Composite vs Spotted Gum Decking: The Australian Comparison

Spotted gum is Australia’s premium native hardwood. Composite is the modern alternative. Here’s how they compare on cost, maintenance, durability, and appearance in 2026.

Spotted gum has earned its reputation as one of the finest decking timbers available in Australia. It’s locally grown, exceptionally hard, naturally beautiful, and performs well in our climate. For decades, it’s been the benchmark that other decking materials are measured against.

But spotted gum comes at a premium — both upfront and in the years of maintenance that follow. As composite decking technology has advanced, more homeowners are asking whether modern engineered boards can genuinely match what spotted gum delivers, without the price tag and the upkeep.

This guide compares the two materials across every factor that matters — honestly, and with real Australian pricing.

What Is Composite Decking? Complete Guide →

Quick Comparison: Composite vs Spotted Gum

Figures are indicative only and vary by product selection, design complexity, site conditions, and location.

What Is Spotted Gum Decking?

Spotted gum (Corymbia maculata) is a native Australian hardwood prized for its exceptional durability, distinctive appearance, and versatility. It’s grown commercially across the eastern seaboard — primarily in New South Wales and Queensland — and has become one of the most sought-after decking timbers in the country.

What makes spotted gum stand out is its combination of hardness and beauty. With a Janka hardness rating of 11.0 kN, it’s one of the hardest commercially available decking timbers in Australia — significantly harder than merbau (8.5 kN) and most imported hardwoods. This hardness translates to excellent dent and scratch resistance underfoot.

Spotted gum’s appearance is distinctive: a warm palette ranging from pale honey and light brown through to rich chocolate tones, with characteristic darker flecks and a wavy, interlocked grain that gives each board a unique character. When freshly oiled, spotted gum is widely considered the most attractive decking timber available in Australia.

It’s classified as Durability Class 1 (above ground) — the highest rating — with natural resistance to rot, decay, and termites. This is a genuine premium product, and its price reflects that.

Spotted Gum vs Merbau Comparison →

Cost Comparison: The Premium Difference

Upfront Costs

Spotted gum is the most expensive common decking timber in Australia. Kiln-dried spotted gum decking boards typically cost $140–$250 per square metre — comparable to mid-range and premium composite at $100–$250 per square metre. However, spotted gum installation costs more due to the timber’s extreme hardness.

Spotted gum’s hardness (11.0 kN Janka) makes it physically demanding to work with. Pre-drilling is essential for every fastener — even quality drill bits wear quickly. Blades dull faster, cutting takes longer, and installation labour runs 30–50% higher than softer timbers and significantly more than composite. Total installed cost for spotted gum typically lands between $350 and $550 per square metre, compared to $250–$450 for composite.

Long-Term Costs: Where the Gap Widens

Like all natural timber, spotted gum requires regular oiling to maintain its colour and protect the surface. Because spotted gum is a premium product, owners tend to use premium decking oils — and the deck’s appearance motivates them to stay on top of maintenance. Annual maintenance for a 30m² spotted gum deck typically costs $400–$1,000.

Over 20 years, the total cost gap between composite and spotted gum is substantial. A spotted gum deck that costs more upfront also costs significantly more to maintain — making the lifetime cost difference the largest of any timber-to-composite comparison.

Full Composite Decking Cost Guide →

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Durability: Both Excel, Differently

Spotted Gum Durability

Spotted gum’s durability credentials are genuinely impressive. As a Durability Class 1 hardwood, it offers the highest natural resistance to rot and decay of any commonly used Australian decking timber. Its extreme hardness provides excellent resistance to dents, scratches, and heavy foot traffic. Spotted gum also has strong natural termite resistance, though it’s not completely immune.

The caveat is that spotted gum’s durability is conditional on proper maintenance. Without regular oiling, the timber’s surface becomes vulnerable to moisture penetration, which leads to surface checking (small cracks along the grain), cupping, and eventually structural degradation. Spotted gum is also prone to significant movement — its interlocked grain means boards can twist and cup more aggressively than some other hardwoods if moisture levels fluctuate.

In coastal environments, spotted gum performs well above ground but still requires consistent maintenance to manage salt and moisture exposure. In subtropical climates, mould growth on the timber surface can be an ongoing cleaning challenge.

Composite Decking Durability

Composite decking takes a different approach to durability. Rather than relying on the natural properties of a biological material, composite boards are engineered to resist every form of deterioration: moisture, UV, mould, mildew, insects, and physical wear. Premium capped composite is highly resistant to rot, warping, cracking, cupping, splitting, and splintering when installed correctly under Australian conditions.

