Adding a carport: sizes, approvals and choosing a builder
Kit versus custom, why the slab is a big slice of the budget, and the council check that should happen before anything else.
A carport is the practical middle ground between leaving the car in the weather and building a full garage — cheaper and quicker than a garage, but real shelter that lifts a house's kerb appeal when it's matched properly.
The price runs from a few thousand for a kit over an existing slab to the mid-teens for a custom carport tied into the house. Where yours lands depends on size, roof style and — the part people forget — whether you need a new slab and council approval.
What building a carport involves
The simplest carport is a flat-roof steel kit erected over an existing driveway or slab — posts, beams, a Colorbond roof, done in a day or two. A double gable-roof carport with its own new slab and footings is the common middle option, and a custom carport matched to the house — attached to the roofline, lined, with integrated guttering — is the premium end that reads as part of the home rather than an add-on.
The groundwork is a bigger deal than it looks. If there's no slab, pouring one adds meaningfully to the base kit-plus-install price, and sloping or tight sites add cut-and-fill and access difficulty. Stormwater is the quietly important detail: gutters that drain nowhere cause problems later, so the quote should cover where the water goes.
Attaching a carport to the house adds engineering and finishing work over a freestanding one, because it has to tie cleanly into the existing roofline and flash properly against the wall.
How the cost works
A single flat-roof kit carport over an existing surface sits at the affordable end. A double Colorbond gable carport including a new slab and footings lands in the high single-digit to low-teens thousands, and a custom attached carport with lining and premium finishes runs higher again. These are indicative bands; the estimate on this page adjusts for size, roof style and slab.
Size and slab are the two big levers. A double carport needs nearly twice the roof and structure of a single, and pouring a new slab can add several thousand over building on an existing one. Roof style matters too — a gable or hip roof costs more than a simple flat skillion. Matching the roof colour and pitch to the house costs little extra and lifts resale value.
Choosing the right builder
Whether a carport needs a licensed builder depends on your state and the job's value — structural work above certain thresholds commonly requires a licence, so check what applies where you live rather than assuming. Any electrical work, such as a light or power point, must be done by a licensed electrician regardless.
The check that should come first is council. Most carports need approval, especially near the front boundary where setback and streetscape rules apply, and a good builder raises this before you ask. Ask to see similar carports they've built, and confirm the quote includes footings, the slab if needed, stormwater connection and the approval paperwork — the gaps between those items are where cheap quotes hide.
Mistakes to avoid
Carport regrets are usually about approvals skipped and slabs or stormwater left out of the quote.
- Building without checking council rules — front-boundary carports especially need approval
- Comparing a 'from' price that excludes the slab against a full quote that includes it
- Forgetting stormwater connection and leaving gutters draining onto the ground
- Assuming a licence isn't needed without checking your state's threshold for structural work
- Letting anyone but a licensed electrician wire a light or power point
- Mismatching the roof colour and pitch to the house and losing the resale upside
Indicative range only, not a quote — see the full guide for worked scenarios and what moves the price.
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