Granny flats can soon be constructed without building consent

In this article we discuss the granny flat exemption to the requirement for building consent in the Building Act 2024, and explain what territorial authorities should do to prepare for their reduced role in issuing PIMs and holding records, as well as what owners need to understand when it comes to the difference between meeting the exemption criteria under the Building Act and those of the draft National Environmental Standards for Granny Flats under the Resource Management Act.

The Building Act has been amended to introduce a new exemption from the requirement for building works to be carried out only if authorised by a building consent. The exemption applies to a ‘non-consented small stand-alone dwelling’ (commonly known as a ‘granny flat’), that meets certain conditions. 

The changes are expected to be in force in early 2026, with the commencement date yet to be set by Order in Council.

The ‘granny flats’ exemption

The Building and Construction (Small Stand-alone Dwellings) Amendment Act 2025 (Amendment Act) was passed on 23 October 2025. Under the amendments it makes, in order for building work (including connections on site) to be exempt from the requirement for building consent it must:

• be stand-alone
• be new (not an addition or alteration to existing building work or an existing building)
• have a floor area that is equal to or less than 70m²
• have a single storey only (no mezzanine floor)
• meet the Building Code requirements (for a detached building)
• meet the other specific requirements in new Schedule 1A that include floor level, maximum height (4m above floor), cladding roof and frame material, location from boundary, specifications for water supply, sanitary plumbing and drainage requirements
• have all building work carried out or supervised by licensed building professionals^[1]
• have a Project Information Memorandum (PIM) issued for the site it will be located on, that has not lapsed
• be on land not subject to natural hazards, or not make adequate provision for natural hazards where the construction of the dwelling is likely to accelerate or worsen that hazard
• not built over the boundary of 2 or more allotments.

The exemption does not apply to tiny-homes on wheels or a moveable base, container homes or imported kitset or flat-pack designs which are not designed, engineered or built to meet the New Zealand Building Code.  

There are also consequential changes to the Building Act to provide for the new exemption. These changes include:

• a specific record keeping requirement on territorial authorities in relation to non-consented small stand alone dwellings
• protection for territorial authorities from civil proceedings for anything done in good faith related to their specific roles in the new regime
• development contributions still apply and will be charged by the territorial authority through the PIM process
• an owner has the option to apply for a building consent even if the building could meet the criteria for the exemption, so an owner might choose to do this rather than relying on the exemption. 

The new process: PIMs and records are required

The exemption creates a new PIM process specific to authorising small stand-alone dwellings. To qualify for the exemption, a PIM must be issued before any building work begins. The PIM will confirm whether the site is subject to natural hazards or whether the proposed work could accelerate or worsen such hazards. There is a 10 working day timeframe to issue this type of PIM. An owner will have two years to complete the build from the PIM issue date.

Where a small stand-alone dwelling is built without a PIM being issued first, it will no longer be exempt work and will require a building consent (or retrospective certificate of acceptance). Compliance with the PIM requirement is key to the operation of the exemption from a compliance perspective, as well as being important to the collection of development contributions for these dwellings for territorial authorities. 

After a small stand-alone dwelling is built, the owner is required to send to the territorial authority within 20 working days after completion of the building, Records of Work, final design plans for building, sanitary plumbing, drain laying and Certificate of Work. There is a corresponding requirement on each registered person and provisional licence holder to provide a record of work on completion. Where an owner fails to provide this information to the territorial authority they commit an infringement offence (albeit the building work remains exempt if it met all the conditions). There is no duty on a territorial authority to request, assess or inquire into any of the information that the owner is required to provide. 

This new process is shown in the diagram below. 

Integration with National Environmental Standards under the RMA

The Government intends to make ‘granny flats’ exempt from the need to obtain resource consent under the Resource Management Act 1991 (RMA). The proposed National Environment Standard (NES) for ‘minor residential units’ was consulted on earlier this year^[2], will contain permitted activity standards that are to be  applied across New Zealand, and is expected to be made by the end of 2025. The Amendment Act and the proposed NES are consistent in several ways. Under both the RMA and the Building Act a dwelling would require resource or building consent if it has greater than 70m² floor area, or is set back less than 2m from buildings and 2m from the boundary. Granny flats to be constructed on land subject to natural hazards must be notified to a territorial authority and where construction is likely to accelerate, worsen or result in a natural hazard on the land or any other property, may only proceed if adequate protective measures are in place.

However, there are several additional requirements in the draft NES as consulted on and the exemption introduced by the Amendment Act. Under the proposed NES (but not under the Amendment Act):

• the ‘granny flat’ must be ancillary to a primary dwelling located on the same site
• there can only be one ‘granny flat’ per site
• maximum site coverage rules must be met
• ‘granny flats’ will only be exempt from consent requirements in certain zones under the RMA (notably they are not exempt in a future urban zone)
• different, larger setback requirements apply in rural zones (10m from boundary and 5m from side and rear boundaries), and
• if resource consent is required by a rule dealing with section 6 matters then the district plan rules can still apply.

While the differences reflect the different purposes of the consenting requirements under the RMA as opposed to the Building Act, the position could cause confusion. Territorial authorities and people seeking to build ‘granny flats’ need to be aware that just because a granny flat is exempt from the requirement for building consent, that does not mean it is exempt from any applicable requirement for resource consent (and visa versa). 

Our comment

The Amendment Act reduces territorial authorities’ traditional role from one involving consenting and inspections, to one that only involves issuing PIMs and holding information. Territorial authorities should review their compliance policies to reflect this change and its implications for enforcement. It is also important to consider how these dwellings may be dealt with retrospectively where there is a failure to meet one of the conditions of the exemption. 

Both the NES and the new Building Act provisions must be complied with. While there are clear similarities (such as the area of the dwelling) there are also differences. It remains to be seen whether the final NES closely resembles the consultation version or not. 

Contact us

To learn more about the Amendment Act, or for assistance navigating the new regime, please contact one of our experts listed below.