Where composite particularly outperforms spotted gum is in consistency. Composite boards perform identically whether they’re maintained meticulously or barely touched — because they don’t need maintenance to stay durable. A neglected composite deck after 15 years looks and performs dramatically better than a neglected spotted gum deck after the same period.

Spotted gum does have the edge in raw hardness and scratch resistance underfoot. Heavy dropped objects or dragged furniture are more likely to leave marks on composite than on spotted gum. For extremely high-traffic commercial applications, this difference can matter.

Maintenance: The Defining Difference

Maintaining Spotted Gum

Spotted gum owners face a maintenance commitment that goes beyond most other timbers. The typical annual routine involves cleaning the deck thoroughly, lightly sanding any raised grain or rough patches, and applying 1–2 coats of quality decking oil. Because spotted gum is a premium timber, most owners use premium oils — quality hardwood decking oil for a 30m² deck costs $150–$300 in materials alone.

The process typically takes a full weekend for a mid-sized deck, and many homeowners hire professionals to ensure an even, high-quality finish. Professional oiling for a 30m² deck costs $400–$1,000 depending on your area.

What makes spotted gum maintenance particularly demanding is that skipping it is more visible than with other timbers. Spotted gum’s beautiful colour range is one of its primary selling points — when that colour greys out and the surface starts checking, the gap between how the deck looks and how it should look is stark. Many spotted gum owners report feeling locked into a maintenance cycle because they’ve invested in a premium product and can’t bear to see it deteriorate.

Maintaining Composite Decking

Composite decking maintenance is minimal: sweep debris and wash with soapy water 2–4 times per year. No oiling, staining, sealing, or sanding required, ever. The appearance you see on installation day is essentially the appearance you’ll have in 15 or 20 years.

This maintenance difference is often the tipping point for homeowners who’ve previously owned spotted gum. The timber looked stunning, but the annual oiling commitment — and the guilt when it was overdue — eventually drives them toward a material that looks great with minimal effort.

Composite Maintenance Guide →

Appearance: The Honest Comparison

This is where spotted gum holds its strongest advantage, and it’s worth being upfront about it. Freshly oiled spotted gum is one of the most visually striking decking materials available anywhere. The natural colour variation, wavy grain patterns, distinctive flecking, and warm depth of real timber create a look that no manufactured product fully replicates. If authentic natural beauty is your absolute top priority, spotted gum delivers it.

The qualifier is that spotted gum only looks like that when freshly maintained. Within weeks of oiling, the vibrancy begins to fade. Within 6–12 months without re-oiling, spotted gum transitions to a flat silver-grey that bears little resemblance to the deck you fell in love with. The beautiful colour that justified the premium price only exists with consistent, ongoing effort.

Modern composite decking has closed the appearance gap significantly. Advanced multi-tonal colour blending, realistic grain patterns, and natural colour variation create boards that convincingly replicate popular timber aesthetics — including spotted gum tones. Premium composite ranges offer warm honey and light brown colourways specifically designed to capture the spotted gum palette.

The key difference is consistency. Composite offers a more stable appearance over time without the regular oiling required by timber, subject to product selection, installation, and site conditions. There’s minimal effort to maintain the appearance, no greying, and no seasonal colour variation depending on when you last oiled.

Explore Composite Colour Options →

Tannin Bleeding and Gum Veins

Spotted gum produces moderate tannin bleeding — less severe than merbau, but still enough to stain surrounding concrete, pavers, and rendered surfaces, particularly in the first 6–12 months. The reddish-brown water runoff is most noticeable after rain and can be frustrating around pool areas and light-coloured hardscaping.

Spotted gum also contains natural gum veins — deposits of a dark, resinous substance within the timber. These gum veins are a natural characteristic of the species and are considered part of its aesthetic character, but they can occasionally weep a sticky residue, especially in hot weather. This is a cosmetic issue rather than a structural one, but it can be annoying underfoot and may attract dirt.

Composite decking eliminates both of these issues entirely. No tannin bleeding, no gum veins, no staining of surrounding surfaces — making it the cleaner, more predictable choice, particularly for pool surrounds and entertaining areas with light-coloured paving.

Safety Considerations

Splinters: Spotted gum is a dense, hard timber, but it can still develop splinters over time as the surface weathers and grain lifts between oiling cycles. Composite decking is completely splinter-free for its entire lifespan — a meaningful advantage for barefoot areas and homes with young children.

