Ironbark Timber Guide

Everything you need to know about ironbark timber.

Ironbark Timber Technical Information

Red Ironbark (Eucalyptus sideroxylon)

Red Ironbark is extremely hard. Its colour varies from pale to rich reds as well as browns. The grain is usually interlocked, with a moderately coarse texture. It is extremely hardwearing and highly durable, allowing for wide range of external applications. However the timber is very hard to work, limiting some applications that require fine detailing. Red Ironbark is ideal for engineered structures that require excellent durability and strength, including wharf and bridge members, poles, railway sleepers, mining timbers. The timber is also suitable for all building construction materials from poles, framing, flooring, decking and cladding.

Physical Properties

  • Dry Density: 1090 kg/m³
  • Janka Dry Hardness: 13 kN

The Janka rating is the hardness level given to each species. The higher the number, the greater the hardness.

The natural colour variation within a timber species is normal and one of its most appealing attributes.

Colour Range Red
Janka (Hardness) Rating – Dry 13
Natural Durability Class In-ground contact 1
Outside above ground contact 1
Density (kg/m3) Unseasoned (Green) 1220
Seasoned (Dry) 1090
Strength Group Unseasoned (Green) S2
Seasoned (Dry) SD2
Joint Group Unseasoned (Green) J1
Seasoned (Dry) JD1
Fire Indices Spread-of-Flame Index 5
Fire Rating BAL29
Smoke-Developed Index 5
Critical Radiant Flux >2.2 and <4.5
Smoke Development Rate <750
Group Number 3
Naturally bushfire-resisting Timber Yes
Tangential Shrinkage % 6.3
Toughness (Nm) Naturally Unseasoned (Green) 17
Seasoned (Dried) 14
Naturally Termite Resistant to AS3660R = Resistant

NR = Non resistant

Naturally Lyctus SusceptibleS = Susceptible

NS = Non susceptible