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Expandable granny flats in NSW: what to check before you buy

An expandable granny flat is built and fitted out at the factory, travels folded and expands on your block. In NSW it still needs an approval, and the rules depend on whether it is treated as a building or as a manufactured home. Here is what applies in 2026, with the official sources, and why our own units cannot be approved yet as currently specified.

What is an expandable granny flat?

It is a steel-framed unit, finished inside at the factory, that travels compactly folded and expands on site. On ours, the two side sections expand to the full floor plan, with no panels to assemble. Our Yard 37 travels 2.2 m wide and expands to 5.9 × 6.3 m; two of them travel end to end in one 40 ft High Cube shipping container. The Yard 57 expands to 9.0 × 6.3 m and fills a 40 ft High Cube container on its own.

Our units are not converted shipping containers: they travel inside one. They have no wheels either. The crane sets each unit on footings designed by an engineer for your site; a licensed builder then fixes it, expands it and fits the seals and small fittings that travel inside it, and its licensed trades make the connections.

Building or manufactured home: which approval applies in NSW?

In NSW, a granny flat is a secondary dwelling: a self-contained dwelling on the same lot as a principal dwelling. The development can only result in one principal dwelling and one secondary dwelling on the lot, and the lot cannot be subdivided. An expandable granny flat can follow one of three pathways:

• Complying development, as a building: a complying development certificate (CDC) from your council or a registered certifier, when the granny flat meets every standard of Schedule 1 of the State Environmental Planning Policy (Housing) 2021, including a lot of at least 450 m² and, in a residential zone, no more than 60 m² of floor area.
• Development application, as a building: lodged with your council when complying development is not available.
• Manufactured home: council approval to install the home under section 68 of the Local Government Act 1993, with development consent where the local planning rules require it. Both can be sought in the same application.

Which one applies depends on how the home is made and delivered. Under the Local Government Act, a manufactured home is a self-contained dwelling, with at least one kitchen, bathroom, bedroom and living area plus toilet and laundry facilities, made of one or more major sections and not a registrable vehicle. A major section is a finished portion of the home with at least 20 cubic metres of living space and all its major components: frame, walls, roof and ceilings, floors, windows and doors, internal plumbing and wiring, and the kitchen, bathroom and laundry fittings. A flat-pack kit, assembled on site from loose parts, is a building instead (NSW practice note, 1 July 2026).

Your council or certifier decides which pathway applies to your unit and your block, and we take no order and no payment until it is confirmed in writing. Our guide to granny flat rules in NSW details the complying development standards.

Is an expandable granny flat a Class 1a building?

Under the National Construction Code, a building is classified by the purpose for which it is designed, built or adapted to be used. Class 1a covers one or more buildings that together form a single dwelling, such as a detached house; Class 10a is a non-habitable building, such as a garage, carport or shed. Where the classification is unclear, the appropriate authority decides (NCC, Part A6).

So an expandable granny flat approved as a building is a dwelling, and it must meet the NCC for a dwelling. A "Class 1a" label from a seller does not decide this: your certifier does. On the manufactured home pathway, the planning Act's definition of a building excludes a manufactured home, and the council assesses the installation under the Local Government Act and its regulation.

The 2.4 m ceiling rule

For a dwelling, the NCC Housing Provisions set minimum room heights: 2.4 m in a habitable room other than a kitchen, and 2.1 m in a kitchen, bathroom, laundry, corridor or passageway. Where a habitable room other than an attic has a sloping ceiling, 2.4 m is required over at least two-thirds of its floor area (NCC 2022, Housing Provisions 10.3). NSW adopts NCC 2025 on 1 May 2027; until then, NCC 2022 applies.

Ask for the height inside each habitable room, from the finished floor to the ceiling, not the outside height of the unit. Our Yard 37 and Yard 57 as currently specified have 2.26 m inside: under the 2.4 m minimum. The Australian versions we are specifying have 2.4 m ceilings, so they are taller: the height is confirmed in your quote.

Does a granny flat need a laundry?

Yes, on both pathways:

• as a building, the NCC requires a Class 1 building to have clothes washing facilities: at least one washtub, with space in the same room for a washing machine. Facilities detached from the granny flat must be for the exclusive use of its occupants, and a kitchen sink or a washbasin does not count as a washtub (NCC 2022, Housing Provisions 10.4);
• as a manufactured home, the definition itself requires toilet and laundry facilities, on top of a kitchen, bathroom, bedroom and living area.

