🏡 Minor Dwellings: How the New Rules Could Simplify Small Home Builds

By James Chong | Published on 16 October 2025

As housing affordability and density pressures continue to shape New Zealand’s towns and cities, minor dwellings, often called granny flats or secondary dwellings, are emerging as a smart, flexible way to add value and living space to your property. Now, with the Government proposing to ease consent requirements for small standalone homes, New Zealanders could soon find it much easier to build compact, self-contained dwellings without the usual paperwork.

These new national rules are expected to come into force in early 2026, marking one of the most significant updates to small home construction in decades. So, how do these new rules differ from the existing ones, and when will you still need an architect, building consent, or resource consent? Let’s break it down.

A contemporary minor dwelling in the backyard of the main house

🏠 What Is a Minor Dwelling?

A minor dwelling (or secondary residential unit) is a self-contained home that shares a site with a main dwelling and includes its own kitchen, bathroom, and living area. It provides independent living for family members, guests, or tenants and is increasingly popular in both urban and rural areas across New Zealand.

Most councils allow minor dwellings in residential zones, provided they meet local plan standards for size, setbacks, height, and outdoor space.

⚖️ Current Rules in New Zealand

Under existing district plan provisions (which vary between councils):

• ✅ One minor dwelling is usually permitted per site, provided all standards are met.

• 📏 Maximum floor area: typically around 60–65 m² (check local rules).

• 🏠 Must remain secondary to the main dwelling.

• 🚗 Must provide vehicle access and outdoor living space in line with local planning standards.

• 🧱 Building consent is required for all new dwellings.

• 🏛️ Resource consent is triggered if the proposal breaches development standards (height, setbacks, coverage) or if the site is within a special overlay (heritage, flood, coastal, etc.).

  
  

🆕 Proposed Rules – Small Standalone Dwellings (MBIE, 2024)

The Ministry of Business, Innovation and Employment (MBIE) has proposed a new building consent exemption for small standalone dwellings — currently before Parliament and expected to take effect in early 2026.

If approved, this exemption would allow certain new, single-storey, detached dwellings to be built without a building consent, provided they meet strict design and construction conditions.

Modern open-plan design of a minor dwelling

Typical 70 m2 minor dwelling layout with 2-Bedrooms, 1-Bathroom, Living, Dining, Kitchen, and Laundry

1. ✅ Simple, New, and Standalone

• Must be a new, detached, single-storey dwelling.

• Classified as “Housing – detached dwelling” under Clause A1 of the Building Code.

• Intended for a single household or family.

• Must fully comply with all relevant Building Code clauses, including structure, durability, fire safety, moisture, and energy efficiency.

  
  

2. 📏 Building Dimensions and Site Placement

• Maximum net floor area: 70 m² (up from 65 m²).

• Maximum height: 4 m above the floor level.

• Maximum floor level: 1 m above ground.

• Setbacks: At least 2 m from all boundaries and 2 m from other buildings.

Any breach of these limits would trigger the need for building consent.

3. 🧱 Construction Materials

Only lightweight construction systems qualify:

• Roof: Lightweight roofing products.

• Structure: Light timber or light steel framing.

• Cladding: Weight not exceeding 220 kg/m².

Heavier or complex systems will still require consent.

4. 🚿 Amenities and Services

Plumbing and drainage must comply with Acceptable Solutions for:

• Clause E1 (Surface Water)

• Clause G12 (Water Supplies)

Additional requirements include:

• Interconnected smoke alarms.

• Independent power and gas supply points.

• Electric or gas heaters only (no solid-fuel burners).

• Level-entry showers permitted once the relevant LBP licence class is in place.

  
  

5. 👷‍♂️ Licensed Building Practitioners (LBPs) Required

All work must be carried out or supervised by:

• Licensed Building Practitioners (LBPs)

• Licensed plumbers, drainlayers, gasfitters, and electricians

Each must provide:

• Record of Work (RoW)

• Certificate of Work (CoW)

• Electrical or gas safety certificates

This ensures accountability and Building Code compliance.

