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Fire safety considerations when building a sleep-out

There’s no question that a sleep-out is a great addition to any backyard. Usually in the form of a cabin and separate from the main house, a sleep-out is mainly used as hobby room, home office or storage space. It does not contain cooking or kitchen facilities and usually shares facilities with the main dwelling. It is not standalone or self-contained accommodation.

From 31 August 2020, additional building consent exemptions have been added to the Building Act. Building consents are no longer needed for a number of new or expanded types of low-risk building work, such as sleep-outs, sheds, carports, outdoor fireplaces and ground-mounted solar panels.

The net floor area of a single storey, detached building is limited to a maximum of 30 square metres. If you are extending an existing single storey detached building, the maximum total net floor area cannot exceed 30 square metres. It’s important to note that building work that does not require a building consent must still comply with the Building Code and other legislative requirements, such as those under the Resource Management Act 1991, the Electricity Act 1992, and the Health and Safety at Work Act 2015.

Kitchen and bathroom facilities are not included in the exemptions, and these restrictions mean the overall fire risk of a sleep-out is reasonably low. However, the risk understandably increases with additions such as heaters.

The fire safety for the sleep-out needs to comply with Acceptable Solution C/AS1. This means smoke alarms are required in accordance with Acceptable Solution F7/AS1 to provide early warning of a fire. Where foamed plastics or combustible insulating materials form part of a wall or ceiling system, the completed system needs to achieve a Group Number of not more than three to limit the surface spread of flame.

If external walls are less than the height of the building away from the boundary and other buildings, then a building consent is required. If less than 1m from a boundary or 2m from a building on the same property, the wall will need to be fire rated for at least 30 minutes and comply with external surface finishes requirements to limit the ignitability of external walls.

As a sleep-out is a smaller building, people may overlook the fire safety measures required when looking to build, so for more information please refer to MBIE guidance here.

~ Sajeesh Nair