The NCC also requires a kitchen sink and facilities for the preparation and cooking of food (Housing Provisions 10.4.1).

Our current units have a kitchenette without a cooktop, and a bathroom with shower, basin and toilet, but no laundry. The Australian versions we are specifying add a laundry and an electric cooktop.

Footings, tie-downs and wind classes

On the manufactured home pathway, the regulation requires a design certified by a practising structural engineer as structurally sound, installation to the engineer's specifications and compliance plates on the home. Installation itself means connecting the sections, attaching them to footings, and connecting gas, electricity, telephone, water, sewerage and drainage.

For our units, the factory supplies structural drawings and calculations for wind classes N2 and N3 to AS 4055, and an Australian engineer certifies the footings and tie-down for your site. The licensed NSW builder named in your quote builds them, under its own contract with you. In NSW, building a prefabricated secondary dwelling such as a granny flat needs a building licence: the licence for prefabricated metal-framed additions does not cover it.

Asbestos, electrical approvals and WaterMark

An expandable unit made overseas raises three more questions, at the border and on site:

• Asbestos: importing goods that contain asbestos is prohibited, and Australian Border Force lists components of prefabricated housing and sandwich panels among the goods that may contain it. Ask for test reports from an accredited laboratory, on samples from your shipment.
• Electrical: declared electrical articles must be approved before they are sold in NSW, and overseas approval marks are not accepted.
• Plumbing: a licensed plumber may not install a product listed on the WaterMark Schedule without WaterMark certification, and since 1 May 2026, products under a WaterMark licence can only be made if they are Lead Free WaterMark certified.

Our guide to importing a granny flat from China explains each check and the documents to ask for. The materials of our units, and what we require from every factory, are on our standards and approvals page.

What changes with the Building (Approvals and Practitioners) Act 2026?

NSW passed the Building (Approvals and Practitioners) Act 2026 on 4 August 2026, but most of it has not commenced: the Department and Building Commission NSW will first consult on the regulations that support it. Once the relevant parts commence, it will:

• remove the term "manufactured home" from the Local Government Act and the Environmental Planning and Assessment Act;
• remove the need for an approval under the Local Government Act to install a manufactured home;
• define prefabricated building work, and create a certification pathway for it, aligned with the certification of traditionally constructed buildings.

Until then, the existing approval processes continue to apply (NSW Planning, updated 22 September 2026). Check the current position with your council or certifier before you order.

Why our units cannot be approved yet, and what we are doing

As currently specified, the Yard 37 and the Yard 57 cannot be approved in NSW, whichever pathway applies:

• as a building, the NCC requires 2.4 m in habitable rooms, clothes washing facilities and cooking facilities: the units have 2.26 m, no laundry and no cooktop;
• as a manufactured home, the home must include laundry facilities, which the units do not have.

We are specifying Australian versions with 2.4 m ceilings, a laundry and a cooktop. Nothing is payable to us until that version is confirmed and your council or certifier confirms in writing that it can be approved on your block. Both units stay under the 60 m² limit: the Yard 37 has 35.2 m² of floor area (37.2 m² overall), the Yard 57 about 54.3 m² (56.7 m² overall). What their turnkey prices include is set out in our guide to granny flat costs in Sydney.

Questions to ask any seller before you pay

1. Which approval pathway applies to my block, and has my council or certifier confirmed it in writing?
2. What is the height inside each habitable room, from the finished floor to the ceiling?
3. Where are the laundry facilities: a washtub, with space for a washing machine in the same room?
4. For a manufactured home: which practising structural engineer certifies the design, and will the home carry compliance plates?
5. Which evidence shows that the materials and products meet the NCC: a CodeMark certificate, a Certificate of Accreditation, a certificate from a certification body, a report from an accredited testing laboratory, an engineer's certificate or other documents?
6. Are the asbestos test reports from an accredited laboratory, in English, on samples from my shipment?
7. Do the switches, sockets and switchboards carry approval marks recognised in NSW, and are the plumbing fittings Lead Free WaterMark certified?
8. Who builds the footings, sets the unit in place and connects it: a licensed NSW builder with Home Building Compensation cover?
9. What does the price include: delivery, crane, approval fees, footings, connections, GST and council contributions?

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