Safe Access in Residential Design
Stairs That Don’t Fit the Rulebook
NCC 2022 Volume 2
Area of NCC Requirements:
- H5P1 – Safe Movement and Access
- H5D2 – Stairway and Ramp Construction
- ABCB HP Part 11.2 – Stairway Construction
The Challenge
Stair safety is governed by strict dimensional rules. The NCC sets minimum tread (going) depths at 240mm to ensure predictable and safe stride patterns.
But in a new residence in New South Wales, architectural constraints meant the stair leading to a bedroom had a going of only 190mm—50mm less than the DTS minimum.
A straight DTS solution wasn’t possible.
Why Stair Geometry Matters
The DTS stair dimensions aren’t arbitrary. They’re based on centuries of biomechanical research—starting with Blondel’s 17th-century “2R+G” rule—showing how stride length relates to comfort and safety.
While international codes allow smaller goings, consistency and safety measures become even more important when stepping outside DTS parameters.
The Solution
This performance solution assessed:
- Ergonomic safety
- Slip resistance and nosing performance
- Handrail placement for stability
- Lighting and visibility to mitigate risks
Through a combination of comparative DTS analysis and expert judgement, the reduced going was shown to meet the intent of H5P1.
Why This Matters
Bottom line:
Not every project can tick every box in the DTS checklist. But safety doesn’t have to be compromised. Performance solutions allow homes to achieve architectural vision while still delivering safe, compliant movement within buildings.
Performance Solutions Australia specialises in bridging that gap—balancing design aspirations with regulatory compliance.