Demystifying New Zealand’s Granny Flat Legislation 2026: More Than Just “Draw Plans and Build”
- James Chong
- Jan 22
- 5 min read
By James Chong | Published on 22 January 2026
From 15 January 2026, a major change in New Zealand’s building laws means that many homeowners will be able to build a granny flat (a small stand-alone dwelling) without going through the traditional building consent process, but it’s far from a free-for-all.
While the new rules simplify parts of the regulatory process, they introduce clear steps and responsibilities for homeowners, designers, and builders, and they are crucial to understand if you want a successful and compliant granny flat project.
What the Legislation Actually Does
Under the Building and Construction (Small Stand-alone Dwellings) Amendment Act:
Homeowners can build a stand-alone, single-storey dwelling up to 70m² without needing a traditional building consent, provided it meets all exemption conditions and is built by qualified professionals.
The exemption operates alongside, but separately from, the National Environmental Standards for Detached Minor Residential Units (NES-DMRU). This means even if you’re exempt from a building consent, you still must consider planning rules and whether a resource consent is required under planning law (more on that below).
This exemption is about reducing red tape, not a shortcut around good design, compliance, or safety.
Step-by-Step: The Process Homeowners Need to Follow
1. Early Due Diligence: Know Your Site & Planning Rules
Before anything else:
Check the local district or city plan. Just because the Building Act allows an exemption does not automatically mean you don’t need a Resource Consent. Planning rules, including setbacks, natural hazards, overlay protections, heritage, earthworks, and infrastructure requirements still apply. You may need a Resource Consent depending on location and site constraints.
Confirm if your site is affected by soil conditions, wind zones, flooding, or other hazards that may trigger additional requirements or void the exemption. These issues must be investigated early; they can’t simply be resolved after design. Good designers will flag these risks before plans progress.
This process goes well beyond engaging someone to simply producing drawings.
2. Engage Qualified Design Professionals Early
Even though you may not need a traditional building consent, you do need:
A Licensed Building Practitioner (LBP Design) or Registered Architect to prepare compliant plans, and
A Certificate of Work (CoW), a formal document from that LBP designer, issued before construction, confirming that the design complies with the Building Code.
This is not optional. Without a Certificate of Work, you cannot rely on the exemption, and lenders or insurers are likely to require it for finance and policy cover.
A Registered Architect brings added value here by not only producing compliant plans but also advising on planning constraints, site issues, and optimal design solutions. It’s not just drafting, it’s professional problem-solving.
3. Apply for a Project Information Memorandum (PIM) Before Construction
Before any physical work starts, the owner must apply to the council for a PIM for non-consented small stand-alone dwellings. A PIM does not approve construction, but it is a mandatory prerequisite under the exemption.
A PIM:
Confirms council has been notified of your intent to use the exemption,
Flags any infrastructure conditions, hazards, or planning issues the exemption may not override, and
May include notices for development contributions or other charges that must be paid either before or after construction.
The preliminary plans (prepared by the designer) are submitted with your PIM application. The council must issue (or return for more information) the PIM within approximately 10 working days once complete.
Construction cannot start until the PIM is issued. This is a legal requirement, and one of the most common stumbling blocks in DIY granny flat projects.
4. Construction Must Be Carried Out or Supervised by Licensed Builders
Even with the exemption:
All restricted building work must be done or supervised by Licensed Building Practitioners (LBPs).
All plumbing, drainage, electrical, and gas work must be done by appropriately licensed tradespeople and certified.
This is a key difference from traditional building consent processes: the compliance obligation is on the professionals involved, not the council inspectors.
5. What Is Restricted Building Work (RBW)?
One of the most misunderstood aspects of the exemption is Restricted Building Work (RBW).
What RBW Means
Restricted Building Work is building work that is critical to the structure or weathertightness of a residential building. Because failures in these areas can have serious safety and durability consequences, the law requires this work to be:
Designed by a Licensed Building Practitioner (LBP – Design) or registered architect, and
Carried out or supervised by an LBP (Building).
Examples of Restricted Building Work
RBW typically includes:
Foundations and subfloor structures
Load-bearing walls and framing
Roofing and cladding systems
Structural elements such as beams and bracing
External waterproofing systems
Even though a building consent may not be required, RBW rules still apply in full.
6. Records of Work and Completion Documentation
Once construction is finished, you must compile and submit a complete set of documents to council within 20 working days of completion.
These include:
Final “as-built” design plans,
Certificate(s) of Work from designers,
Records of Work (RoWs) from each licensed builder who carried out or supervised restricted building work, and
Safety certificates (electrical, gas, etc.).
Failure to submit these records may lead to enforcement, or the exemption being invalidated, requiring costly remedial work or a formal building consent retroactively.
Common Misconceptions and Pitfalls
It’s Not Just “Draw Some Plans & Build”
Many homeowners think the exemption means they just need a basic set of drawings before they start construction. In reality:
Plans must demonstrate compliance with the Building Code and exemption criteria.
Site conditions and planning constraints must be assessed properly.
Design professionals must formally certify their work.
Skimp on these, and you risk non-compliance, enforcement action, or rework.
Resource Consents Still Matter
Even if you qualify for the Building Consent Exemption, you may still need a Resource Consent under planning laws unless your project complies with all NES-DMRU standards and local district plan rules.
Site Hazards Can Override the Exemption
Issues such as unstable soil, flooding hazards, coastal wind exposure, and restrictive overlays can trigger additional requirements, including resource consents or engineered solutions that push the project outside the exemption criteria.
Engage designers and engineers who will check these before you commit to build.
Key Takeaways
1. The exemption simplifies consent — but doesn’t eliminate professional responsibility.
2. You must apply for and receive a PIM before building starts.
3. Design must be certified by licensed professionals (architects/LBP Design).
4. Construction must be done by licensed builders and tradespeople.
5. Final documentation must be submitted to the Council on completion.
6. Resource consent and planning rules still apply.
Conclusion
New Zealand’s granny flat legislation brings welcome reforms, lowering time and cost barriers to build a small dwelling and unlocking flexible housing options for homeowners. But it’s not a loophole to avoid professional input, planning compliance, or safety standards.
Engage quality designers and licensed builders early, follow the PIM and documentation process closely, and treat the project as a professional construction, not just backyard carpentry.
Unveil Architects delivers end-to-end architectural services, including planning guidance, detailed drawing production, design certification, and construction oversight, ensuring full compliance with current building regulations while creating solutions carefully tailored to your site and brief.
Disclaimer: The views expressed in this post are my own and do not represent the opinions of any organization or employer. The content is for general information only and should not be taken as professional advice.
Comments