6. 🏛️ Council Notification Still Required

Even if no building consent is needed, councils must still be notified:

• Before starting work: via a Project Information Memorandum (PIM) request.

• After completion: submit as-built plans for the dwelling and services.

This allows the council to record the new home for rates, contributions, and compliance purposes. However, the council will not review or approve the work under the exemption.

➡️ Note: Building on flood-prone or unstable land may still require consent under Section 71 of the Building Act 2004.

🌿 Site Layout and Amenity Considerations

Every dwelling — including a minor dwelling — must provide adequate daylight, privacy, and outdoor living space. While each council sets its own standards, many follow similar minimums:

Room Type	Minimum Outlook Space	Minimum Outdoor Living Area
Living Room	6 m × 4 m clear space	—
Bedroom	3 m × 3 m clear space	—
Other Habitable Rooms	1 m × 1 m	—
Minor Dwelling Outdoor Space	—	20 m² (min. dimension 3 m)

These ensure comfort and amenity — key factors your architect or designer will assess when planning your site.

📜 When Do You Need Building or Resource Consent?

Scenario	Building Consent	Resource Consent	Explanation
Minor dwelling ≤ 65 m² meeting local plan rules	✅ Required	❌ Not required	Permitted if all standards met, but still needs building consent.
Standalone dwelling ≤ 70 m² meeting MBIE exemption	❌ Exempt	✅ If overlays or local rules breached	May be exempt from building consent but overlays (heritage, flood, coastal) still trigger resource consent.
Site in flood, coastal, or heritage area	✅ Required	✅ Required	Overlays override exemptions; both consents needed.
Exceeds height, setback, or coverage limits	✅ Required	✅ Required	Any breach removes “permitted” status.

🧭 Regional Planning Context

Each district or city council sets its own zoning and development controls under the Resource Management Act 1991 (soon to be replaced by the Spatial Planning and Natural and Built Environment Acts).

In most residential zones, one minor dwelling per site is permitted, but overlays or hazard zones can change what’s allowed. Even with new national exemptions, resource consent may still be required where local plan rules apply.

🧩 Why You Still Need an Architect or Design LBP

Even with simplified rules, professional input remains crucial for:

• 📐 Site-specific layouts that meet both Building Code and local plan standards.

• 🔥 Managing fire separation and boundary setbacks.

• 💧 Designing drainage, water supply, and stormwater systems.

• 🧱 Coordinating with engineers and contractors.

• 🏗️ Preparing council notifications and as-built documentation.

• 🌊 Assessing natural hazards and compliance risks.

An architect ensures your small home is compliant, efficient, and adds lasting value to your property.

A minor dwelling as an on-site home for the family, a retreat, or a rentable investment unit.

🏁 Summary

• ✅ Minor dwellings generally permitted nationwide up to around 65 m², subject to local plan rules.

• 🏗️ Proposed MBIE exemption allows standalone dwellings up to 70 m² without building consent, if fully compliant.

• 📏 Must maintain 2 m setbacks and 4 m height limits.

• 🧱 Must use lightweight construction and be built under LBP supervision.

• 🏛️ Council notification still required.

• ⚖️ Resource consent still applies where overlays or local rules are breached.

• 👷 Architectural design remains key to quality and compliance.

• 📅 Expected to take effect in early 2026.

  
  

💡 Final Thoughts

The proposed MBIE exemption represents a major step towards simplifying small home construction across New Zealand, expected to roll out in early 2026.It opens new opportunities for homeowners to create affordable, independent living spaces — whether for family, guests, or rental income.

However, regulatory and design complexities remain. Working with an architect experienced in local planning and the Building Code ensures your project takes full advantage of these new pathways while maintaining safety, comfort, and long-term value.

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.