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What is a prefabricated home?
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| Illustrative stock image — not a depiction of any specific builder's product. | |
| Built as | Flat panels or components, assembled on site |
|---|---|
| Share of Australian prefab market | Panelised and componentised just over half (2025)[1] |
| Versus modular | More design freedom, more on-site finishing |
| National baseline | National Construction Code applies[2] |
| In development | National certification process for off-site construction[3] |
Prefabricated is the umbrella term for any building whose components are manufactured off-site. Every modular home is prefabricated; not every prefabricated home is modular. In Australian usage, "prefab" most often refers to panelised construction — walls, floors and roof elements made flat in a factory, delivered as a stack, and assembled on your block.
Panelised versus volumetric §
The distinction that matters is whether the factory produces flat panels or complete three-dimensional rooms.
| Panelised prefab | Volumetric modular | |
|---|---|---|
| Factory output | Flat wall, floor and roof panels | Complete 3D modules, often fitted out |
| Transport | Efficient — panels stack flat | Bulky — one module per truck load |
| Design limits | Few dimensional constraints | Bounded by road transport dimensions |
| On-site work | Substantial — most finishing happens on site | Minimal — mostly joining and connections |
| Weather exposure | Higher | Lower |
| Crane requirement | Smaller, or none | Significant — a major cost line |
Panelised and componentised systems accounted for just over half of Australia's prefabricated-buildings market in 2025.[1] Despite modular construction receiving more attention, panelised building is the larger share of actual activity.
Why the terminology matters when comparing quotes §
Two builders can both describe themselves as "prefab" while offering quite different products. One might deliver a fully fitted-out module requiring only connection; another might deliver a panel kit requiring a full on-site trade sequence to finish.
Those are different risk profiles and different cost structures, even at a similar headline price. The practical question to ask any builder is: what percentage of the finished home leaves your factory, and what still has to happen on my block?
Kit homes and flat-pack §
At the lighter end of the spectrum sit kit homes — a delivered package of materials and components with assembly generally the buyer's responsibility or arranged separately. These occupy a different position again on the same axis: minimal factory completion, maximum on-site work, usually lowest headline price.
None of these categories is inherently better. They trade factory completion against flexibility and against how much project management the buyer takes on.
Regulation §
All of it must comply with the National Construction Code, which sets the structural, fire, energy-efficiency and accessibility baseline nationally, with state planning instruments applying on top.[2]
Certification of off-site work is an area still developing. The 2025 federal budget included funding to create a national certification process for off-site construction, and in May 2026 a further A$39.3 million was committed to trial an open-source kit-of-parts platform known as System 600, developed with the Building 4.0 CRC.[3] Neither replaces existing state requirements yet, but both signal where the sector is heading.
Practical questions §
- What proportion of the home is completed in the factory?
- Which trades still need to be engaged on site, and by whom?
- Is a crane required, and is it included?[4]
- Who certifies the factory-built portion, and at what stages?
- What documentation is provided at handover?
Cost guidance for both approaches is collected in the modular cost guide.
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References §
- Prefab News Australia / Mordor Intelligence — Australian prefabricated buildings market — panelised and componentised systems accounted for just over half the market in 2025; residential construction about 57% of the market; Sydney about 24% of demand. mordorintelligence.com/industry-reports/australia-prefabricated-buildings-industry
- Granny Flat Guide — Regulations overview — the National Construction Code sets the national baseline for building work, with state planning instruments applying on top. grannyflatguide.com/regulations/
- Built Offsite — 2025 federal budget — A$54 million for prefabrication and modular construction, including funding to create a national certification process for off-site construction; May 2026 — a further A$39.3 million to trial the open-source "System 600" kit-of-parts platform developed with the Building 4.0 CRC. builtoffsite.com.au/news/federal-government-backs-prefabrication-and-modular-construction-with-54-million-boost/
- Built by Modify — 2026 modular cost guide — rates per square metre and the separation between factory-stage and site-stage costs; transport sometimes included only within a set radius. builtbymodify.com.au/blogs/modular-home-cost
Figures are as published by the sources above at their respective dates and are paraphrased summaries, not verbatim reproductions. Verify current pricing and rules directly with builders, lenders and planning authorities.