Ironbark Decking

Overview

The common name “Ironbark” comes from the trees tendency to not shed its bark annually like many other eucalyptus, resulting in an accumulation of dead bark. This layer of bark protects the living tissue inside the tree from fires, and with a silvery-grey colour looks quite similar to iron metal and hence the name. Ironbark is usually seen growing, in both native forests and plantations, in the western area of NSW up to southern QLD, with some trees growing in northern VIC. Ironbark has a very high natural resistance to rot due to chemistry of the tree which helps fight off fungus. The heartwood has a deep red colour which is a great contrast to the pale yellow sapwood. Both heartwood and sapwood are often seen together in decking boards. Ironbark timber has an interlocked grain with a fine texture. Ironbarks popularity is ever increasing with more and more homes using the timber for decks, landscaping and cladding due to its high durability and fire resistance.

Grey Ironbark Decking
Grey Ironbark Decking
Red Ironbark Decking
Red Ironbark Decking

 

Pros & Cons

PROS CONS
High rot and termite resistance Hard to work
Very high durability, hardness and density Boards need to be pre-drilled
Widely available Expensive
Used for over 200 years in heavy construction Short oil life of decking due to density
Little tannin leach Mostly supplied in random lengths
1 of 7 hardwoods recommended by the building commission for bushfire prone areas Red ironbark is Lyctid borer susceptible

 

Properties

Name Eucalyptus Sideroxylon (red)
Eucalyptus Paniculata (grey)
Colour (Heartwood) Light grey / chocolate to deep red
Colour (Sapwood) Pale yellow
Durability Class 1
Density 1090 kg/m3
Hardness Janka rating 14
Checking rating
Shrinkage rating
Availability Readily Available
BAL Rating Grey
12.5
19
Red
12.5
19
29
Termite Resistant YES
Lyctid Borer Susceptible NO (grey)
YES (red)
Tannin Leach Little
Origin VIC, NSW, QLD