Building Codes in Australia: NCC by State on Chippy Tools

Footing Sizes & Site Classification (AS 2870)

Tue, 28 Jul 2026 00:00:00 +0000

The requirement

Before you dig, before you pour, someone has to work out how much your ground will move. Clay swells when it gets wet and shrinks when it dries. That movement is what cracks slabs and footings. So the NCC 2025 makes the ground under your house be classified — given a letter — using the standard AS 2870 (Housing Provisions, clause 4.2.2). AS 2870 is the Australian rule book for house footings and slabs.

Gutters & Downpipes: NCC Sizing Basics

Tue, 28 Jul 2026 00:00:00 +0000

The requirement

Gutters and downpipes carry the rain off the roof and away from the house. Get them too small and the water backs up, spills over, and ends up inside. The rule book — the National Construction Code, or NCC — sets out how to size them so that doesn’t happen (NCC 2025, Housing Provisions Part 7.4).

There are really three things to know: the one simple number you can carry in your head, the method the code uses to size everything, and the one job you hand off to someone else.

Minimum Ceiling Heights (NCC 2025)

Tue, 28 Jul 2026 00:00:00 +0000

The requirement

The rule book sets a smallest floor-to-ceiling height for every room in a house. It is not one number. How much headroom you need depends on what the room is used for (NCC 2025, Housing Provisions clause 10.3).

Here’s the quick version:

Where	Minimum ceiling height (NCC 2025)
Habitable rooms — bedroom, living, dining	2.4 m (2400 mm)
Kitchen, bathroom, laundry, toilet, pantry, storeroom, hallway, garage	2.1 m (2100 mm)
Over a stairway or ramp	2.0 m (2000 mm)

A habitable room is one people live in — bedrooms, living rooms, dining rooms and the like. The kitchen is not a habitable room, so it sits on the lower 2.1 m along with the wet rooms and utility spaces.

Minimum Roof Pitch (NCC 2025): Metal vs Tile

Tue, 28 Jul 2026 00:00:00 +0000

The requirement

Roof pitch is how steep your roof is. Lay it too flat and water sits on it instead of running off. So there’s a minimum — the flattest you’re allowed to go. The catch is that the minimum is set in two different ways depending on what you’re laying (NCC 2025, Housing Provisions Parts 7.2 and 7.3).

What you’re laying	Who sets the minimum pitch
Metal sheet roofing	The NCC — your profile’s minimum is in Figure 7.2.3
Roof tiles	Your tile maker — check AS 2050 / the manufacturer

Metal sheet roofing — the code fixes it. For metal sheet, the NCC itself sets the smallest pitch you can lay each profile at (clause 7.2.3, via Figure 7.2.3). It does not pass this off to AS 1562. Each profile has its own minimum:

Ramp Gradients (NCC 2025): Houses vs Access Ramps

Tue, 28 Jul 2026 00:00:00 +0000

The requirement

Before you pull a gradient number off the internet, sort out one thing: which rule even applies to your job. Most people quote the wrong one.

The famous NCC ramp clause is Volume One D4D12 (it points you to the standard AS 1428.1 for the detail). But D4D12 is for Class 2–9 buildings — units, shops, offices, that sort of thing. It does not cover a normal Class 1a house.

Shower & Wet Area Waterproofing (NCC 2025)

Tue, 28 Jul 2026 00:00:00 +0000

The requirement

Water is the thing that wrecks a bathroom. So the rule book — the National Construction Code (NCC) — says which bits of a wet area you have to seal, and how well. There are two levels of sealing:

Waterproof — a full barrier that water can’t get through. That’s your membrane.
Water-resistant — the surface stands up to water but isn’t a sealed barrier.

The NCC asks for waterproof in the wettest spots and water-resistant in the splash zones. Here’s where each one goes (NCC 2025, clause 10.2).

