Notes for single-storey detached buildings: 2.1-2.5

Sections 2.1-2.5 cover five separate exemptions for single-storey detached buildings. Before you begin your project, there are several things you need to consider.

Sections 2.1-2.5 cover five separate exemptions for single-storey detached buildings.

  • Buildings not exceeding 10 square metres in floor area
  • Single-storey detached buildings exceeding 10, but not exceeding 30 square metres in floor area, constructed of lightweight materials
  • Buildings exceeding 10, but not exceeding 30 square metres in floor area using a kitset or prefabricated building where a manufacturer or supplier has had the design carried out or reviewed by a Chartered Professional Engineer
  • Buildings not exceeding 30 square metres in floor area where a Licensed Building Practitioner is to carry out or supervise design and construction.
  • Unoccupied detached buildings

Before you begin your project, you need to consider the following:

District planning

Always check with your local council to make sure your proposed building work does not have any district or regional planning implications taking consideration of maximum site coverage, yard or setback requirements, daylight access planes or permitted activities. A resource consent may be required and it is important that this is obtained before starting any building work.


Any buildings that include bathroom facilities cannot be built using these exemptions. A building consent is required


The Building Code requires building materials, components and construction methods to be sufficiently durable to ensure the building (without reconstruction or major renovation) satisfies the other functional requirements of the Building Code for the life of the building.

Smoke alarms

You must install smoke alarms if the detached building is going to be used for sleeping. Please refer to Acceptable Solution F7/AS1 for more information on the location and type of smoke alarms to install. It is recommended that any smoke alarm in a sleepout is interconnected with the smoke alarms in the main dwelling.

Compliance Document for New Zealand Building Code Clause F7 Warning Systems [PDF 400KB] which includes Acceptable Solution F7/AS1


You need to consider the Building Code requirements regarding the disposal of stormwater from the roof of your building. You should seek professional guidance and seek approval from your council. All new drains must be laid by an authorised drainlayer.

On-site waste water disposal systems

If the building is intended to be a sleepout in connection with an existing dwelling, and the waste water from the existing dwelling discharges to an on-site waste water disposal system (i.e. a septic tank), you need to check that the existing waste water disposal system has the capacity for the extra persons.

Location of services

You need to confirm the location of any underground services that could affect the location of the build. Check with your local council and an underground services location company to ensure you are not building over any existing below ground services, such as drains, electricity, gas, telecommunications etc


Building close to boundaries

If you are building close to boundaries, you need to consider the Building Code requirements regarding protection from fire, particularly in relation to the external spread of fire to neighbouring property.

Measuring the net floor area

The net floor area in a building is measured to the inside of the enclosing walls or posts/columns.

Note for manufacturers of prefabricated buildings

If you are a supplier or manufacturer of proprietary garden sheds, greenhouses, cabins or sleepouts, we recommend that you make sure anyone buying them is aware of the how the small building is to be used and located in order to be exempt from needing a building consent. If a small building is not used or located as required by the exemption, the purchaser will need to apply for a building consent.

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: