Timber Species: Grey Ironbark (Eucalyptus paniculata)
Dry Density: 1090 kg/m³
Janka Hardness: 14 kN
These properties are only a guide, as timber is a natural product there will be variations within any species. The Janka Dry Hardness rating measures the hardness of the wood. The higher the number the harder the wood.
Description of Species:
Common in eastern New South Wales, the Grey Ironbark – sometimes called the white ironbark or simply ironbark – features a dark trunk with furrowed bark, an average height of between 20 and 30 meters, and fragrant flowers that are popular choices for honeybees and other insects yet is also highly resistant to the lyctus borer, a particularly pernicious parasite that enjoys ruining otherwise healthy trees. While it may be a bit on the shorter side, there have been some reports of grey ironbark trees growing as tall as 56 meters high and with trunk diameters of 1.9 meters. The tree prefers sandy loam and other types of highly fertile soil but has been known to grow perfectly well on high ridges with stony soil as well.
Another member of the eucalyptus family, the grey ironbark lives up to its name thanks to its exceedingly tough and hard exterior, though it needs to be kiln-dried to achieve its fabled hardiness. Janka ratings of an impressively high 14 and a denseness of an average 1090 kg/m³ provide this tough wood with plenty of longevity, making it ideal for not just flooring in high-traffic areas but for construction materials where density and hardiness like cross-arms, utility poles, and engineering projects. Additionally, grey ironwood is a popular choice for archery aficionados because of its durability in standing up to the rigors of being strung into a bowed shape.
Coloration ranges from a nutty honey to a dark chocolate, with dark red a common variation. Sapwood is often deep crimson, with heartwood usually lighter. Its grain is interlocked, moderately coarse, but even, contributing to its hardness and inherent beauty. Because of its extreme density and impact resistance, ironwood can sometimes be difficult to work with as an engineered flooring product. Instead it’s most often seen as solid timber flooring, parquetry, and decking.
Technical Properties of Grey Ironbark
Janka (Hardness) Rating – Dry
Natural Durability Class
Outside above ground contact
Critical Radiant Flux
Smoke Development Rate
Naturally bushfire-resisting Timber
>2.2 and <4.5
Tangential Shrinkage %
Naturally Termite Resistant to AS3660
R = Resistant
NR = Non resistant
Naturally Lyctus Susceptible
S = Susceptible
NS = Non susceptible