A steel staircase is a structure where comfort and safety come down to a handful of numbers. A 3–4 cm error in the rise makes climbing tiring, and the wrong tread surface turns outdoor stairs into an ice rink at the first thaw. Here is what to settle before fabrication starts.
Types and what they suit
- Portable ladders — the simplest, from tube or angle; roof, cellar or equipment access.
- Fixed vertical ladders — wall-mounted, with a safety hoop above a certain height; standard on industrial sites.
- Stringer stairs — full staircases with treads; the only type comfortable for daily use.
- Spiral stairs — for tight floor plans; compact, but awkward for carrying anything.
- Access platforms and walkways — stairs plus a maintenance platform, usually with railings and expanded metal decking.
The dimensions that make stairs comfortable
A simple rule works for stringer stairs: twice the rise plus the going should come to roughly 60–64 cm. In practice that means a 16–19 cm rise with a 27–30 cm going. Stairs with a 22 cm rise and a 22 cm going technically exist, but climbing them is hard work and descending is worse.
The pitch should be 30–40°. Steeper than 45° is a ladder, something you climb down facing backwards. Flight width for a house starts at 80 cm, with 90–100 cm being comfortable; technical stairs manage at 60–70 cm.
One more rule people remember too late: every step in a flight must be identical. A difference of even 1–2 cm on the last step is a classic cause of falls, because the foot settles into a rhythm.
Stringers and frames
The load-bearing element is either a stringer, with treads sitting on top of a sawtooth beam, or a pair of side beams with treads let in between them. The stringer looks lighter and is usually simpler to build; side beams look neater from the side and suit stairs that are on display.
Typical sections for domestic stairs: a stringer from 100×50×3 square tube or channel, treads framed in 40×40 angle or 40×20 tube. Stairs in a workshop or on a walkway are sized for the load by an engineer.
Tread surfaces
- Chequer plate 3–4 mm — the most common: stiff, repairable, inexpensive.
- Expanded metal — sheds water and dirt, works well outdoors, less slippery in winter.
- Welded grating — the industrial standard for walkways and platforms; the safest option and the dearest.
- Timber or concrete on a steel frame — the interior approach, where steel is only the structure.
Plain sheet without a pattern is a poor choice outdoors: it turns slippery in winter, and no coating changes that.
Railings and handrails
A handrail is needed from three steps up, and railings wherever the drop exceeds 45–50 cm. Standard railing height is 90–100 cm; where children use the stairs, the infill runs vertically at a spacing nobody can squeeze through, with no horizontal members that work as a ladder.
A handrail has to be grippable: 40–50 mm tube fills the hand, while 40×40 square with sharp edges does not. A detail nobody notices until the stairs are in use.
Material and finish
Structural steel with powder coating is the standard for indoor and most outdoor stairs. Aggressive environments and food production call for stainless: dearer, but with no coating and no maintenance. Hot-dip galvanizing suits stairs that live outdoors for years, often with paint over the top.
Whatever the finish, welds are dressed before coating — untreated seams are where rust appears first.
When to have them made
A portable or simple fixed ladder is realistic to weld yourself. A staircase is a different job: the height has to be divided into identical steps, the pitch held and the stringer geometry kept true. An error in setting out means the last step differs from the rest — and that is felt every day.
We build stairs, ladders, platforms and railings as steel structures: the flight is calculated for your floor-to-floor height, cut and welded in our own shop, coated and installed on site. Send us the floor-to-floor height and the space available in plan — that is enough for a first quote.
