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Merbau Decking

Starting From Just $4.95

Merbau decking is a dense, durable hardwood suited to Australian outdoor builds. With natural termite resistance, Class 1 durability, and BAL 29 compliance, it’s built for long-term performance. Greenhill Timbers carries a full range of set and random lengths in sizes from 90x19mm to 140x19mm, with trade-ready supply and expert advice on hand.

SKU: MB.D.140-1-1 Category: Grades: Standard & Better Janka Rating: 8.5
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Product Description

Merbau Timber Decking – Durable, Compliant, and Ready to Go

Merbau has been a mainstay in Australian decking for decades and for good reason. It copes well with our climate, from coastal humidity to intense sun. You’ll often see it used in high-traffic outdoor zones, walkways, and backyard decks that need to last more than just a season.

It’s naturally resistant to rot and insects and doesn’t need chemical treatment to hold up. That’s a bonus for anyone wanting to minimise exposure to treated timber without compromising on longevity.

Merbau also meets the requirements for use in BAL 29-rated bushfire zones, which makes it a safe and compliant choice for builds near bushland. Whether you’re a builder working off a spec plan or a homeowner renovating a back deck, it’s a material you can count on.

Sizes in Stock: 140x19mm, 90x19mm (Random and Set Lengths)

We supply Merbau decking in a full range of options:

  • Merbau Decking 140x19mm Random Lengths
  • Merbau Decking 90x19mm Random Lengths
  • Merbau Decking 140x19mm Set Lengths
  • Merbau Decking 90x19mm Set Lengths

Stock is available for immediate pickup or delivery across Melbourne and beyond.

What to Know Before Installation

Merbau contains high levels of tannins, which is what give it the deep reddish tone early on. But those tannins can leach out when exposed to rain, so it’s worth pre-oiling or sealing the boards, especially on decks near paving or concrete. We recommend sealing all faces, including end grain, before installation.

Spacing matters too. Merbau is dense, but still needs airflow underneath to perform long-term. Allow for expansion and contraction with appropriate board gaps, especially if installing in areas that get direct sun.

Timber Specs & Performance

  • Janka Hardness : ~8.5 kN — one of the hardest decking timbers available
  • Density : 850–900 kg/m³ — very dense, ideal for high-traffic areas
  • Durability Class : Class 1 above ground — rated for 25+ years of service life
  • BAL Rating : Approved for use in BAL 29 bushfire zones
  • Shrinkage Rate : Tangential ~4.5%, Radial ~2.5%
  • Finish : Accepts stains and oils well, or can be left to weather naturally
  • Movement : Low once installed with proper ventilation

Built for Long-Term Use

Merbau is easy to cut and predrill, holds screws and nails firmly, and gives you a clean, even finish. It’s also one of the more stable hardwoods, so once it’s down, it tends to stay put — no major cupping, twisting, or surface checking.

You can maintain the rich colour with oil, or let it fade to a natural grey. Either way, the structural integrity holds up.

Merbau Decking from Greenhill Timbers

We’ve been supplying Merbau to tradies and homeowners for years. Whether you’re after fixed-length packs or random lengths, we’ll help you choose the most efficient setup for your layout. Need it delivered? No problem, we cover all of Melbourne and the surrounds.

Drop in and see our stock, or get in touch for a quote today.

Janka Rating

What Is the Janka Rating?

The Janka rating is a way to measure how hard a timber is, specifically, how much force it takes to push a small steel ball halfway into the wood. The number you get is shown in kilonewtons (kN). A higher Janka score means a harder, more durable timber. Builders and floor installers use it to work out which timbers hold up better in busy areas.

Here’s a rough guide to how some timbers sit on the scale:

  • Brazilian Walnut – around 16.0 kN
  • Spotted Gum – roughly 11.0 kN
  • Tasmanian Oak – about 5.5 kN
  • Radiata Pine – close to 3.0 kN

Keep in mind: these values can vary depending on moisture content and grain direction.

It's One Part of the Decision

Hardness is useful to know, but it’s just one factor. Janka doesn’t tell you how a timber reacts to heat or humidity, how stable it is, or how easy it is to cut and install.

Some of the hardest woods can be difficult to work with. Others, even if softer, might be more stable or forgiving on-site.

At Greenhill Timbers, we look at the whole picture, not just the numbers. All our timbers are structurally graded and covered by a 25-year guarantee. We'll help you pick something that works for your project, not just on paper.

Delivery Options

Melbourne-Wide Delivery

We carefully prepare your order and organise pick-up or delivery that suits your schedule, ensuring your satisfaction when you choose to purchase from us. If you're located in Melbourne and its surrounding areas, you can collect your order from our Thomastown Showroom at 170 Settlement Road. Otherwise, we can facilitate delivery by leveraging our strong partnerships with various sub-contractors to get you the most competitive delivery rate and suitable time frame. For more information, get in touch with us.

Customer Reviews

Why Choose Us

Get Your Timber Packed

Get Your Timber Packed

We pack, wrap and load your products into your vehicle on-site. As a Green Hill customer, you won’t have to pack your timber or lug it into your vehicle after you’ve purchased it.

01
One Stop Shop

One Stop Shop

We are a one-stop shop for all your timber needs. Get dozens of types of wood, both imported and local, and the right cuts for your decking, flooring, cladding and fencing projects.

02
Competitive Pricing

Competitive Pricing

In most cases, we can help you save hundreds or even thousands of dollars on the same materials compared to other timber suppliers.

03
Expert Staff

Expert Staff

Our expert staff will assist you in finding the perfect timber to match your projects based on a relaxed chat to find what you need.

04
Transparent Quotes

Transparent Quotes

We give you the whole picture when we quote you. So you can avoid any nasty surprises down the line.

05

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