Stair Nosing and Anti-Slip Requirements

What This Requirement Covers

Stair nosing and anti-slip requirements cover the design, construction and installation of stair treads, nosing strips and landing edges to reduce slip, trip and fall hazards on internal and external stairways. These requirements set minimum slip-resistance classifications for tread surfaces and nosing or edge strips, prescribe dimensional limits for treads and landings where nosings and slip-resistant surfaces are required, and ensure stair geometry does not increase accident risk. The aim is to protect building occupants, visitors and emergency services personnel by providing consistent, measurable levels of slip resistance and safe stair geometry across building types.

These provisions apply to designers, builders, product specifiers and certifiers for all building classes regulated under the National Construction Code (NCC) and associated ABCB Housing Provisions. They are relevant to both new construction and certain alterations where stair performance or occupant safety may be affected. Compliance typically relies on test results to Australian Standards (notably AS 4586 and related standards) and the NCC clauses and tables that specify minimum slip-resistance classifications and dimensional requirements.

Key Requirements

1. Slip-resistance testing - Stair treads, landing surfaces and nosing or landing edge strips must have a slip-resistance classification determined by testing in accordance with AS 4586 (Wet Pendulum Test or Oil-Wet Inclining Platform Test) as referenced in the NCC and ABCB Housing Provisions. (See NCC Volume One, Table D3D15; ABCB Housing Provisions, Table 11.2.4.)
2. Minimum classifications (typical) - The NCC and ABCB Housing Provisions set minimum classifications for dry and wet conditions in Tables D3D15 (Volume One) and Table 11.2.4 (Housing Provisions). Examples from those tables include:
3. Tread or landing surface: minimum P3 or R10 for dry conditions and P4 or R11 (or higher) for wet conditions where indicated (see NCC Volume One, Table D3D15 and ABCB Housing Provisions, Table 11.2.4).
4. Nosing or landing edge strip: minimum P3 (dry) and P4 (wet) in many applications (see NCC Volume One, Table D3D15; ABCB Housing Provisions, Table 11.2.4).
5. Nosing/landing edge coverage: Where a landing edge leads to a flight below, the landing must either have:
6. a slip-resistant surface for at least 190 mm measured from the stair nosing; or
7. a nosing strip with the required slip-resistance classification (ABCB Housing Provisions, 11.2.4(4); see also NCC Volume One D3D15).
8. Tread construction: Treads must have either a surface meeting the classification in Table D3D15 or a compliant nosing strip (NCC Volume One, D3D14 and D3D15 references). Treads intended for external or weather-exposed locations should be specified for wet-condition classifications.
9. Solid construction requirement: Stair treads in stairways more than 10 m high or connecting more than 3 storeys must be of solid construction (not mesh or perforated material) (NCC Volume One, D3D14(1)(f)).
10. Riser opening limitation: Risers must not have openings that permit a 125 mm sphere to pass between treads (NCC Volume One, Table D3D14 notes).
11. Dimensional requirements tied to nosing use: The general riser and going dimensions and landing sizes (e.g., landing length not less than 750 mm, landings gradient not steeper than 1:50) remain applicable where nosings and slip-resistant surfaces are used (NCC Volume One, D3D14, D3D15; ABCB Housing Provisions 11.2.5).
12. Referenced Australian Standards - Primary test standard: AS 4586:2013+ - Surface roughness and slip resistance (wet pendulum and other test methods) as cited by the NCC and Housing Provisions. Other related standards informing design or materials include AS 1428.1 (access and mobility features), AS 4663 (Slip resistance measurement of existing pedestrian surfaces), and guidance in the NCC and ABCB explanatory material. Always use the version referenced by the NCC edition in force.
13. NCC citations (examples):
14. NCC Volume One, Clause D3D14 - Riser and going dimensions, tread requirements.
15. NCC Volume One, Clause D3D15 and Table D3D15 - Slip-resistance classification and requirements for treads, nosings and landings.
16. ABCB Housing Provisions Standard 2022, Clause 11.2.4 and Table 11.2.4 - Slip-resistance classifications and landing/nosing specifics for housing.

