NCC stairs, balustrades and handrails: Part H5 explained

TL;DR

NCC 2022 Part H5 governs stairs, balustrades, and handrails for Class 1 homes. A barrier is required wherever a fall of 1 m or more is possible: minimum 865 mm above stair nosings, 1 m above balcony and deck floors. Openings must not pass a 125 mm sphere. Risers sit between 115 mm and 190 mm, goings between 240 mm and 355 mm, no more than 18 risers per flight. Balustrade height and stair geometry are two of the most common reasons a PCI fails and triggers re-inspection fees. The climbability zone (150 mm to 760 mm above floor, no horizontal elements where fall exceeds 4 m) is the one builders most often overlook on high deck and second-storey work.

In plain English

Part H5 of NCC 2022 Volume Two sets the minimum requirements for safe movement in and around Class 1 residential buildings (houses, duplexes, townhouses, Class 1b accommodation) and Class 10a structures. The detail lives in two documents read together: Part H5 itself (the performance requirements) and Part 11 of the ABCB Housing Provisions Standard 2022 (the deemed-to-satisfy numbers). Most certifiers and building surveyors assess compliance against Part 11.

Part H5 has two performance requirements:

H5P1 covers stairways and ramps: safe gradients, slip-resistant treads, adequate landings, suitable handrails where needed for stability.
H5P2 covers fall prevention barriers: continuous barriers to prevent falls of 1 m or more from floors, balconies, decks, and rooftops; barriers strong enough to withstand foreseeable impact; openings that restrict passage of children.

Most residential work uses the deemed-to-satisfy path through Part 11 of the Housing Provisions. Where the design can’t meet DTS (heritage stair geometry, architectural balustrading with unusual proportions), the alternative is a Performance Solution backed by an engineer’s report (verified 2026-05-07 via ncc.abcb.gov.au).

What it requires

Barriers (balustrades)

When a barrier is required

A continuous barrier is required wherever it is possible to fall 1 m or more from the trafficable surface to the surface below (Housing Provisions clause 11.3.3(1)). This catches stairways, ramps, corridors, balconies, decks, verandahs, mezzanines, access paths, and rooftop spaces with general access (verified 2026-05-07 via ncc.abcb.gov.au/editions/ncc-2022/adopted/housing-provisions/11-safe-movement-and-access/part-113-barriers-and-handrails).

Minimum heights

Location	Minimum barrier height
Along a stairway or ramp	865 mm above stair nosings or ramp floor
Landings, balconies, decks, corridors, mezzanines	1 m above the floor
Short landing edge directly serving stairs (barrier length 500 mm or less)	865 mm acceptable

Clause references: Housing Provisions 11.3.4(2)(a) and (b).

Opening restrictions (the 125 mm sphere test)

Openings in a barrier must not permit a 125 mm sphere to pass through (clause 11.3.4(4)). On stairways the measurement is taken above the nosing line of the treads, not from the floor.

The gap between the base of a face-mounted barrier and the edge of the trafficable surface must not exceed 40 mm measured horizontally (clause 11.3.4(5)). This is a common inspection issue: balustrades post-fixed to the face of a deck frame often leave a gap larger than 40 mm if the fixing height isn’t checked at install.

Climbability restriction

Where a fall exceeds 4 m, horizontal elements within the barrier between 150 mm and 760 mm above the floor must not facilitate climbing (clause 11.3.4(8)). This applies to decks, mezzanines, and second-storey balconies where the fall to the ground exceeds 4 m. Horizontal pool fence rails, horizontal batten spacings, and horizontal glass rails within that zone all fail this test.

Below 4 m fall height, horizontal elements are permitted (subject to the 125 mm sphere rule).

Non-habitable spaces

For barriers serving non-habitable rooms (storerooms, garages, attics), openings may permit a 300 mm sphere or use rails with openings not exceeding 460 mm (clause 11.3.4(7)). This concession doesn’t apply to any barrier where a child would reasonably have access.

Handrails

When required

A handrail must be provided to at least one side of a stairway or ramp where the change in elevation is 1 m or more (Housing Provisions clause 11.3.5(1)). The handrail must extend the full length of the flight or ramp.

