Some Assembly Required: What Imported Modular Buildings Don’t Bring With Them
Modular is having its moment. In March 2025 the Federal Government announced a $54 million package for prefabricated and modular housing, including $4.7 million toward a voluntary national certification process for offsite construction. In May 2026 New South Wales introduced the Building (Approvals and Practitioners) Bill 2026, which would recognise prefabricated buildings in law for the first time in any Australian jurisdiction. The Bill is still before Parliament. The momentum is real, and for the right project modular is a genuinely good answer.
What has not caught up is the buyer’s side of the transaction. If you are weighing an overseas modular supply contract, there is one idea worth carrying into every conversation: engineering compliance does not travel with the module. It is granted against a specific site, in a specific jurisdiction, under a specific edition of the National Construction Code. A beautifully made module can still be non-compliant the moment it lands on your block, and no amount of admiring the factory will change that.
A building is not a product
It also helps to be honest about how young this market is. The figure most often quoted is that prefabrication represents less than 5% of total Australian construction. It appears in the Productivity Commission’s February 2025 paper Housing construction productivity: Can we fix it?, which describes it as a “best estimate” attributed to industry body prefabAUS rather than an official measurement. Nobody is hiding anything; nobody has actually counted. In a sector that small and that new, buyer protections are still forming, and the burden of proving compliance sits with whoever is paying for the building. That is usually you.
What the code actually asks for
The NCC does not ask whether a product is good. It asks for evidence that it is suitable for its intended use. NCC 2022 Volume One Part A5 sets this out: A5G1 requires materials and products to be fit for purpose, A5G2 requires evidence proportionate to the risk and specifies what that evidence must contain, and A5G3 lists the acceptable forms, including a CodeMark Certificate of Conformity, a report from an accredited testing laboratory, or a certificate from a professional engineer setting out the basis on which it is given.
This is where a lot of overseas documentation quietly fails. An ISO 9001 certificate shows that a factory has a quality management system and manufactures consistently. It says nothing about wind resistance, seismic capacity, footing adequacy or testing to Australian Standards. Consistency and conformity are different claims, and only one of them is what your building surveyor needs. A factory can be immaculately consistent at producing something that does not comply.
Five questions worth asking before the deposit
What design basis was this module engineered to?
AS/NZS 1170.2:2021 divides Australia into wind regions A0 through A5, B1, B2, C and D. For housing within its geometric limits, AS 4055:2021 then converts the region into a site wind class once terrain, shielding and topography are accounted for, ranging from N1 at 34 m/s ultimate to N6 and C4 at 86 m/s. Two identical modules on two sites in the same region can carry very different design loads. Ask for the wind region, the terrain category and the resulting site class, not a warm assurance that the building is “engineered for Australian conditions.”
Does the seismic design address non-structural components?
AS 1170.4:2024 superseded the 2007 edition in June 2024, and its Section 8 covers non-structural elements including ceilings, partitions and mechanical and electrical services. In volumetric construction the inter-module connections and services crossings are exactly where this bites. Confirm the Importance Level too, which in Australia is assigned by the NCC in Volume One Part B1, not by the standard itself.
Can the materials be traced?
Cold-formed steel framing is designed to AS/NZS 4600:2018 and hot-rolled steel to AS 4100:2020, welding follows the AS/NZS 1554 series, and fastenings in concrete fall under AS 5216:2021. Mill certificates, weld procedure qualifications and test reports are the evidence. A steel grade with comparable nominal strength but no traceable test data is not the same thing as a compliant one, however reasonable it sounds in an email.
Who is designing the footings, and against what soil data?
This is almost never the module supplier’s scope, and it is the gap people fall into most often. Residential slabs and footings sit under AS 2870-2011, which classifies sites from A through to P, and piled foundations under AS 2159-2009. Uplift, overturning and tie-down continuity are site-specific by definition. Your site does not care what the last one was classified as.
Has the design been checked for transport as well as for its permanent condition?
Lifting loads, road and sea accelerations, and the in-service state are three different load cases. A module can satisfy one and fail another, and the ocean is not a gentle reviewer.
Who signs, and in which state
The certifying instrument differs by jurisdiction, and it is worth confirming early that your engineer can actually issue the one you need. In Victoria, a building surveyor may rely on a certificate of compliance under section 238 of the Building Act 1993, with Regulation 126 of the Building Regulations 2018 prescribing the approved form. In Queensland, Form 15, the compliance certificate for building design or specification, is an approved form under section 10 of the Building Act 1975 and sections 73 and 77 of the Building Regulation 2021, signed by a competent person appointed by the building certifier. In South Australia, Regulation 61 of the Planning, Development and Infrastructure (General) Regulations 2017 provides for a certificate of an independent technical expert, and the independence test has teeth: no financial interest, no prior involvement in the development. In New South Wales, registered design practitioners issue design compliance declarations under the Design and Building Practitioners Act 2020, now covering class 2, 3 and 9c buildings.
There is also a timing trap for anything ordered now and installed later. NCC 2025 was published in February 2026 and adopted in Victoria from 1 May 2026, while New South Wales and Queensland have deferred adoption to 1 May 2027. A national supply contract can quietly straddle two editions of the code.
The regulator is catching up, slowly
The scaffolding is going up. The ABCB published its Prefabricated, modular and offsite construction handbook in November 2024, Standards Australia released the free handbook SA HB 268 on prefabricated building terminology in May 2026, and the ABCB’s proposed National Voluntary Certification Scheme for offsite manufacturers is out for consultation until 15 September 2026. That scheme is not expected to reach manufacturers until around mid-2028.
Until then, every imported modular project is certified one at a time, on its own evidence. There is no published Australian data on what it costs to rectify a non-compliant imported module, and I would be wary of anyone who quotes you a figure. What I would say from practice is that the work is the same either way: a gap analysis against Australian Standards, and a documented design basis for the site. The only variable is whether it happens while the contract can still be changed, or after fabrication, which is a polite way of describing a much more expensive conversation.
How Solaris Realty can help
Compliance works best as a design input rather than a final hurdle, which is the same argument I made about the NCC generally. With imported modular it is simply louder, because the decisions are made in a factory on the other side of an ocean and are very difficult to unmake afterwards. We help clients test an overseas supply proposition while it is still a feasibility rather than a purchase order: what the module was actually engineered to, what evidence exists, what your site demands, and who will certify it. If modular is part of the answer on a site you are assessing, get in touch. We would rather find the gap now than meet it at the wharf.
This article is general information about compliance pathways for prefabricated construction, not advice on a specific project or supply contract. Always confirm requirements with your building surveyor, structural engineer or the relevant authority.