Building classifications explained: Class 1 to Class 10

By Brenscot Builders | Last reviewed September 2026

Almost every argument about what a building has to comply with comes back to one question: what class is it? Classification is the first decision in a building approval and it determines everything that follows — fire resistance, fire services, exits, accessibility, amenities, energy efficiency. Get it wrong and the building is designed against the wrong rulebook.

This is the full set, in plain English, with the industrial classes explained in more depth because that is where most of our work sits.

The short answer

The National Construction Code sorts buildings into ten classes by the purpose the building is designed, constructed or adapted to be used for — not by what it looks like, how big it is or what it is called. A warehouse is Class 7b. A factory or workshop is Class 8. An office is Class 5. A shed is Class 10a. A single building can hold several classifications at once, and each part has to comply with the requirements for its own class.

How a classification is decided

Part A6 of the Code sets out the mechanism, and four rules do most of the work.

Purpose decides it. The classification of a building, or a part of one, is determined by the purpose for which it is designed, constructed or adapted to be used. Not the name on the lease, not the zoning, not what the previous occupant did.

Each part is classified separately. Every part of a building must be classified according to its purpose and comply with all the appropriate requirements for that classification. This is why a warehouse with an office inside it is two classifications, not one.

Plant rooms follow the building. A room containing a mechanical, thermal or electrical facility that serves the building takes the same classification as the major part or principal use of the building or fire compartment it sits in. That rule does not apply to an electricity network substation.

Occupiable outdoor areas follow the part they belong to, unless another classification is more suitable.

There is one concession that comes up constantly on industrial jobs. Where a part of a building has been designed, constructed or adapted for a different purpose and is less than 10% of the floor area of the storey it is situated on, the classification of the other part of that storey may apply to the whole storey. Read that carefully: it is 10% of the *storey*, not of the building. And it does not apply where the minor use is a laboratory, a Class 9b early childhood centre, or a Class 2, 3 or 4 part. Where there is a conflict between what different parts require, the more stringent requirement applies.

The classes

Class 1 — dwellings

A Class 1 building is a dwelling.

Class 1a is a detached house, or one of a group of two or more attached dwellings separated by a fire-resisting wall, each being a building — a row house, terrace house, town house or villa unit.

Class 1b is a boarding house, guest house, hostel or the like that would ordinarily accommodate not more than 12 people and has a total floor area of not more than 300 m2 measured over the enclosing walls; or four or more single dwellings on one allotment used for short-term holiday accommodation.

Class 2 — apartment buildings

A building containing two or more sole-occupancy units, each of which must be a separate dwelling. The typical apartment building.

Class 3 — shared residential accommodation

A residential building providing long-term or transient accommodation for a number of unrelated persons. It covers boarding houses, guest houses, hostels, lodging houses and backpacker accommodation; the residential part of a hotel or motel; the residential part of a school; accommodation for the aged, for children, or for people with disability; the residential part of a health-care building that accommodates staff; the residential part of a detention centre; and a residential care building.

Class 4 — a dwelling inside a commercial building

A Class 4 part is a dwelling in a Class 5, 6, 7, 8 or 9 building if it is the only dwelling in the building. The caretaker's flat. If there are two or more dwellings, they are not Class 4 — they become Class 1, Class 2 or possibly Class 3, which is a materially different set of requirements.

This matters on industrial sites. A caretaker's residence attached to a warehouse is a Class 4 part, and a second one is not.

Class 5 — offices

An office building used for professional or commercial purposes. The office inside a warehouse is Class 5.

Class 6 — retail and services to the public

A shop or other building used for the sale of goods by retail or the supply of services direct to the public. It includes eating rooms, cafes and restaurants; the dining room, bar area, shop or kiosk part of a hotel or motel where that area is not an assembly building; hairdressers and barbers, public laundries and undertakers; and supermarkets, sale rooms, showrooms and service stations.

The distinction from Class 7b is the word retail. A showroom selling to the public is Class 6. A building displaying goods for sale by wholesale is Class 7b. A trade supplier that sells to both is a classification conversation worth having with the certifier early, because Class 6 and Class 7b do not carry the same requirements.

Class 7 — storage

A storage-type building, with two sub-classifications.

Class 7a is a carpark.

Class 7b is a building used for storage, or for the display of goods or produce for sale by wholesale. This is the warehouse classification. "Wholesale" means sale to people in the trades or in the business of on-selling goods and services to another party, including to the public.

Class 8 — process buildings

A process-type building. Class 8 covers a laboratory, and a building in which the production, assembling, altering, repairing, packing, finishing or cleaning of goods or produce for sale takes place.

The short version is "factory", but that undersells it. Laboratories are Class 8 despite often being small, principally because of their fire hazard. A workshop that repairs goods for sale is Class 8. The line between a Class 7b warehouse and a Class 8 factory is whether a process is carried out on the goods, and it is a line that moves when a tenant changes what they do in the building.

