Building a garage: kit versus custom, and getting the slab right
Steel kits versus brick, why the slab and approvals are a real slice of the budget, and how to future-proof the build.
A garage is more than a place to park — it's a workshop, storage, a buffer against morning frost on the windscreen, and one of the few additions that reliably adds to a home's value. It's also a real building project, with a slab, footings, approvals and often power to organise.
The choice that sets your budget is construction method: a steel kit garage is the economical route, while a brick garage matched to the house costs roughly half as much again. Knowing what sits between those two ends keeps the quotes readable.
What building a garage involves
A steel kit garage on a new slab is the most economical option — a Colorbond shell, a roller door, erected in a few days. Brick or rendered-block garages built to match the house sit higher, and a fully finished garage with sectional auto doors, lining, lighting and power is the premium end. The slab and footings are a significant slice of the budget in every case, not an afterthought.
Groundwork drives more of the cost than people expect. Cut-and-fill on a sloping block, thicker slabs for heavy use, and stormwater connections all add to the base build. And like any structure, a garage needs council approval, engineering drawings and compliance with boundary setbacks — a good builder maps these out before quoting.
Doors and electrical are the finishing spend. Auto sectional doors, lights and power points add a few thousand over a bare shell, and any wiring — including the auto-door circuit — is a licensed electrician's job.
How the cost works
A single steel kit garage on a new slab sits at the lower end, a double Colorbond garage with slab, auto doors and power connected lands in the low-to-mid tens of thousands, and a custom brick double garage with a full fit-out runs higher again. These are indicative bands; the estimate on this page adjusts for size, construction type and whether you want power.
Size and construction are the two big levers. A double or oversized garage needs proportionally more slab, frame and roofing, and brick or block construction costs meaningfully more than a steel kit. A tip worth heeding: an extra course of wall height or a workshop bay is cheap to add now and expensive to retrofit later, so think about future use before you lock the size.
Choosing the right builder
Whether a garage needs a licensed builder depends on your state and the job's value — structural building work above certain thresholds commonly requires a licence, so check what applies where you live. Electrical work is licensed everywhere: the lighting, power and auto-door circuit all belong to a licensed electrician.
The quote trap to watch is the slab. 'From' prices for kit garages routinely exclude it, so a headline number can be missing thousands of dollars of groundwork. Insist the slab, footings, stormwater and approval paperwork are all itemised, and ask to see a comparable garage the builder has finished — the honest comparison is a full quote against a full quote.
Mistakes to avoid
Garage regrets are usually about a 'from' price that left out the slab, or a size that turned out too tight a year later.
- Comparing a kit 'from' price that excludes the slab against a full quote that includes it
- Skipping the council approval and engineering that a permanent structure needs
- Letting anyone but a licensed electrician wire the lights, power or auto-door circuit
- Building to the minimum size when an extra bay or wall height is cheap to add now
- Forgetting stormwater connection and site works on a sloping block
- Choosing steel purely on price when a rendered garage would suit the house far better
Indicative range only, not a quote — see the full guide for worked scenarios and what moves the price.
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