Spotted Gum Decking

Overview

The common name “spotted gum” is used for four different highly durable and dense Corymbias (spotted gum was previously classified as a eucalypt, until it was changed in the mid-1990’s) that grow along the east coast of Australia, but more commonly refers to the species, Corymbia Maculata. They get their common name from the pale, smooth bark in the trees trunks that have shed in small patches leaving the tree with a “spotted” appearance. The different species commonly referred to as spotted gum only differ in appearance, not in durability or other properties. The heartwood of spotted gum ranges from a light brown to a dark reddish-brown. The sapwood of the timber is Lyctid borer susceptible, so is commonly treated to help keep the timber free of the bugs. The timber often comes with an attractive wavy grain with coarse and uneven texture; it also is noted as having a “greasy” feel when you run your hand over machined products. Spotted gum is grown throughout the eastern part of Australia and in some parts of WA and SA in both native forests and plantations. Spotted gum is currently QLD’s largest harvested native hardwood by volume, meaning that spotted gum is widely available throughout Australia, with quantities also being exported internationally.

Spotted Gum Decking
Spotted Gum Decking
Spotted Gum Decking
Spotted Gum Decking

 

Pros & Cons

PROS CONS
Readily available throughout Australia Expensive
1 of 7 hardwoods recommended by the building commission for bushfire prone areas Requires pre-drilling
Highly durable, dense, and hard Mostly supplied in random lengths
Widely available Lyctid borer susceptible
Little tannin leach
Sustainably sourced

 

Properties

Name Corymbia Maculata
Colour (Heartwood) Light brown to deep reddish brown
Colour (Sapwood) White to light brown
Durability Class 1
Density 990 kg/m3
Hardness Janka rating 11
Checking rating
Shrinkage rating
Availability Widely Available
BAL Rating 12.5
19
Termite Resistant YES
Lyctid Borer Susceptible YES
Tannin Leach Moderate
Origin VIC, NSW, QLD