Handrails are not required for:

Elevation changes of less than 1 m
Landings (the floor surface between flights)
Winders where a newel post is provided at the landing point

Height

The top surface of the handrail must be not less than 865 mm vertically above the nosings of the stair treads or the ramp floor surface (clause 11.3.5(1)(c)). No maximum height is specified in the Housing Provisions.

Graspability

A handrail must be continuous and free of obstructions that would break a handhold, except for newel posts or ball-type stanchions at the top and bottom of the flight (clause 11.3.5(1)(d)).

Stair geometry

The dimensional limits for stair construction sit in Part 11.2 of the Housing Provisions. The ABCB Housing Provisions Standard 2022 holds the authoritative table (Table 11.2.2a for standard stairs).

Standard stairs (not spiral)

Dimension	Minimum	Maximum
Riser height (R)	115 mm	190 mm
Going (tread depth, G)	240 mm	355 mm
Slope relationship (2R + G)	550 mm	700 mm

Spiral stairs

Dimension	Minimum	Maximum
Riser height	140 mm	220 mm
Going	210 mm	370 mm
Slope relationship	590 mm	680 mm

Non-habitable rooms (storeroom, attic access): riser 130 to 225 mm, going 215 to 355 mm. Only stair construction, not guest or occupant traffic (clause 11.2.2(2)).

Flight limits and uniformity

Each flight: minimum 2 risers, maximum 18 risers (clause 11.2.2(1)(a)).
Adjacent risers and goings may vary by no more than 5 mm; the spread between the smallest and largest within a flight must not exceed 10 mm (clause 11.2.2(1)(c)).

Landings

A landing is required when the level change exceeds 3 risers or 570 mm (clause 11.2.5). Minimum landing length: 750 mm (600 mm for non-habitable spaces). Gradient: not more than 1:50. A door opening onto a stairway requires a landing where that level change applies.

Winders

Maximum 3 consecutive winders in place of a quarter landing.
Maximum 6 consecutive winders in place of a half landing.

Slip resistance (Table 11.2.4)

Surface	Dry condition	Wet/exposed condition
Stair treads	P3 or R10	P4 or R11
Ramps (1:8 gradient)	P4 or R10	P5 or R12

External stairs and any treads exposed to rain or wet underfoot conditions need the wet classification. Timber decking, tiled treads, and polished concrete steps all need to be checked against these slip ratings.

(All stair geometry dimensions verified 2026-05-07 via ncc.abcb.gov.au/editions/ncc-2022/adopted/housing-provisions/11-safe-movement-and-access/part-112-stairway-and-ramp-construction.)

What it doesn’t cover

Pool fencing: pool barriers for swimming pools deeper than 300 mm are covered under NCC 2022 Part H7 by reference to AS 1926.1 and AS 1926.2, not Part H5. Note: Queensland and the Northern Territory regulate pool safety under state legislation, not the NCC (verified 2026-05-07 via ncc.abcb.gov.au/editions/ncc-2022/adopted/volume-two/h-class-1-and-10-buildings/part-h7-ancillary-provisions-and-additional-construction-requirements).
Class 2 to 9 buildings (apartments, offices, commercial): stair requirements for those sit in NCC Volume One Part D.
Stair width for Class 1 buildings: NCC Volume Two and the Housing Provisions do not specify a minimum stairway width for Class 1 buildings (verified 2026-05-07 via ncc.abcb.gov.au/faq/stairways-barriers-and-handrails).
Livable housing accessibility (Part H8): grab rails, hobless showers, and wider doorways for accessibility are in Part H8, not H5.

Practical implications

What to check before locking the design

Deck or balcony height above natural ground: if the finished floor level is 1 m or more above the surface below, a balustrade is mandatory. Confirm early: changing framing height after the slab is poured is expensive.
Fall height above 4 m: second storey decks and mezzanine voids commonly exceed 4 m. A horizontal rail or batten in the 150 to 760 mm zone fails the climbability test. Design a vertical or raked balustrade from the start.
Stair geometry locked before framing: risers and goings are set by stair stringer height and slab-to-slab dimensions. Lock the geometry before structural framing is completed. Late changes to floor-to-floor heights force stair rebuilds.
Slip resistance spec on external treads: confirm the slip rating with the tiler or finishes subbie before material procurement. Changing tread finish after installation is a PCI hold.