Stair Winders & Landings (NCC 2025)

Tue, 28 Jul 2026 00:00:00 +0000

The requirement

Turning a stair is where a lot of good work goes wrong. You’ve got two ways to do it: a landing — a flat platform you step onto mid-flight — or winders, the pie-shaped turning treads that fan around a corner. The rule book (NCC 2025, Housing Provisions Part 11.2) sets out how to do both safely.

Winders and the walking line. A winder is a tapered tread — wide on the outside of the turn, pinched to almost nothing on the inside. Its going (the depth you actually step onto) changes as you move across it, so the code says to measure it along a walking line — the path a person’s feet really take round the bend:

Balustrade Height Requirements: When Do You Need One?

Thu, 23 Jul 2026 00:00:00 +0000

The requirement

A balustrade — the rule book calls it a barrier — is there to stop someone falling off an edge. Two questions decide everything: do you need one, and how high does it have to be. The rule book covers both (NCC 2025, clause 11.3).

When you need one — the 1 m rule. You need a barrier wherever the surface you stand on is 1 m or more above the surface below it. Deck, balcony, landing, the edge of a raised floor — if the drop is a metre or more, a barrier goes in. Under a metre and you don’t have to fit one. This is the “1 m rule” you’ll hear on site, and it’s the heart of the balustrade rules.

How to Calculate Stairs: Rise, Run & Number of Steps

Thu, 23 Jul 2026 00:00:00 +0000

The method, in one line

Every stair job starts from two numbers you already have on site: the total rise (floor to floor) and the available run (how much floor length you have to fit the stair into). From those you work out the number of steps, the step height, the going and the total run. Then you check each one against the limits and the 2R+G rule.

Here are the numbers the rule book sets (NCC 2025, clause 11.2):

Maximum & Minimum Stair Riser Heights in Australia

Thu, 23 Jul 2026 00:00:00 +0000

The requirement

Riser height is the first stair number people get wrong. Too tall and the climb is hard work and a hazard. Too short and your toes catch on the way up. The rule book sets a top limit and a bottom limit for step height (NCC 2025, clause 11.2).

Riser (R) — the height of one step, measured from the top of one tread to the top of the next.

Riser limit (NCC 2025)	Value
Maximum riser (R)	190 mm
Minimum riser (R)	115 mm
Variation between risers in a flight	must be constant (small tolerance — verify)
Risers per flight before a landing	max 18

NCC 2025 Housing Provisions 11.2

On a normal job, the 190 mm top limit is the one that matters. A standard floor-to-floor height rarely gets you near the 115 mm bottom limit. So the job is almost always about adding enough steps to bring each one down under 190 mm.

NCC Stair Requirements: Riser, Going & the 2R+G Rule Explained

Thu, 23 Jul 2026 00:00:00 +0000

The rule, in one line

A stair needs to be steep enough to fit the space, but shallow enough to climb safely. The NCC sets this with three numbers — the riser, the going, and a formula that links them. They sit in the Housing Provisions (NCC 2025, clause 11.2).

Riser (R) — how tall each step is.
Going (G) — how deep each step is, measured from the front edge of one step to the front edge of the next.
2R+G — a comfort check. Two risers plus one going must land inside a set range.

Dimension	Limit (NCC 2025)
Riser (R)	max 190 mm · min 115 mm
Going (G)	max 355 mm · min 240 mm
2R + G	between 550 mm and 700 mm
Risers per flight	max 18 before a landing

NCC 2025 Housing Provisions 11.2

1 nosing

Every step in a flight must be the same height, and every step must be the same depth. The NCC only lets them vary by a tiny bit — because one odd step is where people trip.

The NCC for Chippies: Every Rule You Can Calculate (2026 Guide)

Thu, 23 Jul 2026 00:00:00 +0000

The National Construction Code (NCC) is the rule book for building work in Australia. It’s a big book. Most of it isn’t your job.

If you build houses, sheds, decks and carports, your whole job sits in one part of it. And nearly every rule in that part ends in a number you can measure.

This page is the map. It shows you where the house rules live, which numbers you can work out yourself, and where each one is written down. Then it points you to the article that does the maths.