, photos or floor-to-floor measurements for a free quote. We fabricate and deliver the stair, and installation is by your installer or contractor. See our services for the full range of fabrication work we do.
Frequently asked questions
Is a steel staircase cheaper than a concrete staircase?
It depends on the stair. For a short set of exterior steps at grade, precast or poured concrete is often simplest. For a stair that spans between floors, has landings or goes into an existing building, steel usually avoids formwork, curing time and heavy foundations. Compare quotes for the same layout, railings and finish.
Which lasts longer, steel or concrete stairs?
Both can last decades if they're protected. Exterior concrete steps can scale and crack from freeze-thaw and de-icing salt, and precast steps can settle or pull away from the house. Exterior steel needs galvanizing or a durable coating and drainage so it doesn't rust.
Do concrete front steps need a foundation in Ontario?
Under the 2024 Ontario Building Code, exterior concrete stairs with more than 2 risers and 2 treads must be supported on concrete or masonry walls or piers at least 150 mm in cross-section, or cantilevered from the foundation wall. Their foundation depth must follow Section 9.12.
What are steel pan stairs?
Steel pan stairs have steel stringers and formed steel pans for treads and landings, which are filled with concrete on site. They're the common stair in commercial stairwells because the steel goes in early and the concrete gives a solid, quiet walking surface.
