Minor dwelling (granny flat)

⚠️ This entry contains figures or rules that change with government policy or RBNZ settings. Check the current position at the source link below before relying on it.

A minor dwelling — commonly called a granny flat, and termed a Detached Minor Residential Unit (DMRU) in planning law or a small standalone dwelling under the Building Act — is a self-contained secondary dwelling on a site with an existing primary house.

What changed on 15 January 2026

Two exemptions came into force together:

• Building consent exemption under Schedule 1A of the Building Act 2004
• Resource consent exemption under the National Environmental Standard for Detached Minor Residential Units 2025, which makes one compliant unit a permitted activity in most residential, rural, mixed-use and Māori purpose zones

A qualifying granny flat can now be built without either consent.

The conditions — all must be met

• Maximum 70m² gross floor area, including any internal garage
• Single storey. A mezzanine counts as a second storey and disqualifies the build
• Detached and freestanding — not attached to the main house
• Lightweight construction — lightweight framing and roof; heavy masonry generally falls outside
• At least 2m setback from boundaries and other buildings
• One per site, ancillary to an existing primary dwelling
• Designed and built or supervised by Licensed Building Practitioners
• Must fully meet the Building Code — the exemption removes the consent, not the standard
• PIM required before starting, and council must be notified on completion

Restricted Building Work rules still apply.

It can be rented

The unit does not have to house a family member. It can be tenanted, which is why this matters to investors — it is one of the fastest routes to adding a second income stream on an existing site.

The traps

There are no council inspections. Oversight shifts from the council to you. If a builder cuts a corner on framing, bracing or weathertightness, nobody catches it before the linings go on. Builder selection matters more than it ever did.

Zoning rules still apply. A build exempt from building consent can still need resource consent if site coverage, height-to-boundary, stormwater or hazard overlay rules are breached. Check both regimes.

Insurance and lending are still settling. Some insurers and lenders are working out how to treat consent-exempt dwellings. Confirm policy wording and lending criteria before you commit.

Breach any single condition and the whole project reverts to the standard consenting process.

Common misunderstanding

"No consent" does not mean "no rules." Full Building Code compliance, LBP involvement, a PIM and completion notification are all still required.

Related terms

Sources

• Building Act 2004, Schedule 1A
• National Environmental Standard for Detached Minor Residential Units 2025
• building.govt.nz — granny flats exemption completion checklist

Last reviewed: 1 August 2026 · Rules are new and guidance is still developing. General information only.

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