Building a Granny Flat in NZ (2026): A Smarter, Simpler Way to Add Income and Space

19 Jan 2026

Last reviewed: 25 September 2026

Yes, since 15 January 2026 you can build a detached granny flat of up to 70m² in New Zealand without a building consent, and often without a resource consent too, as long as it meets a set of conditions. You still need a project information memorandum (PIM) from council before work starts, the work has to be done or supervised by licensed building professionals, and it still has to meet the Building Code.

If you’ve been put off by consents, delays or cost, this makes a granny flat a lot more realistic, whether you want rental income, a home for family, or more flexibility on your property. Below I explain what the rules require, what they don’t change, and how people usually pay for the build. For the finance side of your own situation, book a free chat with me.

What is a granny flat?

A granny flat, also called a minor or secondary dwelling, is a small, self-contained, standalone home on the same property as your main house. Most have a bedroom, a bathroom, a kitchen and a living area.

Despite the name, they aren’t only for grandparents. People commonly use them for:

rental income
adult children saving for their first home
elderly parents who want independence close to family
guest space or a home office.

The granny flat rules in NZ, explained simply

The Government changed the rules to make small standalone homes faster and cheaper to build. There are two separate sets of rules, and both took effect on 15 January 2026. The building consent exemption sits under the Building Act and is about how the flat is built. The planning rules sit under the Resource Management Act and are about where it goes on your site. They work independently, so meeting one doesn’t mean you’ve met the other.

1. Building consent exemption (up to 70m²)

You don’t need a building consent if your granny flat meets every one of the conditions, which include that it:

is new, standalone and single-storey, with no mezzanine floor
has an internal floor area of 70m² or less
has a floor level no more than 1 metre above the ground, and a height of no more than 4 metres above the floor
is at least 2 metres from any other residential building and from any legal boundary
uses a light timber or light steel frame, lightweight roof cladding (up to 20kg per square metre) and wall cladding of up to 220kg per square metre
meets the Building Code, including the rules for water supply, plumbing and drainage
is designed and built, or supervised, by licensed building professionals: Licensed Building Practitioners, plus registered plumbers, gasfitters, drainlayers and electricians.

Those figures come from the official granny flats guidance on building.govt.nz. It’s worth reading in full before you design anything, because it also covers building on land with natural hazards.

The paperwork still matters. You need to apply for and receive a PIM from council before any building work starts. Councils don’t inspect exempt work or issue a code compliance certificate, but they do keep the records on your property file. Once the PIM is issued you have two years to finish the build, and within 20 working days of finishing you have to give council the final plans, Records of Work, Certificates of Work, and the electrical and gas certificates. Any development contribution is also due within that 20 working days.

2. Resource consent (planning rules)

Under the National Environmental Standards for Detached Minor Residential Units (NES-DMRU), one granny flat per site can be built without resource consent in residential, rural, mixed-use and Māori purpose zones, as long as it meets the standard’s rules. These cover:

floor area (70m² or less)
building coverage on the site (no more than 50% in a residential zone)
distance from the main house (at least 2 metres)
boundary setbacks, which differ by zone.

Your council can still apply some district plan rules, such as those dealing with natural hazards and water, wastewater and stormwater servicing, and regional plan rules still apply. Check your district plan and talk to your council early.

In short: if your design and your site meet both sets of criteria, you may be able to skip both building consent and resource consent. The changes cut red tape. You’re still responsible for building it properly.

What the rules don’t change

The build must still comply with the Building Code.
Work must still be done or supervised by licensed professionals.
You still need a PIM before you start, and council still needs your records when you finish.
Water, wastewater and power connections must be compliant.
Development contributions or other council fees may still apply.
The exemption only covers new granny flats built after it took effect. If building work had already started before 15 January 2026, if you’re altering or adding to an existing building, or if the flat is already built, it needs a building consent in the usual way.

