How much does it cost to build a deck in Australia?

A new deck is one of the best value additions you can make to a home, but the quotes can swing wildly depending on the timber you choose and how high the deck sits. Here is what to expect, and how to read a quote so you know it is fair.

The short answer

Most decks cost between $200 and $600 per square metre supplied and installed. For a typical 20 square metre deck that means roughly $4,000 in treated pine, $6,000 to $9,000 in hardwood, and up to $12,000 in composite. Run your own size and material through the decking cost calculator for a tighter range.

What drives the price

Material is the biggest lever. Treated pine is the budget choice and takes paint or stain well. Hardwoods like merbau and spotted gum cost more but are tougher and look the part. Composite costs the most up front but skips the yearly oiling, so it can even out over a decade.

Height is the next factor. A deck near ground level is quick to frame. Once it goes past about a metre off the ground you are into more posts, bigger bearers and usually a balustrade, which adds materials and labour. Raised and second storey decks often need council approval too, so check the permit checker before you commit.

Material	Per m² installed
Treated pine	$200 to $320
Merbau or hardwood	$300 to $460
Spotted gum	$330 to $520
Composite	$350 to $600

How to keep the cost down

Keep the shape simple, since every corner and step adds labour. Build close to the ground where the design allows, to avoid a balustrade. And get at least three quotes that itemise the substructure, decking and any balustrade separately, so you can compare like with like rather than one lump sum.

These figures are estimates to help you plan and sense check quotes. Site access, materials, finish and your location all change the final price. Always get two or three written quotes.

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