The Reform
Building and Construction Minister Chris Penk and Housing Minister Chris Bishop have confirmed that homeowners will be able to build granny flats up to 70 square metres without needing building or resource consents. The 70m² limit — expanded from the initially proposed 60m² following public submissions — significantly widens the functional potential of consent-free minor dwellings. At 60 square metres, most designs accommodate a single bedroom; at 70 square metres, a two-bedroom layout becomes viable, making the units more suitable for families, elderly relatives, or young adults seeking independent accommodation within a family property.
Penk acknowledged the public’s response directly: “It was the public submissions asking, ‘Why not a bit bigger?'” His reasoning for accepting the extension: “Larger footprints don’t present greater building risks.”
What the Exemption Requires
The consent-free status is conditional, not unconditional. Under the proposed Building Act amendment — expected to be introduced to Parliament by mid-2025 — granny flats must meet four criteria:
- Simple design: the exemption applies to straightforward single-storey structures, not complex multi-storey or architecturally unusual designs
- Building Code compliance: the exemption removes the consent process, not the compliance obligation. The dwelling must meet all applicable Building Code requirements.
- Authorised professionals: work must be carried out by qualified builders and other licensed tradespeople, not unlicensed owner-builders
- Council registration: the structure must be registered with the local council before and after construction
The exemption applies only to new builds that meet the final specifications; existing or currently underway projects are not covered.
The Resource Consent Layer
Alongside the Building Act amendment, a National Environmental Standard (NES) under the Resource Management Act will override local council district plan rules, permitting granny flats in both rural and residential zones without resource consent. This is a critical complement to the Building Act change — without it, a property owner in a zone with strict density controls could satisfy the building consent exemption but still require resource consent under their local district plan. The NES removes that layer for structures within the exemption parameters.
Infrastructure charges through the existing Project Information Memorandum (PIM) process remain applicable. MBIE estimates the reforms could enable approximately 13,000 additional granny flats over the next decade. For builders specialising in residential additions and minor dwellings, the reform creates a significant new market segment where streamlined regulatory requirements and clear liability frameworks — the Building Code remains the standard — provide a workable environment for efficient delivery.
