Understanding the NCC
The National Construction Code (NCC) sets out the minimum technical requirements for new buildings (and new building
work in existing buildings) in Australia. In doing so, it groups buildings1 by their function and use. These groups are assigned
a classifcation which is then how buildings are referred to throughout the NCC. This information is crucial for all NCC users.
The following is a general representation of the building classifcations in the NCC. It is based on a national perspective
and does not address any State or Territory variations2.
1 In this document, a building may also refer to a structure such as swimming pool.
2 State and Territory variations and additions to the NCC are located in the NCC. The NCC is available at the ABCB website.
Building classifcations are labelled “Class 1” through to
“Class 10”. Some classifcations also have sub-classifcations,
referred to by a letter after the number (e.g. Class 1a).
Class 2 to 9 buildings are mostly covered by Volume One of
the NCC, and Class 1 and 10 buildings are mostly covered
by Volume Two of the NCC. Volume Three of the NCC refers
to all building classifcations.
A building may have parts that have different uses. In most
cases, each of these parts are classifed separately.
A building (or part of a building) may also have more than
one use and may be assigned more than one classifcation.
What is an SOU?
A sole occupancy unit (commonly known as a SOU)
is defned in the NCC as part of a building for occupation
by an owner/s, lessee, or tenant, to the exclusion of
any other owner/s, lessee, or tenant. So put simply,
it is a space with an exclusive use in a building.
SOUs can be located in a number of different classifcations.
• A residential apartment or ﬂat.
• A self-contained unit.
• A suite of rooms in a hotel or motel.
• A shop in a shopping centre.
All NCC volumes: Part A6
© Commonwealth of Australia and the States and Territories of Australia 2020, published by the Australian Building Codes Board.
The material in this publication is licensed under a Creative Commons Attribution—4.0 International licence, with the exception of third
party materials and any trade marks. It is provided for general information only and without warranties of any kind. More information
on this CC BY licence is set out at the Creative Commons Website. For information regarding this publication, see www.abcb.gov.au.
Class 4 part of a building
A Class 4 part of a building is a sole dwelling or residence
within a building of a non-residential nature. An example of
a Class 4 part of a building would be a caretaker’s residence
in a storage facility. A Class 4 part can only be located in
a Class 5 to 9 building.
If so, then it is likely to be a Class 4 part of a building.
There can only be one Class 4 part in a building.
A Class 4 part cannot be located in a Class 1, 2
or 3 building.
Is it the only residence in the building?
Class 5 buildings
Class 5 buildings are offce buildings used for professional
or commercial purposes.
Examples of Class 5 buildings are offces for lawyers,
accountants, government agencies and architects.
When is a general medical practitioner’s
offce not a Class 5 building?
Generally, a general medical practitioner’s offce will be
a Class 5 building. However, if any medical treatment
administered leaves patients unconscious or non-ambulatory,
then the building would be considered a health-care building
(as defned by the NCC) and therefore a Class 9a building.
Class 1 buildings are houses. Typically, they are standalone single dwellings
of a domestic or residential nature.
These buildings can also be horizontally attached to other Class 1 buildings.
When attached they are commonly referred to as duplexes, terrace houses, row houses
and townhouses. In these situations, they must be separated by a wall that has fre-resisting and sound insulation properties.
The Class 1 classifcation includes two sub-classifcations: Class 1a and Class 1b.
A Class 1a building is a single dwelling being a detached house; or one of a group of attached dwellings being a town house,
row house or the like.
A Class 1b building is a boarding house, guest house or hostel that has a ﬂoor area less than 300 m2 and ordinarily has less
than 12 people living in it. It can also be four or more single dwellings located on one allotment which are used for short-term
Class 1 buildings Did you know?
Class 1 buildings cannot be located
above or below any other dwelling
(or any other class of building)
other than a private garage.
Class 2 buildings
Class 2 buildings are apartment buildings. They are typically multi-unit residential
buildings where people live above and below each other. The NCC describes the
space which would be considered the apartment as a sole-occupancy unit (SOU).
Class 2 buildings may also be single storey attached dwellings where there is
a common space below. For example, two dwellings above a common basement
Classifcation is a process for
understanding risk in a building
(or part of a building) according
to its use.
Where it is unclear which classifcation
should apply, the approval authority
has the discretion to decide.
Is it a Class 1b, 2 or 3
Class 3 buildings
Class 3 applies to residential buildings other than Class 1 or Class 2 buildings,
or a Class 4 part of a building. Class 3 buildings are a common place of long term or
transient living for a number of unrelated people. Examples include a boarding house,
guest house, hostel or backpackers (that are larger than the limits for a Class 1b building).
Class 3 buildings could also include dormitory style accommodation, or workers’ quarters for shearers or fruit pickers.
Class 3 buildings may also be “care-type” facilities (such as accommodation buildings for children, the elderly, or people
with a disability) which are not Class 9 buildings.
Class 3 includes residential care
buildings and the residential parts
of hotels, motels, schools, or jails.
Did you know?
Class 6 buildings
Class 6 buildings are typically shops, restaurants and cafés. They are a
place for the sale of retail goods or the supply of services direct to the public.
