Researchers Unveil Free Plans for Granny Flats to Aid Families

Homeowners in New Zealand can now access free architectural plans for granny flats, thanks to funding from Branz, an independent building research organization. The initiative, spearheaded by researchers at Auckland University, aims to support families seeking additional living space under new legislation effective from January 15, 2026.

The Building and Construction (Small Stand-alone Dwellings) Amendment Act 2025 allows homeowners to construct self-contained dwellings up to 70 square metres without the need for standard building consent. This legislation is expected to facilitate the construction of approximately 13,000 granny flats over the next decade, a significant boost to the housing supply.

Professor Anthony Hōete, leading the project, explains that the open-source plans will cater to various needs, including intergenerational living situations. He emphasizes that these designs could benefit respected elders in the community, transitional housing, or simply provide extra rooms for families. “They could be for kaumātua, it could be transitional housing. Maybe the kids want a couple of extra rooms outside,” he said.

The first phase of the project will involve analyzing 1,000 properties to understand the diversity of living conditions. Following this research, the team will create several designs, complete with detailed drawings and documentation, all available for free download. This partnership with Context Architects aims to deliver aesthetically pleasing and sustainable housing solutions.

The estimated construction cost for these granny flats ranges from $3,500 to $4,000 per square metre, potentially keeping the total below $300,000. Some designs will prioritize universal accessibility, ensuring they accommodate individuals with disabilities as well as seniors.

Hōete expressed enthusiasm for the project, noting, “This is going to give people tangible options where they can be a little bit self-empowered. They can choose from a suite of schemes, go and find a builder and do it.” He highlighted the importance of creating affordable housing options, especially after the economic challenges many have faced in recent years.

This granny flat initiative is one of 22 projects allocated funding as part of a total of $11.5 million from the Building Research Levy, which is collected from building consents exceeding $20,000. Each year, a panel evaluates proposals to identify projects that enhance quality, reduce costs, and improve sustainability in New Zealand’s construction sector.

Other noteworthy funded projects include initiatives focusing on housing solutions for youth, improving energy efficiency in homes, and utilizing AI for equitable design. These projects reflect a commitment to addressing diverse housing needs across the community.

The granny flat legislation underscores a growing recognition of the need for flexible housing solutions in New Zealand. As families seek to adapt to changing living arrangements, this new framework offers a practical pathway for homeowners to expand their living spaces, fostering a sense of community and intergenerational support.