Granny Flat Exemption NZ: Can It Be a Shipping Container?

Since 15 January 2026, a small standalone dwelling of up to 70 m² can be built in New Zealand without a building consent, provided it meets the conditions in Schedule 1A of the Building Act. The change came from the Building and Construction (Small Stand-alone Dwellings) Amendment Act 2025, and MBIE’s granny flats guidance (version 2) reflects amendments to Schedule 1A that took effect on 8 October 2026. On the planning side, a national environmental standard now permits these units in most zones.

Many people ask whether a converted shipping container can use the exemption. MBIE’s guidance does not mention shipping containers, and the exemption is written around lightweight framing. Our view is that you should plan a container granny flat as a consented build unless your council confirms in writing, through the project information memorandum (PIM), that your design is likely to meet Schedule 1A. This guide explains the conditions, the process and the reasons for that caution.

What the exemption requires

What changed on 8 October 2026

Version 2 of the MBIE guidance covers amendments to Schedule 1A from 8 October 2026. They allow certified composite structural building products as an alternative to light timber or light steel framing, and clarify the rules on connections to network utility services and on-site water, wastewater and stormwater systems. The basic limits on size, distance, height and professionals did not change.

The PIM process

1. Apply to the council for a PIM on Form 2AA before any work starts.
2. The council issues Forms 2AAB and 2AAC and says whether the work is “likely”, “likely not” or “unclear” to meet the exemption.
3. A development contribution notice (Form 3A) comes with the PIM. Simpli says contributions are payable within 20 days of completion; Central Otago says as notified.
4. Build within 2 years of the PIM being issued.
5. Lodge completion documents within 2 years of the PIM or 20 working days of completion, whichever comes first: as-built plans, the LBP certificate of design work, records of building work, plumbing and drainlaying records, the electrical safety certificate and any gas certificates. They go on the property file and the LIM.

MBIE does not set a fee. Councils charge for the PIM, and development contributions vary by council.

The planning side: NES-DMRU

The National Environmental Standards for Detached Minor Residential Units took effect on 15 January 2026. A unit of up to 70 m² is a permitted activity in residential, rural, mixed use and Māori purpose zones if it meets the standards. A September 2026 amendment says setbacks are measured from the exterior face of the external wall. The standards do not care what the unit is built from, so they can apply to a consented container unit too. Western Bay of Plenty District Council lists these standards:

Why a container conversion probably needs full consent

• The structure condition names light timber framing, light steel framing or a certified composite product. A shipping container is a structural shell of corrugated weathering steel, with a tare of about 2.2 tonnes for a 20ft unit. It does not obviously fit any of those categories.
• MBIE’s designers’ guide does not mention shipping containers. It refers to factory-built units only in the PIM context, as a dwelling “constructed in a factory and then transported to the final site”.
• Cutting windows and doors into a container calls for engineered steel framing, which sits uneasily with the “simple design” condition.
• If the council’s PIM says “likely not” or “unclear” and you build anyway, you carry the risk of a notice to fix.

This is our reading of the rules, not a ruling by MBIE or a council. A design professional may present a container-based design to the council, and the PIM answer is what counts. If the answer is not “likely”, apply for a building consent: our guide to container homes in NZ covers that route, and our consent guide explains the smaller Schedule 1 exemptions.

Workable alternatives

• Build the granny flat in light timber or light steel framing under the exemption, and use a container next to it for storage. A container simply placed for storage is not building work; see containers for home storage.
• For a bedroom without a kitchen or bathroom, look at a container sleepout, which follows different rules.
• For a full container dwelling, follow the building consent route with an LBP designer and engineer. Our tiny homes and off-grid page covers shell choice and services.

Steps before you buy a container

1. Read the MBIE guidance and your council’s granny flat page.
2. Check your zone against the NES-DMRU standards and any overlays.
3. Engage an LBP designer and ask for a PIM before you buy shells.
4. Once the route is clear, request quotes for the containers with the size, grade and delivery address.