If you're planning a new deck this year, you've probably narrowed the choice down to two names: composite and Merbau. Both are excellent. Both will give you an outdoor space you'll actually use. But "better value" isn't the same as "cheaper on day one," and that's where most Australian homeowners get caught out.

Value is what you pay across the whole life of the deck, not just the invoice from the supplier. At A Class Building Materials, we supply both to Melbourne homeowners and tradies every day, so let's compare the two honestly, using real 2026 pricing, and work out which one genuinely leaves you better off.

What you'll pay upfront in 2026

Here's where the two are surprisingly close on materials.

Merbau costs roughly $100 to $160 per square metre for the boards themselves. It's a dense Southeast Asian hardwood that's been the default Australian decking timber for decades, and steady supply keeps the price competitive.

Composite (a blend of recycled timber fibres and plastic) runs $100 to $250 per square metre, depending on the brand and whether you choose a capped or uncapped board.

Once you add installation, a finished deck lands at around $250 to $400 per m² for Merbau and $250 to $450 per m² for composite. On a typical 30 m² deck, that's a difference of a few hundred to a couple of thousand dollars at most, with Merbau usually the cheaper starting point.

If the decision ended there, Merbau would win. But it doesn't end there.

The cost most people forget: maintenance

This is the number that changes everything.

Merbau is a natural timber, so it needs oiling to keep its colour and stop it drying out, greying and cracking. Plan on annual oiling (bi-annual at the absolute minimum), which costs somewhere between $300 and $800 a year once you factor in the oil, the prep, and either your weekend or a contractor's time.

Stretch that across a 20 year lifespan and Merbau maintenance quietly adds up to $6,000 to $16,000 on a mid sized deck. That's often more than the deck cost to build in the first place.

Composite asks for none of that. A wash down with soapy water a couple of times a year is the whole job. No sanding, no oiling, no recoating. Over 20 years, the maintenance saving alone typically works out to $5,000 to $14,000 in composite's favour.

So while Merbau wins the upfront round, composite usually wins the total cost of ownership battle, often by a wide margin.

Lifespan and durability

A well maintained Merbau deck lasts around 20 to 25 years. The catch is in those two words. Skip the oiling and that lifespan drops noticeably as the boards weather, split and lift.

Composite is engineered to last 25 to 30 years or more, and most quality brands back that up with a 15 to 30 year warranty. Merbau, being a natural product, rarely comes with any manufacturer warranty at all.

Composite also shrugs off the two things that age a timber deck fastest: it won't rot, and it won't be eaten by termites. In Australian conditions of harsh sun, driving rain and humidity, that consistency counts for a lot.

Where Merbau still wins: the look

Let's be fair to timber, because this is real. Nothing quite matches the warmth of genuine Merbau. That rich reddish brown grain, the natural variation from board to board, the way it feels underfoot. Composite has come a long way, but a natural hardwood still has a character that a manufactured board can only imitate.

If you love living, natural materials and don’t mind the upkeep, Merbau is a beautiful choice. Plenty of homeowners happily oil their deck each spring and consider it part of owning the thing.

Two practical things to know about Merbau

Before you commit to timber, go in with your eyes open on two points.

Tannin bleed. Merbau is loaded with natural tannins, and for the first couple of years those tannins leach out and leave reddish brown stains on anything nearby: concrete paths, pavers, rendered walls and pool coping. It fades after two to three years, but it catches a lot of people by surprise. Composite produces zero tannin bleed.

Splinters. As Merbau ages, it can develop splinters, especially in high traffic spots. If you've got young kids or dogs, or you like being barefoot outside, it's worth weighing. Composite stays splinter free for its entire life.

Installation

Composite installs noticeably faster, often 50 to 70% quicker, thanks to hidden clip fastening systems and boards that are milled to consistent dimensions. Merbau has to be pre-drilled at every fixing point to stop the ends splitting, which is slower and adds labour. For a DIY build, the composite process is more forgiving. For a contractor build, faster install can offset some of composite's higher material cost.

So which is better value in 2026?

Here's the honest verdict.

Choose Merbau if your priority is the lowest upfront cost, you genuinely love natural timber, and you're happy to oil it once a year for the next two decades. It's a warm, proven, budget friendly starting point.

Choose composite if you want the best long term value and the least hassle. You'll pay a little more up front, but you'll save thousands in maintenance, avoid tannin stains and splinters, and get a longer lasting deck with a real warranty behind it.

For most Australian households who want to build once and then just enjoy the space, composite is the better value over the life of the deck. For those chasing the lowest price and the natural timber look, and who don't mind the upkeep, Merbau still earns its place.

Whichever way you lean, the smartest move is to price both for your actual deck size before deciding. If you'd like a materials quote or a hand comparing the two for your project, get in touch with A Class Building Materials. We stock composite and Merbau decking across Australia, and we'll give you the straight numbers, not a sales pitch.