MBIE Determination 2024/013 confirms that changing a residential garage or workshop into sleeping accommodation does not necessarily amount to a “change of use” under the Building Act.
There has traditionally been some uncertainty around whether converting an existing residential garage or workshop into a sleepout automatically amounts to a “change of use” under the Building Act 2004.
MBIE Determination 2024/013, issued in March 2024, provides useful clarification.
In that determination, MBIE concluded that converting an existing residential workshop into a sleepout did not constitute a statutory change of use because both the existing use and the proposed use fell within the same regulatory use category:
SH – Sleeping Single Home.
That distinction can have important implications for homeowners, purchasers and property professionals dealing with garages, workshops, sleepouts and other ancillary residential spaces.
The property contained a detached dwelling and a separate building that had originally been permitted as a workshop in approximately 1987.
The owner proposed carrying out alterations to create habitable accommodation comprising:
There appeared to be no internal cooking facilities, sink or laundry facilities proposed.
The local council considered that the workshop was changing from an IA – Intermittent Low use into an SH – Sleeping Single Home use.
On that basis, Council considered that there was a statutory change of use under the Building Act.
MBIE disagreed.
Under the Building (Specified Systems, Change the Use, and Earthquake-prone Buildings) Regulations 2005, a statutory change of use does not simply occur because a room or building is being used differently in an everyday sense.
The question is whether the building moves from one prescribed regulatory use category to another, where the Building Code requirements for the new use are additional to, or more onerous than, the requirements for the old use.
This is important because changing a building from a garage or workshop into a sleepout does not necessarily mean there has been a legal “change of use”.
Schedule 2 of the Regulations places detached residential dwellings occupied principally by one household within the SH – Sleeping Single Home category.
Importantly, the SH category can also include garages associated with those dwellings where they are used in connection with the occupants of the home.
In Determination 2024/013, MBIE considered the relationship between the workshop and the main dwelling.
MBIE accepted that, in the circumstances of that case, the workshop was an accessory residential structure associated with the dwelling and its occupants and therefore already fell within the SH category.
The proposed sleepout use would also be SH.
Accordingly:
SH → SH = no statutory change of use.
MBIE concluded that:
“The existing building has a use categorisation of SH under the Regulations and therefore, the proposed building work is not a change of use.”
This is an important point.
The fact that historic council plans describe a structure as a garage or workshop does not necessarily mean that using it for sleeping or ancillary living accommodation automatically creates a statutory change of use.
Where a genuine change of use occurs, sections 114 and 115 of the Building Act can become relevant.
Section 115 can require an existing building, following a change of use, to satisfy specified Building Code requirements to a higher standard than may otherwise apply to an ordinary alteration.
In Determination 2024/013, however, MBIE found that there was no change of use.
The proposed work therefore fell to be considered as an alteration to an existing building under section 112 of the Building Act, rather than as a change of use under section 115.
That can be a significant distinction when dealing with older buildings.
Section 112 does not generally require every untouched part of an existing building to be retrospectively brought up to all current new-build standards.
However, the new building work itself must still comply with the Building Code, and the building as altered must meet the requirements imposed by section 112.
No.
This is one of the most important limitations of the determination.
Determination 2024/013 dealt primarily with whether there was a statutory change of use.
It did not establish that all work required to convert a garage or workshop into habitable accommodation is exempt from building consent.
In fact, the owner in the determination was applying for building consent for alterations that included bathrooms, insulation, internal linings, joinery and plumbing work.
There are therefore two separate questions:
1. Is there a statutory change of use?
and
2. Does the physical building work require building consent?
A project can involve no change of use but still require building consent.
Equally, some physical work may be exempt from consent under Schedule 1 of the Building Act, provided the conditions of the relevant exemption are met.
Even where work is exempt from the requirement to obtain building consent, the work must still comply with the Building Code.
This determination may also be relevant when assessing older properties where a garage or workshop has historically been used as ancillary sleeping or living accommodation.
It demonstrates that it should NOT automatically be assumed that:
garage → sleepout = unlawful change of use.
If the building was already an accessory residential structure associated with a detached dwelling and properly fell within the SH category, using that space as ancillary accommodation may remain within SH.
However, this does not automatically establish that all physical alterations carried out to create the accommodation were lawful.
For example, the following types of work may separately require consideration:
The legality of the use and the legality of the building work therefore need to be considered separately.
Another important distinction is between a sleepout or ancillary residential space and a separate household unit.
The proposal considered in Determination 2024/013 did not include internal cooking facilities, an internal sink or laundry facilities.
All parties agreed that the proposed use fell within the SH category.
That does not mean that every self-contained garage conversion will necessarily be treated the same way.
Where a space is capable of operating as a separate household unit, particularly where it contains cooking facilities and can function independently from the main dwelling, different Building Act, Building Code and planning considerations may arise.
The determination should therefore not be interpreted as blanket approval for converting garages into self-contained second dwellings.
This determination is particularly relevant to older residential properties.
It is common for a LIM, historic permit or property file to describe a structure as a:
while the space is currently being used as a sleepout, bedroom, office or ancillary living area.
The fact that the historic description differs from the current use does not automatically mean that an unlawful change of use has occurred.
The correct analysis should instead consider:
For real estate agents and property owners, this determination is useful because it helps separate two issues that are often incorrectly treated as the same thing.
A council file may legitimately describe a building as a garage or workshop, while the building may now be used as a sleepout or ancillary living space without there necessarily having been a statutory change of use.
That does not mean the property should automatically be marketed as a minor dwelling, separate dwelling or Home and Income.
Those descriptions can involve additional legal and planning considerations and should only be used where there is sufficient evidence to support them.
However, an historic council description of “garage” or “workshop” does not, by itself, establish that current ancillary sleeping use is unlawful.
The key lesson from MBIE Determination 2024/013 is relatively straightforward:
A residential garage or workshop associated with a detached dwelling may already fall within the SH – Sleeping Single Home use category.
If the proposed sleepout or ancillary accommodation also falls within SH, there may be no statutory change of use under the Building Act.
That does not remove the need to consider building consent, Building Code compliance, plumbing, drainage, fire safety, planning rules or any other physical alterations carried out to the building.
Each property therefore needs to be assessed on its individual circumstances.
The important point is that the words “garage”, “workshop” and “sleepout” should not automatically be treated as different statutory uses.
The relevant question is the building’s regulatory use category and the nature of the building work that has been undertaken.
This article provides general information only and should not be relied upon as legal, building or planning advice. The circumstances of individual properties vary and appropriate professional advice should be obtained where required.
Reference: MBIE Determination 2024/013, issued March 2024.
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