Slip resistance: Spotted gum can become slippery when wet, particularly once its surface oil wears off. Many composite decking products are manufactured with textured surfaces rated R11/P5 for consistent slip resistance, wet or dry.

Bushfire zones: Spotted gum naturally achieves BAL-29, making it suitable for bushfire-prone areas. Several composite products also achieve BAL-29 certification, including our NextGen Titanium range. Both materials are viable in bushfire zones.

Pool areas: Composite is the better choice for pool surrounds due to zero tannin bleeding, consistent slip resistance when wet, no splinters on bare feet, and no gum vein weeping near pool water.

Pool Decking Guide →

Sustainability and Sourcing

Spotted gum has a stronger sustainability story than most decking timbers. It’s Australian-grown, primarily from managed plantation forests and sustainably harvested native forests in NSW and Queensland. Certification through schemes like PEFC (Programme for the Endorsement of Forest Certification) is available, and the shorter transport distances compared to imported timbers reduce its carbon footprint.

However, any natural timber product involves harvesting trees that take decades to mature. Even sustainably managed spotted gum forests require significant time to regenerate, and growing demand has led to supply constraints and price increases in recent years.

Composite decking approaches sustainability differently. Made from recycled wood fibres and recycled plastics (typically post-consumer HDPE), composite diverts waste from landfill and reduces demand for virgin timber. The absence of ongoing chemical treatments — no oils, stains, or sealers entering the environment — is also an environmental advantage over the deck’s lifetime. Both materials have legitimate sustainability credentials, but through different pathways.

Installation: A Significant Difference

Spotted gum is one of the most challenging timbers to install. Its extreme hardness (11.0 kN Janka) means pre-drilling every screw hole is mandatory, drill bits and saw blades wear rapidly, and cutting is slow and physically demanding. The interlocked grain that makes spotted gum beautiful also makes it prone to chipping during cutting and difficult to achieve clean edges. Professional installers typically charge a premium for spotted gum compared to softer timbers.

Composite decking is significantly faster to install than spotted gum due to hidden clip fixing systems and consistent board dimensions. Hidden fastening systems eliminate pre-drilling entirely, boards are manufactured to precise and consistent dimensions, and cutting is quick with standard tools. For a 30m² deck, the installation time difference can be 2–3 days versus 4–6 days for spotted gum, translating to meaningful labour cost savings.

For DIY projects, the difference is even more pronounced. Spotted gum DIY installation requires quality tools, significant physical effort, and experience with hardwood to get a professional result. Composite’s hidden clip system is comparatively straightforward, making it the more accessible option for confident DIYers.

Installation Guide →

DIY Composite Decking Guide →

When to Choose Composite Over Spotted Gum

• Lifetime value is your priority — save $9,000–$24,000 over 20 years compared to spotted gum
• Maintenance freedom matters — no oiling, no staining, no weekends spent on upkeep
• You’re building near a pool or entertaining area — no tannin, no gum veins, no splinters
• Consistent long-term appearance — without oiling or staining
• Faster, more affordable installation — significantly lower labour costs
• You want a quality result without premium hassle — premium look, zero premium maintenance
  

When Spotted Gum Might Be the Right Choice

• Natural timber authenticity is non-negotiable — nothing fully replicates the look and feel of real spotted gum, and you’re committed to maintaining it
• You want an Australian-grown product — locally sourced native hardwood has an appeal that manufactured products don’t match for some homeowners
• Maximum scratch resistance — spotted gum’s extreme hardness outperforms composite for dent and scratch resistance
• You enjoy the maintenance ritual — some homeowners find oiling their deck a satisfying seasonal task

The Bottom Line

Spotted gum is a genuinely premium decking timber, and we have a lot of respect for it. Its natural beauty, extreme hardness, and local sourcing give it real advantages that shouldn’t be dismissed. If authentic Australian hardwood is what you want and you’re prepared for the maintenance and cost commitment, spotted gum is one of the best choices available.

For the majority of homeowners, however, composite decking delivers a better overall outcome. The upfront cost is lower, the lifetime cost is dramatically lower, the maintenance commitment is effectively zero, and modern premium composite captures much of the aesthetic appeal that draws people to spotted gum in the first place. When you factor in the 20-year cost difference of $9,000–$24,000 for a standard deck, composite is the smarter financial decision for most projects.

Our recommendation: Request free samples of both materials. See the composite options in the spotted gum colour range alongside real spotted gum. Many homeowners find the visual difference smaller than expected — and the cost and maintenance differences much larger.