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

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.

Where the house rules live

The NCC comes in three books, called Volumes.

Volume One — big buildings: shops, offices and flats (Class 2 to 9). Not your job, mostly.
Volume Two — houses and small stuff: Class 1 and Class 10 buildings. This is your book.
Volume Three — water pipes and drains.

Volume Two is short on purpose. It only says what a job has to do — like “a stair must be safe to use.” It doesn’t give you the sizes. The sizes live in a companion book called the ABCB Housing Provisions. That’s the one with the step heights, step depths, ceiling heights and slab rules in it. So when someone quotes you a stair number “from the NCC,” they nearly always mean the Housing Provisions.

Volume One Class 2–9 — commercial & multi-residential buildings

Volume Two Class 1 & 10 — houses, sheds, garages & decks

ABCB Housing Provisions Standard

Stairways & barriers

11.2 Stairways max riser ~190 mm · verify
11.3 Barriers

Room heights

10.2 Room heights min ceiling height ~2.4 m · verify

Referenced standards (paid — not reproduced)

AS 1684 — Residential timber-framed construction — span tables
AS 2870 — Residential slabs and footings — site classification

Volume Three Plumbing and drainage — Plumbing Code of Australia

Class 1 is a home — a house or townhouse someone lives in (Class 1a), or a small boarding house (Class 1b). Class 10 is the stuff around a home that nobody sleeps in: sheds and carports (10a), fences, poles and retaining walls (10b), and private pools (10c). Once you know your class, you know which rules apply.

The good news: the code is free. The tables aren’t.

Here’s a handy thing to know. The NCC itself is free. It’s published under a licence called CC BY 4.0, which means anyone can read it, download it, even copy it — as long as they say where it came from. You can get the whole thing from the ABCB and pay nothing. That’s why this site can say what the code means in plain words, instead of hiding it behind a paywall.

But watch out. The NCC often points to other books called Australian Standards — and those cost money. AS 1684 (timber span tables), AS 2870 (slab and footing types) and AS 3600 (concrete cover) hold the exact numbers chippies want most. They’re not free. We don’t copy those tables. Instead we show you the method and let a calculator look up the answer. That’s the whole point of the app: it does the job of the table you’d otherwise have to buy.

Every rule you can put a number to

These are the house rules that come down to simple maths. Each one links to the article that works it out step by step.

Stairs and balustrades — the busiest group, and where most chippies meet their first code number.

NCC stair requirements: riser, going & the 2R+G rule — the three numbers that make a legal stair.
Maximum & minimum stair riser heights — how tall each step is allowed to be.
How to calculate stairs: rise, run & number of steps — turn a floor-to-floor height into a stair.
Balustrade height requirements: when do you need one? — the 1 m rule and where you measure from.

Coming next: framing and spans (how to read AS 1684 without buying it), roof pitch by material, wet-area waterproofing, and footings and slabs. This page grows as each group is added.

Work one out by hand

Take the most common job on site: making a stair fit a floor-to-floor height. Say the drop from one finished floor to the next is 2760 mm.

Find the fewest steps you can use. Each step (the riser) can’t be taller than a set limit. The long-standing figure is 190 mm (verify on the source site). 2760 ÷ 190 = 14.5. You can’t have half a step, so 14 isn’t enough. You need at least 15 risers.
Share the height out evenly. 2760 ÷ 15 = 184 mm per step. That’s under the 190 limit, and every step is the same height — which the code also asks for.

That’s the shape of almost every rule in Volume Two: a limit, a bit of division, and a check. The full stair walkthrough takes it further, to the step depth (the going) and the 2R+G comfort check.

Which edition applies to your job

We write against NCC 2025, the newest edition. But each state and territory starts using a new edition on its own timeline. Some are still on NCC 2022. On top of that, changes to the house rules are paused across the country until about 2029 — so the main numbers haven’t moved in years.

That’s good news, not bad. A step-height limit doesn’t change just because your state was slow to switch over.

For adoption dates, state changes, and a “which edition applies to me?” guide, see the Building Codes in Australia state hub.

Sources

NCC 2025 — ABCB, Volume Two and the Housing Provisions Standard. The primary source for every residential requirement above. Read it free at ncc.abcb.gov.au. (Building class definitions and the figures above are confirmed against NCC 2025, verified 2026-07-28.)
Licensing: NCC content is published under CC BY 4.0. Referenced Australian Standards are separate paid publications and are not reproduced here.

Frequently asked questions

What is the NCC in Australia?

The National Construction Code is one set of building rules for the whole of Australia. For houses and sheds, you mostly use Volume Two and the ABCB Housing Provisions, which sit under it.

What is NCC Volume Two?

Volume Two covers Class 1 and Class 10 buildings — houses, townhouses, sheds, garages, carports and decks. It says what each job has to do, then points to the Housing Provisions and the Australian Standards for the actual numbers.

Is the National Construction Code free to read?

Yes. The NCC is free to read and download from the ABCB. But the Australian Standards it points to — like the AS 1684 span tables and the AS 2870 slab types — cost money and are not free.

What is a Class 1 building under the NCC?

A Class 1a building is a house or townhouse — one home. Class 1b is a small boarding house. Class 10 is a building nobody sleeps in, like a shed, carport, fence or retaining wall.

Do the same NCC rules apply in every state?

The rules are national, but each state starts using a new edition at its own pace and adds its own changes — pool fences, bushfire, wet areas. Always check with your state authority and certifier.