Class 9 — buildings of a public nature

Class 9a is a health-care building, including any parts set aside as laboratories, and includes a health-care building used as a residential care building. A laboratory that forms part of a Class 9a building is Class 9a, despite the general rule that laboratories are Class 8.

Class 9b is an assembly building, including a trade workshop or laboratory in a primary or secondary school. Theatres, cinemas, halls, churches, schools and early childhood centres sit here.

Class 9c is a residential care building.

Class 10 — non-habitable buildings and structures

Class 10a is a non-habitable building including a private garage, carport, shed or the like.

Class 10b is a structure that is a fence, mast, antenna, retaining wall or free-standing wall, or swimming pool or the like.

Class 10c is a private bushfire shelter.

Class 10a is the classification people reach for when they buy a kit shed, and it is the source of the most expensive misunderstanding in industrial construction. A Class 10a building is not a commercial warehouse and cannot lawfully be used as one without being designed, approved and certified for the commercial classification. See industrial shed or engineered warehouse.

Why classification drives everything else

On an industrial project, the class decides:

• Type of construction — whether the building is Type A, B or C, which follows from classification and rise in storeys, and which sets fire resistance levels. See Type A, B and C construction.
• Fire compartmentation — the floor area and volume limits that trigger fire walls. See fire walls and fire compartments.
• Fire services — hydrants, hose reels, sprinklers and the thresholds that bring each one in. See fire services.
• Egress — exit numbers, travel distances and exit widths.
• Accessibility — the access provisions and accessible carparking rates that apply to Class 5, 6, 7b, 8 and 9a. See parking, access and amenities.
• Sanitary facilities — the rates set by Part F4.
• Energy efficiency — whether the building has an envelope at all, which turns on whether there is a conditioned space. See insulation, condensation and Section J.

The classification traps on industrial projects

The office that grew. An office designed at under 10% of the storey and then extended past it changes the classification position for the storey. The 10% figure is not a design target; it is a threshold that should be checked against the final drawings. See the office inside a warehouse.

The tenant who changed the use. A Class 7b warehouse where the tenant starts assembling or repairing goods for sale has become a Class 8 building in substance. Under the Building Act 1975 it is an offence to make a change of BCA classification or use without approval, and a building cannot be occupied or used without a certificate of occupancy.

The mezzanine. Whether a mezzanine is a storey changes the rise in storeys, which changes the type of construction. That is a classification-adjacent decision with large consequences.

The showroom on the front. A trade counter open to the public can push part of a warehouse into Class 6. Worth resolving at design stage rather than at final inspection.

The caretaker's residence. One is a Class 4 part. Two is a different world.

Frequently asked questions

What class is a warehouse under the NCC?

Class 7b — a building used for storage, or for the display of goods or produce for sale by wholesale. An office inside it is Class 5, and a workshop area where goods are made or repaired for sale is Class 8.

What is the difference between Class 7b and Class 8?

Class 7b is storage and wholesale display. Class 8 is process — production, assembling, altering, repairing, packing, finishing or cleaning of goods or produce for sale, plus laboratories. If something is done to the goods in the building, it is likely Class 8.

Can one building have more than one classification?

Yes, and most industrial buildings do. Each part is classified according to its purpose and complies with the requirements for its own class. Where requirements conflict, the more stringent applies.

What is the 10 per cent rule?

Where a part of a building designed for a different purpose is less than 10% of the floor area of the storey it is on, the classification of the other part of that storey may apply to the whole storey. It does not apply where the minor use is a laboratory, a Class 9b early childhood centre, or a Class 2, 3 or 4 part.

Is a shed a Class 10a building?

A private garage, carport, shed or the like is Class 10a. A building used commercially for storing or wholesaling goods is Class 7b, regardless of how it is built or what it is called.

Who decides the classification?

The building certifier, as part of assessing the building development application, based on the purpose the building is designed, constructed or adapted to be used for. Confirm it with the certifier early — it is the decision every other requirement hangs off. See building certification in Queensland.

Sources

• National Construction Code 2022 Volume One, Part A6 Building classification: A6G1 (determining a building classification, including the 10% of a storey exemption and its limitations), A6G2 (Class 1), A6G3 (Class 2), A6G4 (Class 3), A6G5 (Class 4), A6G6 (Class 5), A6G7 (Class 6), A6G8 (Class 7), A6G9 (Class 8), A6G10 (Class 9), A6G11 (Class 10)
• Building Act 1975 (Qld), sections 110 (restriction on making a BCA classification or use change) and 114 (no occupation or use without a certificate of occupancy)

General information only

This article is general information, current as at September 2026, and summarises the Code rather than reproducing it. Classification depends on the specific building and its intended use. Confirm the classification of your building with a registered building certifier before relying on it.

Planning an industrial warehouse?

Talk to Brenscot about your site or your requirements. Call 0480 800 077, email enquiries@brenscot.com.au, or start an enquiry. You can also read how we work.