Bar Bending Schedule for Staircases (Dog-Legged & Straight Flight)

Staircases are one of the more geometrically involved members to schedule, because the main reinforcement follows a sloped waist slab rather than a flat one, and a dog-legged stair adds a crank where two flights meet at a mid-landing. This guide covers the bars in a typical staircase and how the dog-leg detail is scheduled.

Staircase types: a quick note

Two common layouts come up most often. A dog-legged staircase has two flights running in opposite directions with no gap between them in plan, connected by a mid-landing — the layout most residential and commercial stairs use. A straight-flight staircase runs in one direction only, with reinforcement that's simpler to schedule since there's no direction change to detail. The dog-legged case is the more involved one, so that's the focus of the worked example below.

Not to scale — illustrative only

The bars in a typical dog-legged staircase

• Main bars (waist slab). Follow the slope of each flight along the underside of the waist slab, similar in role to a slab's main bars but running along an incline rather than horizontally.
• Distribution bars. Run across the width of each flight, perpendicular to the main bars, tying them together — the same role as distribution bars in a flat slab.
• Crank at the mid-landing. Where a dog-legged stair's two flights meet, the main bar needs to change direction to continue from one flight's underside to the next, which is detailed as a crank (a multi-bend shape, broadly similar in principle to the cranked bars covered in our beam guide) rather than a sharp single bend.
• Landing bars. The mid-landing itself is typically reinforced like a small slab, with its own main and distribution bars tying into the flights on either side.

Worked example

A dog-legged staircase, two flights each 2.5m sloped length, 1.2m flight width, 12mm main bars at 150mm centres, 10mm distribution bars at 200mm centres, 25mm cover.

1. Main bar length (per flight). Sloped flight length plus a small anchorage allowance at each end — here, 2.5m + 2 × 50mm ≈ 2.6m.
2. Number of main bars. Flight width ÷ bar spacing, plus one: 1.2m ÷ 0.15m + 1 = 9.
3. The crank detail. The mid-landing crank geometry depends on the level difference and landing width in the actual design, so unlike the straight-run bars above, it's usually scheduled as shape code 99 with a fully dimensioned sketch rather than a standard formula — see our shape codes guide for when code 99 applies.
4. Distribution bars. Same logic as a slab — flight length ÷ spacing for quantity, flight width plus cover for cutting length.

Because the crank at the landing is project-specific, it's the one part of a staircase schedule that typically can't be reduced to a standard formula — everything else follows the same straight-bar logic as a slab.

Frequently asked questions

What is a dog-legged staircase?

A dog-legged staircase is a common staircase layout where two flights run in opposite directions, connected by a mid-landing, with no gap (well) between the flights when viewed from above — giving the stair its characteristic zig-zag or "dog-leg" shape in section.

What bars go into a staircase bar bending schedule?

A typical staircase schedule includes main bars running along the waist slab following the slope of each flight, distribution bars running across the width of the flight, and crank bars at the mid-landing where a dog-legged stair changes direction.

Why do staircase main bars need a crank?

The main bars in a dog-legged staircase crank at the mid-landing because the reinforcement needs to continue from the underside of one flight to the underside of the next, and the two flights sit at different levels connected by a landing, so the bar has to step between them rather than running in a single straight line.

This is an illustrative worked example, not a substitute for a checked, engineer-approved bending schedule. Staircase crank geometry in particular is highly project-specific — always take dimensions from the actual structural design.