Why more Kiwis are looking at granny flats

Extra income without buying another property

A granny flat can bring in rent without you saving another deposit, buying a separate investment property or taking on a second full mortgage. Many owners put the rent towards their mortgage. Whether the numbers stack up depends on your area, the build cost and how the lender treats the rent. If you’re weighing a granny flat against a separate rental, my property investment loans page covers the other route.

Flexible living for family

Granny flats suit parents who want to stay independent but nearby, adult children priced out of the market, and families who want to live across generations without being crowded. You get closeness and support, and everyone keeps some privacy.

Better use of land you already own

Rather than upgrading or buying again, you can use spare backyard space and add long-term flexibility to your property. How much value it adds varies. Buyers often see a well-designed granny flat as a plus, but that isn’t guaranteed.

How to finance a granny flat

This is the question I get asked most, and the answer depends on your situation. The common options are:

A top-up on your existing mortgage, using the equity in your home. In many cases this is the simplest route.
Refinancing. If you’re borrowing more anyway, it can be a good time to check whether your current lender is still the best fit. See my refinancing page.
Lending that matches staged build payments, so money is drawn as the builder invoices rather than all upfront.
A separate build loan, refinanced when the flat is finished. Sometimes this is the cleaner structure.
Bank special offers. Some banks run discounted lending for things like energy-efficient improvements. Offers and eligibility change, and they may not cover a new granny flat, so I’ll check what currently applies.

Banks don’t all assess granny flats the same way, especially on how much of the future rent they’ll count and how they value the finished property. Getting advice before you sign with a builder can make a real difference to what you can afford. For a first look at your numbers, try the mortgage calculator or read how much can I borrow.

Example: planning a granny flat under the new rules

This is an illustrative example, not a real client.

Sarah and James own a home in Hamilton with a large, flat backyard. They want a granny flat for James’s mum, with the option of renting it out later. For years, uncertainty about consents and cost kept them putting it off.

Their plan is a 60m² detached, single-storey, self-contained unit, set well back from the boundaries and the main house, and designed to meet the Building Code and the NES-DMRU. If it meets every condition, they may not need building or resource consent, as long as they get a PIM before starting, use licensed tradespeople and file their records with council when it’s finished.

Before talking to builders, they checked the finance. They had usable equity, their bank was open to a mortgage top-up, and the repayments looked manageable. That let them go ahead with designs and pricing without rushing or over-committing.

Frequently asked questions

Do I need consent to build a granny flat in NZ?

Often not, for a new, detached, single-storey granny flat of up to 70m² that meets all the conditions. You still need a PIM before you start, you must use licensed professionals, and the build must comply with the Building Code. If your design or site doesn’t meet the criteria, the normal consent process applies.

How much does a granny flat cost in NZ?

It varies a lot with size, design, site work and location, so I’d rather not quote a typical figure. Get fixed quotes, and allow for connections, site work, the PIM, development contributions and other council fees before you settle on a budget.

Will a bank lend for a granny flat?

Many will, usually as a top-up on your existing mortgage using the equity in your home. Lenders differ on valuation, how rental income is counted and how build payments are drawn, so the structure matters.

Can I rent out a granny flat?

Generally yes, subject to tenancy law and local council rules.

Can I sell a granny flat separately from the main house?

Usually not. A granny flat stays part of the main property unless the land is subdivided.

Want to know if a granny flat works for you?

Before you speak to builders or designers, it helps to know how much you could borrow, whether your equity is usable, what the repayments might look like and how to structure the loan. You can use the quick assessment form below, book a free chat with me, or get in touch here. There’s no obligation.

Sources

Building Performance (MBIE), Granny flats exemption guidance
Building Performance (MBIE), Granny flats building consent exemption becomes law on 15 January 2026
Ministry for the Environment, National Environmental Standards for Detached Minor Residential Units

This article is general information only and is not personalised financial advice. It does not take account of your objectives, financial situation or needs. Building and planning rules, council requirements and lender policies change, so check the current rules with your council and building.govt.nz before you build. All lending is subject to each lender’s own criteria and approval. Details of our services and fees are set out in our Disclosure Statement.

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