Granny Flats

As of 15 January 2026, New Zealand homeowners can build a standalone, single-storey granny flat up to 70m² without needing a building consent, provided they meet all exemption conditions under the new Building and Construction (Small Stand-alone Dwellings) Amendment Act 2025.

🏡 Key Features of the Granny Flat Exemption

  • Size & Structure Limits:

    • Maximum floor area: 70 square metres.

    • Maximum building height: 4 metres above floor level.

    • Maximum floor level: 1 metre above ground.

    • Must be single-storey, standalone, and self-contained.

  • Location & Site Requirements:

    • Must be 2 metres or more from other residential buildings and legal boundaries.

    • Cannot be built across property boundaries.

    • Site must be free from unmitigated natural hazards.

    • Must comply with local planning rules and zoning.

  • Design & Construction:

    • Only Licensed Building Practitioners (LBPs), registered architects, or Chartered Professional Engineers (CPEng) can design and build.

    • All work must comply with the Building Code—no waivers or modifications allowed.

    • Specific construction materials are required (checklists available from councils).

  • Documentation & Council Notification:

    • You must apply for a Project Information Memorandum (PIM) before starting.

    • No building consent is required, but councils will store records and issue a PIM.

    • Upon completion, submit all documentation (plans, certificates of work, records of work) to council within 20 working days.

  • Timeframe:

    • Build must be completed within 2 years of PIM issue date (extensions available).

⚠️ Important Considerations

  • Planning Rules Still Apply: Even if exempt from building consent, you must meet district plan rules—e.g., setbacks, height-to-boundary, site coverage.

  • Insurance & Finance: Lenders and insurers may require proof of compliance. Engage early to avoid delays.

  • Quality Assurance: Councils won’t inspect exempt builds, so consider hiring third-party QA checks during construction.

Granny Flat Regulations New Zealand

What can Redco do for you?

Redco Consulting Structural Engineers offer homeowners and builders comprehensive support for granny flat projects in New Zealand, including structural design, siteworks engineering, seismic assessments, and compliance documentation—all tailored to meet the 2026 exemption rules.

🛠️ Services Redco Can Provide for Granny Flats

1. Structural Design & Engineering

  • Custom structural design for standalone, single-storey dwellings up to 70m².

  • Expertise in timber, steel, concrete, AAC (Autoclaved Aerated Concrete), and insulated sandwich panels.

  • Designs that meet Building Code requirements—essential for exempt builds.

2. Siteworks & Civil Engineering

  • Foundation design, retaining walls, drainage, and roading.

  • Site-specific solutions to address natural hazards, slope stability, and access.

3. Seismic Assessments

  • Evaluate existing structures or sites for earthquake resilience.

  • Ensure granny flats are safe and compliant with NZ seismic standards.

4. Documentation & Compliance Support

  • Prepare and certify plans and specifications for Project Information Memorandum (PIM) applications.

  • Provide Certificates of Design Work (CoDW) for restricted building work.

  • Assist with council submissions and record-keeping to meet exemption conditions.

5. Material & Construction Advice

  • Recommend suitable materials for cost-effective, code-compliant builds.

  • Support builders with construction sequencing, QA checks, and documentation updates.

👷 Who We Work With

  • Homeowners: From concept to completion, Redco helps ensure granny flats are safe, legal, and future-proofed.

  • Builders & Developers: Redco provides engineered plans, site solutions, and compliance documentation to streamline builds.

  • Architects & Designers: Collaborate to integrate structural integrity with design vision.

⚠️ Why It Matters for Granny Flats

Under the 2026 exemption, granny flats:

  • Must be designed and built by licensed professionals.

  • Require full Building Code compliance—no shortcuts.

  • Need clear documentation for council records, even without a building consent.

Redco’s experience with modular, relocatable, and light steel framing makes them especially suited to efficient granny flat builds

🏡 Granny Flat Design Brief – NZ 2026

Partnering with Redco Consulting Structural Engineers

✅ Project Scope

  • Type: Standalone, single-storey granny flat

  • Size: Up to 70m²

  • Purpose: Secondary dwelling for family, rental, or future flexibility

  • Consent Status: Exempt from building consent under 2026 regulations (PIM required)

 

🧰 Redco’s Role in Your Build

 

🧱 Builder Checklist

📎 Tips for Success

  • Start with Redco early to avoid delays and ensure compliance.

  • Use their expertise in modular and light steel framing for fast, cost-effective builds.

  • Keep records of all plans, certificates, and QA checks—councils require them post-build.