Some examples are:
• A dining room, bar, shop or kiosk part of a hotel or motel.
• A hairdresser or barber shop.
• A public laundry.
• A market or showroom.
• A funeral parlour.
• A shopping centre.
Is a service station a
Class 6 building?
Yes, as they are intended for the
servicing of cars and the sale
of fuel or other goods.
However, the term “service station”
does not cover buildings where
panel beating, auto electrical,
tyre replacement or the like are
solely carried out. These are
Class 8 buildings.
Class 7 buildings
Class 7 buildings are storage-type buildings. The Class 7 classifcation has two
sub-classifcations: Class 7a and Class 7b.
Class 7a buildings are carparks.
Class 7b buildings are typically warehouses, storage buildings or buildings
for the display of goods (or produce) that is for wholesale.
Did you know?
Reference to wholesale means
“sale to people in the trades or in
the business of ‘on-selling’ goods
and services to another party
(including the public)”.
Class 8 buildings
A factory is the most common way to describe a Class 8
building. It is a building in which a process (or handicraft)
is carried out for trade, sale, or gain.
The building can be used for production, assembling,
altering, repairing, fnishing, packing, or cleaning
of goods or produce. It includes buildings such as
a mechanic’s workshop. It may also be a building
for food processing, such as an abattoir.
A laboratory is also a Class 8 building, even though it
may be small. This is due to the high fre hazard potential.
Are farm buildings Class 7, 8, or 10a?
It depends on the occupancy, use and size. Buildings used
for farming-type purposes are often very diverse
in nature. For example, a shed for parking a single
tractor may be Class 10a, however if multiple tractors
and other farm machinery is parked, the building may be
Class 7a (or even Class 8 if mechanics were employed
to regularly work on the machinery within the building).
The NCC defnes a difference between a farm shed
and a farm building. It also contains specifc Deemed-toSatisfy Provisions for these buildings under Part H3.
Class 9 buildings
Class 9 buildings are buildings of a public nature. The Class 9 classifcation has three
sub-classifcations: Class 9a, Class 9b and Class 9c.
Class 9a buildings are generally hospitals, referred to in the NCC as health-care buildings.
They are buildings in which occupants or patients are undergoing medical treatment and
may need physical assistance to evacuate in the case of an emergency. This includes
a clinic (or day surgery) where the effects of the treatment administered involve patients
becoming unconscious or unable to move. This in turn requires supervised medical care (on the premises) for some time after
treatment has been administered.
Class 9b buildings are assembly buildings in which people may gather for social, theatrical, political, religious or civil purposes.
They include schools, universities, childcare centres, pre-schools, sporting facilities, night clubs, or public transport buildings.
Class 9c buildings are residential care buildings that may contain residents who have various care level needs. They are a place
of residence where 10% or more of persons who reside there need physical assistance in conducting their daily activities and
to evacuate the building during an emergency. An aged care building, where residents are provided with personal care services,
is a Class 9c building.
Did you know?
Laboratories that are part of
health-care buildings are classifed
as Class 9a buildings despite the
general classifcation of laboratories
being Class 8.
Class 10 buildings or structures
Class 10 buildings are non-habitable buildings or structures. Class 10 includes
three sub-classifcations: Class 10a, Class 10b and Class 10c.
Class 10a buildings are non-habitable buildings including sheds, carports,
and private garages.
Class 10b is a structure being a fence, mast, antenna, retaining wall,
swimming pool, or the like.
A Class 10c building is a private bushfre shelter. A private bushfre shelter
is a structure associated with, but not attached to, a Class 1a building.
What is a private garage?
• A garage associated with
a Class 1 building; or
• A single storey of a building
containing not more than
3 vehicle spaces (limited to only
one storey within a building); or
• Any separate single storey
garage associated with another
building that contains no more
than 3 vehicles.
Mixed use buildings How big must a part
of a building be to have
its own classifcation?
Every part of a building must
be separately classifed. However,
where a part has a different
purpose and is not more than
10% of the ﬂoor area of the storey
it is on, subject to some limitations
it may be considered ancillary
to the major use and adopt
For instance, if a single storey
warehouse (Class 7b) has an offce
(normally Class 5) which takes up
only 8% of the ﬂoor area, the whole
building can be classifed as a
Class 7b. However, if the offce
takes up 12% of the ﬂoor area
then the warehouse (Class 7b)
and offce (Class 5) must be
Multiple building classifcations
A building (or a part of a building) may be designed to serve multiple purposes and may have more than one classifcation.
This means that it is permissible for a building to be Class 6/7, or Class 5/6, or whatever is deemed appropriate. This allows
ﬂexibility in how the building might be used. For example, if a building is intended for retail shopping, storage or offce space,
it may be designed as a Class 5/6/7 building.
At the design stage it may not be clear who the fnal tenant will be (or how they will be using their tenancy), so as long as
the design meets the minimum requirements of all the classifcations it could be used for any of the purposes.
As buildings can have mixed uses, they can also have mixed (or multiple) classifcations.
For example, a building may have a basement carpark (Class 7a) with ground
ﬂoor retail space (Class 6) and residential apartments (Class 2) and offces above
Understanding the NCC