Common inspection failures at PCI

These are the H5 issues that generate re-inspection fees:

Defect	Why it fails
Balustrade under 1 m on deck or balcony	Finished height falls short after topping (tile or decking adds height to floor, not to balustrade)
Face-mount gap over 40 mm	Balustrade fixed to outside face of deck joist without checking gap at top of floor level
125 mm sphere passes through baluster spacing	Spacing set by eye or with pre-cut spacers, not measured against the test sphere dimension
Horizontal rail within 150 to 760 mm zone on high deck	Decorative feature rail specified without checking fall height
Riser variation over 5 mm between adjacent treads	Inconsistent stringer setting or differential shrinkage in timber treads
External timber treads with P3 slip rating only	Smooth hardwood decking used on external treads without grip strips or texture
Handrail not continuous to full flight length	Handrail terminates at first or last newel without extending to the full nosing line

Tolerances and acceptance

Workmanship tolerances for stair construction (riser height variation, stringer squareness, handrail fixing strength) are specified in the HIA Guide to Materials and Workmanship. HIA membership is currently deferred; verified numerical values for stair tolerances will be added when access is available. [HIA-031]

The NCC provides maximum dimensional limits (riser 115 to 190 mm, going 240 to 355 mm) and uniformity limits (adjacent risers within 5 mm, spread within flight 10 mm). The HIA Guide specifies workmanship acceptance criteria for PCI inspections.

Source link

ABCB Part H5 Safe movement and access: https://ncc.abcb.gov.au/editions/ncc-2022/adopted/volume-two/h-class-1-and-10-buildings/part-h5-safe-movement-and-access
ABCB Housing Provisions Part 11: https://ncc.abcb.gov.au/editions/ncc-2022/adopted/housing-provisions/11-safe-movement-and-access

References

Australian Building Codes Board, Part H5 Safe movement and access, NCC 2022 Volume Two. https://ncc.abcb.gov.au/editions/ncc-2022/adopted/volume-two/h-class-1-and-10-buildings/part-h5-safe-movement-and-access (verified 2026-05-07).
Australian Building Codes Board, Part 11 Safe movement and access, ABCB Housing Provisions Standard 2022. https://ncc.abcb.gov.au/editions/ncc-2022/adopted/housing-provisions/11-safe-movement-and-access (verified 2026-05-07).
Australian Building Codes Board, Part 11.2 Stairway and ramp construction, ABCB Housing Provisions Standard 2022. https://ncc.abcb.gov.au/editions/ncc-2022/adopted/housing-provisions/11-safe-movement-and-access/part-112-stairway-and-ramp-construction (verified 2026-05-07).
Australian Building Codes Board, Part 11.3 Barriers and handrails, ABCB Housing Provisions Standard 2022. https://ncc.abcb.gov.au/editions/ncc-2022/adopted/housing-provisions/11-safe-movement-and-access/part-113-barriers-and-handrails (verified 2026-05-07).
Australian Building Codes Board, Stairways, barriers and handrails FAQ, NCC. https://ncc.abcb.gov.au/faq/stairways-barriers-and-handrails (verified 2026-05-07).
Australian Building Codes Board, Part H7 Ancillary provisions and additional construction requirements, NCC 2022 Volume Two. https://ncc.abcb.gov.au/editions/ncc-2022/adopted/volume-two/h-class-1-and-10-buildings/part-h7-ancillary-provisions-and-additional-construction-requirements (verified 2026-05-07).

NCC 2022 Volume Two: the full residential code overview including H5 in context
ABCB Housing Provisions: the DTS document where stair and balustrade dimensions live
NCC: what the National Construction Code is and how it works
AS 3740 wet area waterproofing: the parallel H4 compliance requirement for adjacent wet areas
Performance solution: the alternative path when DTS geometry doesn’t fit
Chippy: the trade building the stairs and framing for balustrades
Tolerance: what workmanship tolerance means in a building context
PCI (Practical Completion Inspection): where stair and balustrade defects are most commonly found