Residential vs Commercial

1. Residential (Class 1/10 - houses, private garages, sheds and similar): Housing provisions (ABCB Housing Provisions) apply and explicitly reference AS 4586 classifications and the same nosing/landing coverage rules (for example, the 190 mm landing edge coverage option and Table 11.2.4 minimum classifications). Private stairways in sole-occupancy units are covered by the housing provisions when relevant (ABCB Housing Provisions 11.2.4, 11.2.5).
2. Commercial and other non-residential (Class 2-9): NCC Volume One clauses D3D14/D3D15 apply. Commercial, public and assembly uses generally require higher attention to wet-condition slip resistance (for example, P4 / R11 or higher for wet conditions) and may require landing sizes and nosing strip classifications suitable for higher traffic and emergency egress (see Table D3D15). Class 9a and 9b buildings contain additional dimensional requirements for landings and may impose stricter spatial requirements for stretcher movement and change of direction (NCC Volume One, D3D15).

In practice, the slip-resistance classification required often depends on anticipated surface condition - whether the surface is normally dry or normally wet/exposed to weather - so commercial/public areas exposed to weather or frequent wetting require higher wet-condition classifications than internal private residential stairs.

Exceptions and Exemptions

1. Where a landing edge has an alternative compliant nosing strip with the correct slip-resistance classification, the requirement to provide 190 mm of slip-resistant landing surface may be satisfied by that strip (ABCB Housing Provisions 11.2.4(4)).
2. Private stairways serving only non-habitable rooms (for example attics, storerooms not normally used) may be treated differently under some housing provisions. Check ABCB Housing Provisions 11.2.5(2) for specific contexts.
3. Where the NCC allows alternative solutions, performance-based evidence may be accepted in lieu of the prescriptive classifications. This typically requires test data, engineering judgment and approval by the relevant building certifier. Always document test results to AS 4586 and any performance evidence used.
4. Existing stairways undergoing alteration may be subject to state/territory repair and maintenance exemptions in some jurisdictions; however, where the work affects egress or safety, certifiers commonly require upgraded slip resistance to meet current minimums.

State and Territory Variations

1. The NCC is a national code, but each state or territory may have schedules or local amendments in NCC Volume One (Schedules 4-12) that modify or add requirements. Examples to check in the relevant jurisdiction:
2. Queensland - check Schedule 7 of NCC Volume One for any state-specific amendments that affect stair or ramp provisions.
3. New South Wales, Victoria, Western Australia, South Australia, Tasmania, Northern Territory and ACT - verify the state schedule in NCC Volume One and any state building authority guidance for slip-resistance requirements or acceptable test reports.
4. The ABCB Housing Provisions are nationally referenced for Class 1 and 10 housing, but some states adopt local guidance or additional requirements for external stairs, balconies and egress paths subject to weather. Always confirm with the local council or certifier whether state schedules or local amendments impose higher slip-resistance classifications or additional documentation.
5. Where local standards or tender documentation call for specific Australian Standard test methods or classification thresholds (for example, insisting on a minimum R11 in wet conditions for external steps), those prevail for that project alongside any state schedule requirements.

Practical Compliance Tips

1. Specify slip resistance by test classification, not by vague descriptions. Require manufacturers to supply a current test report to AS 4586 showing the P or R classification for the intended condition (dry or wet).
2. For external or weather-exposed stairs, design and specify for the wet-condition classification (e.g., P4 / R11 or higher) rather than dry-classification values.
3. Where a landing leads to a flight below, either provide at least 190 mm of compliant slip-resistant landing surface measured from the nosing or install a compliant nosing strip with documented AS 4586 classification.
4. Avoid perforated or mesh treads on stairways more than 10 m high or connecting more than 3 storeys; use solid treads as required by NCC Volume One, D3D14(1)(f).
5. Keep tread and riser variations within allowable tolerances: adjacent risers or goings must not vary by more than 5 mm, and the largest and smallest within a flight must not differ by more than 10 mm (NCC Volume One, D3D14). Inconsistent dimensions cause trips even if slip resistance is compliant.
6. For refurbishment projects, test existing surfaces using an accredited laboratory for AS 4663 or AS 4586 methods where appropriate. Replace or overlay treads/nosings where test results show classifications below the minimum required for the location.
7. Retain and supply test certificates and product data sheets to the building certifier at approval and handover. Include information on the test method, identifying the surface, the test classification (P or R), and whether the test was for dry or wet conditions.

Citations: NCC 2022 Volume One - Clause D3D14 and D3D15 (Tables D3D14 and D3D15); ABCB Housing Provisions Standard 2022 - Clauses 11.2.4, 11.2.5 and Table 11.2.4; AS 4586 (referenced test standard).