G‑Flat

Not just for grannies

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Small dwellings. Big possibilities.

What is
a G‑Flat?

Commonly known as ‘granny flats’, G‑Flats are small, single‑storey, standalone dwellings.

Not just for nana, a G‑Flat supports a wide range of living needs, from ageing in place and intergenerational living to housing young adults or creating rental income.

70 m² enabled without building or resource consent under 2026 amendments to the Building Act.

Blueprint for success

Why
design
matters?

Good design is the blueprint for success, ensuring:

  • code compliance
  • scalable, repeatable design
  • usable, liveable spaces
  • cultural and social responsiveness
  • cost predictability
  • confidence for policymakers, lenders, and investors

Poor design leads to fragmented delivery, higher costs, and homes that don’t meet long‑term needs.

Open-source design toolkit

This
project
delivers:

A suite of free, downloadable, G‑Flat designs that:

01 Meet needs

Designed around homeowner and occupant needs.

02 Comply

Developed to comply with the Building Code.

03 Build confidence

Can be priced, procured and built with confidence.

Research into repeatable design

How we’re
doing this:

01

Responsive Design

Surveying homeowners and occupants to understand real needs.

02

Designing for Site

Using national GIS data to identify where G‑Flats can be built and what sizes fit typical sites.

03

Designing for Manufacture

Creating brand‑neutral, builder‑friendly designs that minimise waste, cost, and complexity.

04

Designing for Affordability

Using repeatable details and standardised options to support predictable pricing, with potential for modular, prefab, or kitset solutions.

05

Designing for Finance

Exploring how G‑Flats can meet the requirements of valuers, lenders, and insurers, and investigating equity‑based and innovative repayment models.

Building Research Levy

Who’s
funding
this?

This research is funded by BRANZ through the Building Research Levy.

Hosted by the University of Auckland Waipapa Taumata Rau and led by Ngārchitecture.

BRANZ
Ngārchitecture
Waipapa Taumata Rau, University of Auckland

Collaboration network

Our
partners:

NZCB
UDINZ
ADNZ
Te Kāhui Whaihanga New Zealand Institute of Architects

Start a conversation

Contact
us:

info@g-flat.nz

We would love to hear from you about what you wish to build and why you wish to build a G‑Flat…

Guidance and tools

Resources:

Granny flats exemption

Click for the NZ government guidance, including fact sheets, forms and checklists.

Media coverage

Press: