In early 2026, New Zealand's building consent system expanded to allow consent-exempt granny flats under new rules set by the Ministry of Business, Innovation & Employment (MBIE). If you're a builder, carpenter, or project manager working on residential projects, understanding these changes is essential to staying compliant and capitalizing on this new opportunity.
What Changed in 2026?
The granny flat exemption scheme, which began in January 2026, allows homeowners to build small secondary dwellings on their property without council building consent, provided they meet strict national standards.
In April 2026, the government expanded the scheme further, allowing off-site construction of consent-exempt units before a Project Information Memorandum (PIM) is issued. This means tradies can now pre-build compliant granny flats in a workshop or on a staging area, then transport and install them on-site—dramatically speeding up project timelines.
The Key Size and Specification Limits
The rules are simple but strict:
Maximum floor area: 70 square metres (about 750 square feet) - This includes all living, sleeping, kitchen, and bathroom space - Decks and porches under 10 sqm don't count toward the total
Height limits: - Maximum wall height of 6 metres from finished ground level - Maximum ridge height of 8 metres
Single storey only: No multi-level units qualify for the exemption
Must have: - Separate entrance and exit (not shared with main house) - Self-contained bathroom facilities - Kitchen or kitchenette - Outdoor living space (deck or patio)
If your design exceeds any of these measurements, you'll need traditional building consent—which can add 6-12 weeks and $800–$2,000+ in council fees depending on your local authority.
Who Can Build These Units?
Any tradie or building company can construct a consent-exempt granny flat, but the building itself must meet the NZ Building Code in full. The exemption is only from the council consent process, not from building code compliance.
This means: - Foundations must be engineered appropriately for the site - Insulation, ventilation, and waterproofing standards still apply - Electrical work must be signed off by a registered electrician - Plumbing must comply with G12/AS1 standards (updated 1 May 2026 for lead content)
Pro tip: Many tradies use Fastcrew (https://fastcrew.nz) to coordinate subcontractors and track compliance documentation on granny flat projects. Having a clear digital trail of who did what—and when—is invaluable if questions arise later.
The Off-Site Construction Game-Changer
Before April 2026, granny flats had to be built on-site, which meant dealing with site logistics, weather delays, and neighbour disruption.
Now, you can: 1. Build the unit off-site in a workshop or on a staging area 2. Get it to meet all code standards 3. Transport and install it on-site (with crane/truck access)
This creates new business opportunities for tradies who can: - Partner with prefab manufacturers - Set up workshop-based granny flat production - Offer "build now, install later" packages
Cost estimate for a 70-sqm granny flat: - Build cost (off-site): $65,000–$120,000 NZD (depending on finishes) - Installation/connection: $8,000–$15,000 NZD - Total: $73,000–$135,000 NZD for a turnkey unit
With no consent fees and faster timelines, many homeowners are choosing this over traditional renovation costs.
What Tradies Need to Document
Even though council consent isn't required, you'll need to maintain comprehensive documentation to prove compliance:
- Building plans showing dimensions, materials, and compliance with Building Code
- Certificates of Compliance for electrical and plumbing work
- Proof of appropriate site investigation (foundation suitability)
- Materials compliance (insulation R-values, waterproofing specs)
- Site photos at key stages (foundations, framing, completion)
This documentation protects both you and the homeowner if any future issues arise. Keep records for at least 10 years.
Tax and GST Implications
If you're registered for GST, granny flat construction work is not GST-exempt—you'll charge the full 15% GST on your labour and materials unless the homeowner is also GST-registered.
For pricing, use our Job Costing Calculator to ensure you're factoring in all costs (labour, materials, transport, crane hire, etc.).
If the homeowner is paying more than $60,000 for the project and they later decide to rent out the granny flat, they may face tax implications. Recommend they speak with an accountant about rental income disclosure requirements to the IRD.
Common Pitfalls to Avoid
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Assuming the exemption covers everything — It doesn't cover non-compliant materials, poor construction, or code violations. You're still building to full Building Code standards.
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Skipping engineer certification — On challenging sites (steep slopes, poor soil, coastal), get a structural engineer's sign-off even though consent isn't required.
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Undersizing utilities — Granny flats still need proper water, wastewater, and power infrastructure. Don't cut corners on plumbing or electrical work.
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Forgetting about council planning rules — Even without building consent, the granny flat must comply with your local council's district plan rules on setbacks, coverage, and use. Check this before you quote.
Where to Get More Information
- Building Performance (Ministry of Business, Innovation & Employment): https://www.building.govt.nz/building-code-compliance/granny-flats/
- Licensed Building Practitioners (LBP) Board: https://www.lbp.govt.nz/
- Your local council's planning and building team (for district plan compliance)
Ready to Offer Granny Flat Projects?
Consent-exempt granny flats represent a genuine growth opportunity for NZ tradies in 2026 and beyond. Homeowners want faster timelines and lower costs—and these new rules deliver both.
If you're considering adding granny flat specialization to your services, start by building your first 1–2 units, documenting everything meticulously, and building a portfolio. Word-of-mouth referrals in the secondary dwelling market are gold.
Download our free NZ Tradie Templates at tradietools.nz/templates/ to get quote templates, site inspection checklists, and compliance documentation forms specifically designed for granny flat projects.
NZ Tradie Tools provides free calculators, templates and guides for New Zealand tradies. Visit tradietools.nz.