Merbau vs Spotted Gum: Which Hardwood Is Best for Your Sydney Deck?
When it comes to Australian hardwood decking, two names keep coming up: Merbau and Spotted Gum. Both are durable, beautiful, and highly popular in Sydney. But they’re quite different timbers with distinct strengths, costs, and maintenance profiles. This guide compares them side-by-side so you can make the right choice for your home.
Quick Answer
Spotted Gum wins on aesthetics and consistency. Merbau wins on durability and longevity. For inner-city Sydney terraces, choose Spotted Gum. For coastal or high-traffic areas, Merbau is the safer bet. For unsure homeowners, Spotted Gum is more forgiving.
Hardness & Durability: The Head-to-Head
Both Merbau and Spotted Gum are Class 1 durable above ground, meaning they’ll last 25+ years with proper maintenance. But durability isn’t just about hardness.
| Janka Hardness | Merbau: 14.8 kN | Spotted Gum: 11 kN |
| Durability Class (above ground) | Both Class 1 (25+ years) |
| Termite Resistance | Merbau: Excellent | Spotted Gum: Good |
| Rot Resistance | Merbau: Excellent | Spotted Gum: Good |
| Moisture Movement | Merbau: Low (stable) | Spotted Gum: Moderate |
| Lifespan (real-world Sydney) | Merbau: 30-40 years | Spotted Gum: 25-30 years |
Winner: Merbau by a small margin. It’s fractionally harder and more resistant to environmental stresses. For commercial decks, high-traffic areas, or coastal properties within 500m of salt water, Merbau is the more conservative choice. Spotted Gum will still last decades—but Merbau has a longer proven track record under extreme Sydney conditions.
Aesthetics & Grain: Where They Shine Differently
This is where the two diverge dramatically. Durability matters, but so does how your deck looks in 10 years.
Spotted Gum: Wavy, interlocked grain with warm amber-to-chocolate tones. The grain is tighter and more consistent across boards. Under evening light, especially with fairy lights or uplighting, it has an unmistakable Sydney elegance. The colour is stable—it silvers gracefully if left untreated, or maintains warm amber tones if oiled regularly.
Merbau: Coarser, straighter grain with darker chocolate-brown tones. It can look heavier and more corporate. The real issue: Merbau can bleed red-brown tannins (especially in the first 6-12 months after installation), which can stain pavers, concrete, or light-coloured stone nearby. This isn’t a defect—it’s natural—but it requires management.
Winner: Spotted Gum for residential aesthetics. If your deck is visible from the house and you want warmth and character, Spotted Gum photographs better and feels more at home in a heritage or contemporary terrace. Merbau suits modern minimalist builds and high-performance commercial settings.
Maintenance: The Real Cost Difference
Both need regular oiling. But Merbau demands more attention in the first year.
Spotted Gum Maintenance:
- Oil every 12-18 months to maintain colour
- Clean boards before oiling (pressure wash or hand scrub)
- First coat within 4-6 weeks of installation (we do this)
- No special tannin management required
- Easier for DIY maintenance
Merbau Maintenance:
- Oil every 12-18 months (similar to Spotted Gum)
- Pre-oiling tannin extraction for first coat (soak boards in water 24-48 hours, drain, then oil)
- Monitor surrounding pavers/concrete in first year—tannin bleed can stain
- First oil coat is more critical to prevent tannin bloom
- More demanding for DIY—professional application recommended
Winner: Spotted Gum for maintenance ease. If you prefer hands-off or budget-conscious maintenance, Spotted Gum is simpler. Merbau isn’t difficult, but it has more variables in year one.
Cost Comparison
Both are premium hardwoods, so expect similar pricing. In Sydney right now:
Spotted Gum: $45-55 per linear metre (decking only) | $500-700/m² installed
Merbau: $48-58 per linear metre (decking only) | $550-750/m² installed
The difference is minimal—roughly 5-10%. The real cost variable is size, complexity, and site access. A 20m² courtyard deck with the tree in the middle will cost more regardless of timber choice.
Winner: Tie. Price them both. Pick based on other factors.
Which Timber for Your Situation?
Choose Spotted Gum if:
- You have a terrace, courtyard, or character home (inner-city Sydney, Paddington, Glebe, Newtown, etc.)
- Aesthetics and ambience matter (you’ll use the deck regularly)
- You prefer lower-maintenance oiling routines
- You’re building a smaller to medium deck (under 30m²)
- You plan to oil the deck regularly (every 12-18 months)
Choose Merbau if:
- You’re building a high-traffic or commercial deck
- Your property is within 500m of salt water (coastal durability matters)
- You want maximum longevity (30-40 year lifespan)
- You’re building a large deck (over 40m²)
- You prefer darker, more formal aesthetics
- You can commit to professional maintenance in the first 12 months
Ready to Build?
Spotted Gum or Merbau—both are right. The choice depends on your home, your lifestyle, and how hands-on you want to be. We’ve built hundreds of decks with both timbers across Sydney.
Get a free quote and let’s talk through which timber suits your space.
The Bottom Line
There’s no universally “best” hardwood. Merbau is the tougher, more durable choice for coastal or commercial settings. Spotted Gum is the warmer, more visually striking choice for residential living spaces. Both will outlast you if maintained properly.
In our experience, most Sydney homeowners gravitate toward Spotted Gum for residential projects and Merbau for beachside or high-use builds. The fact that you’re comparing them means you’re thinking seriously about quality—and that’s the right approach.
Ready to move forward? Call 0433 334 415 or book a free site visit. We’ll assess your space, soil conditions, shade patterns, and aesthetics—then recommend the timber that’ll make your deck a space you actually use.
Licence: 395250C (NSW Builder’s Licence)
