Riser height (stairs)
Riser height is the vertical between stair treads, set under NCC Housing Provisions Part 11.2 at 115-190 mm residential, max 5 mm variation between risers.
Ask Chalkline about this →The riser height is the vertical distance between the top of one stair tread and the top of the next. Under ABCB Housing Provisions 2022 Part 11.2.2 it must sit between 115 mm and 190 mm on a standard residential stair, paired with a going of 240 to 355 mm and a 2R + G slope relationship between 550 and 700 mm (verified 2026-05-28).
The uniformity rule
The number that catches builders out is not the absolute range, it is the uniformity within a flight:
- Adjacent risers in a flight may vary by no more than 5 mm.
- The largest-to-smallest spread across all risers in a flight may not exceed 10 mm (verified 2026-05-28).
A flight that meets the 115 to 190 mm range but slips on uniformity will fail certifier inspection and pre-completion handover (PCI). The trip hazard from an uneven step is the reason: the foot calibrates to the first riser and expects the rest to match.
Flight limits
A flight must have no more than 18 risers and no fewer than 2. Once you hit 18, a landing is required before the next flight starts.
For a builder
- Set the rise from the total floor-to-floor early. Divide the floor-to-floor height by your target rise to get an integer number of risers; adjust within the 115 to 190 mm range so all risers are equal. This is the calculation that locks the design.
- Set out the stringer once. Re-measuring each riser as you go is where the 5 mm variation creeps in. Mark the stringer in one pass.
- Check the bottom riser after flooring goes down. Finished floor levels move; the bottom riser is the one most often left out of tolerance once the floor finish is installed.
Category: Stairs / NCC Housing Provisions.
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Last updated: 2026-05-28. Verified: 2026-05-28. Quarterly review for currency.