What are the maximum riser and minimum going dimensions for stairs in a new house?
For a conventional (non-spiral) stairway in a new home, Table 11.2.2a sets the dimensional limits: [1]
- Riser: maximum 190 mm, minimum 115 mm
- Going: minimum 240 mm, maximum 355 mm
- Slope relationship (2R + G): between 550 mm and 700 mm
Spiral stairs have their own column in the table: riser 140 to 220 mm, going 210 to 370 mm, 2R + G between 590 and 680 mm. [1]
Consistency within a flight matters as much as the limits. Adjacent risers, and adjacent goings, must not differ by more than 5 mm, and the largest and smallest riser (or going) in the flight must not differ by more than 10 mm. [1]
A stairway serving only a non-habitable room such as an attic or storeroom that is not in regular use may instead use Table 11.2.2b, which permits a riser up to 225 mm and a going down to 215 mm. [1]
These values are unchanged in NCC 2025, so the edition transition does not affect stair design. In Tasmania, NCC 2022 (Amendment 2) is the operative edition until 30 April 2027. [1]
- 1NCC 2022 Volume Two — ABCB Housing Provisions11.2.2 and Table 11.2.2a — Riser and going · p. 291
This answer is for professional reference only and does not replace a registered building surveyor or certifier. The operative edition of the NCC differs by jurisdiction and changes over time. Verify against the current code for your jurisdiction before relying on it.