Which Timber Decking Should Builders Choose?

Spotted Gum and Blackbutt are premium Australian hardwood decking options, each with its own pros and cons.

Spotted Gum decking is extremely hard-wearing and visually striking, making it ideal for high-traffic areas.
Blackbutt decking is consistent, reliable and easier to install, making it a popular choice and a strong option for BAL-rated projects.

Timber selection can directly influence the speed of installation, client expectations around colour variation, finish and long-term maintenance. This blog explains the difference between Spotted Gum and Blackbutt decking, and the benefits and pitfalls of both timber species.

Spotted Gum Decking (QLD & NSW)

Spotted Gum decking used with centralised fire pit.

Timber properties

Bushfire Rating BAL29
Durability Class 1 (Above Ground)
More than 40 years above ground and 15-25 years inground
Naturally resistant to termites
Low tannin content
Hardness 10.1 Janka Rating
Natural colour variation from light browns through to deep charcoal tones, depending on QLD or NSW Spotted Gum variants

Installation considerations

Pre-drilling recommended for Spotted Gum decking to high-density
Tougher on blades and fasteners compared to other hardwoods
Stainless steel fixings are essential, particularly in coastal environments
Correct board spacing is critical to manage natural movement

Finishing and maintenance

Accepts oils and stains well
Can be left to weather naturally or coated to retain colour
Regular oiling required to maintain colour consistency

Availability

Secure supply early for large or commercial decks
Spotted Gum decking is available in random and set lengths

Common Issues

End-splitting can occur if boards are not sealed
Colour variation, particularly in QLD variations

Blackbutt Timber Decking

Blackbutt decking used in pool/outdoor project.

Timber Properties

Durability Class 1 above ground
More than 40 years above ground
15-25 years in-ground
Natural resistance to termites
Hardness 8.9 Janka Rating
Bushfire Rating BAL29
Straight grain with a uniform appearance

Installation considerations

Blackbutt decking is easier to cut, drill and fix than denser hardwoods
Predictable movement when installed according to recommendations
High extractives and tannin in mature blackbutt timber

Finishing and maintenance

Accepts oils and stains evenly for a consistent finish
Can be left to weather naturally or oiled
Straightforward maintenance

Availability

Widely stocked in standard decking sizes
Available in random and set lengths
Reliable lead times for residential projects

Common Issues

Surface wear may show over time in very high-traffic areas
Blackbutt decking can surface check
Colour change will occur if left uncoated
Machines and holds fasteners well
Correct fixing and moisture management reduce the risk of cupping or movement

Bowens Extensive Timber Decking Range

Bowens offers high-quality Spotted Gum and Blackbutt timber decking options alongside Merbau decking, Tallowwood decking, Karri decking and more. Browse our range of timber decking online or in-store today.

To find other timber species that might be suitable for your next build, explore our blog, “Deck out the deck,” for a breakdown of their properties.

Spotted Gum vs Blackbutt Timber Decking

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