Balustrades and stairs: the NCC numbers that matter

Decks, balconies and stairs come up again and again at inspections. The common problems are a balustrade a few millimetres short, a gap a child could get through, or risers that change height partway up the flight. This guide covers the NCC rules for houses and Class 10 structures, with the clause for each point.

Which edition? NCC 2022 applies in NSW, QLD, SA, TAS and the NT. NCC 2025 applies in WA, VIC and the ACT from 1 May 2026. The key numbers below are the same in both editions.

Where the rules are

• NCC 2022 Volume Two H5P1 and H5P2: the performance requirements for safe movement and fall prevention.
• H5D2: stairways and ramps, through ABCB Housing Provisions Part 11.2.
• H5D3: barriers and handrails, through Housing Provisions Part 11.3.
• Glass balustrades: H1D8. Balustrade glazing is covered by AS 1288 (the NCC 2022 references the 2021 edition) under H1D8(2)(b)(ix). We cite this Standard and don't reproduce it.
• Loads: AS/NZS 1170.1, for barriers (11.3.4(11)) and stairs (11.2.2(1)).

Key requirements: barriers (balustrades)

1. When you need one (HP 11.3.3): a continuous barrier is needed along any trafficable surface where someone could fall 1 m or more to the surface below. That includes stairs, ramps, floors, decks, balconies, verandahs and roof areas with general access. A retaining wall only needs one if it is part of a path of access to the building.
2. Height (HP 11.3.4(2) and (3)):
   • At least 865 mm above the stair nosings or ramp floor.
   • At least 1 m above the floor of a deck, balcony, landing, verandah or corridor.
   • A landing barrier can stay at 865 mm along the inside edge of a landing where that section is no longer than 500 mm.
   • A transition zone is allowed where the height steps up from the stair to the landing.
3. Openings (HP 11.3.4(4)): no opening may let a 125 mm sphere through. On stairs, measure above the line of the nosings.
4. Gap at the edge (HP 11.3.4(5) and (6)): where the barrier is fixed to the face of a deck or landing, the horizontal gap between the edge and the barrier is no more than 40 mm.
   • NCC 2019 difference: this rule is new in NCC 2022. It was not in 2019 clause 3.9.2.3.
5. Climbable rails (HP 11.3.4(8)): where the fall is more than 4 m, horizontal elements between 150 mm and 760 mm above the floor must not help a child climb.
6. Wire and glass:
   • Wire balustrades are deemed to meet the opening rule only if they are built to 11.3.6.
   • Glass barriers must also meet H1D8 (11.3.4(10)).
7. Bedroom windows (HP 11.3.7): this applies where the floor is 2 m or more above the ground outside and the window opening is less than 1.7 m above the floor.
   • The openable part needs a restrictor or a screen that stops a 125 mm sphere and resists a 250 N outward push.
   • A release must be child resistant. If the restrictor or screen can be overridden, an 865 mm barrier is also needed.

Key requirements: stairs and handrails

1. Risers and goings (HP 11.2.2 and Table 11.2.2a):
   • Each flight has 2 to 18 risers.
   • For ordinary (non-spiral) stairs, risers are 115 to 190 mm and goings 240 to 355 mm.
   • The 2R + G total is 550 to 700 mm.
   • Spiral stairs and stairs to rarely used non-habitable rooms have their own limits.
2. Keep them constant (HP 11.2.2(1)(c)): adjacent risers or goings can vary by no more than 5 mm, and the largest and smallest in a flight by no more than 10 mm.
3. Open risers (HP 11.2.2(1)(d)): the gap between treads must not let a 125 mm sphere through.
4. Landings (HP 11.2.5):
   • At least 750 mm long, with a gradient no steeper than 1:50.
   • Needed where a doorway opens onto a stair that drops more than 3 risers or 570 mm.
5. Slip resistance (HP 11.2.4): treads, nosing strips and ramps need a slip-resistance classification tested to AS 4586. Wet areas such as outdoor stairs need a higher class than dry ones (Table 11.2.4).
6. Handrails (HP 11.3.5):
   • At least one side, for the full length of the flight.
   • The top is at least 865 mm above the nosings, and the rail is continuous with nothing that breaks a handhold.
   • Not required where the stair changes level by less than 1 m, or on landings.

NCC 2025 changes:

• Fixed platforms, walkways, stairs and ladders for Class 10b structures can follow AS 1657 instead (11.2.7, 11.3.3(2)(c), 11.3.5(2)(d)).
• There are new concessions for threshold, step and kerb ramps (11.2.3(c), 11.2.4(3)).
• NCC 2019: the same topics sat in Parts 3.9.1 and 3.9.2.

How the states differ

• All states and territories: the Housing Provisions 2022 and 2025 schedules list no state variation to Parts 11.2 or 11.3. The rules above apply nationally. The main difference is the edition: WA, VIC and the ACT are on NCC 2025, and the rest are on NCC 2022. NSW, QLD, SA and TAS move to NCC 2025 from 1 May 2027. The NT has not announced a date.
• Pools: pool barriers are different, and each state has its own law for them. Ask the app with your state set.
• Livable housing: where Part H8 applies, step-free entry and path rules may affect where a stair or ramp goes. Part H8 doesn't apply in NSW.

Ask the app

Photograph your balustrade or stair and upload it, or ask:

• "How high does a deck balustrade need to be?"
• "Is a balustrade needed if my deck is 900 mm off the ground?"
• "What's the maximum riser height for house stairs?"
• "Can I use horizontal balustrade rails on a first-floor balcony?"
• "Do I need a handrail on a 3-step stair?"

Ask a carpentry question · Builder · Glazing

Related checklists

• Decks, balconies & balustrades: new house (plan required)
• Decks, balconies & balustrades: renovation / extension (plan required)
• Stairs (Class 1): new house (plan required)
• Stairs (Class 1): renovation / extension (plan required)
• Windows, doors & glazing: new house (plan required)
• Related guides: Wet-area waterproofing · Smoke alarms

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This is general guidance, not a compliance check. Always check your approved plans and the edition that applies to your permit, and confirm details with your certifier or building surveyor.

Based on content from the National Construction Code 2022 and 2025 (NCC Volume Two and the ABCB Housing Provisions), provided by the Australian Building Codes Board under the CC BY 4.0 licence. The ABCB does not endorse this guide. The standards the NCC references are cited and explained in our own words, not reproduced.