Spotted Gum (Corymbia Maculata)
Spotted Gum is a premium Australian hardwood that is used widely in structural, exterior and internal applications.
Spotted Gum is one of Australia’s premium native hardwoods with a striking appearance and a high degree of natural durability and strength, making it an ideal timber for a variety of structural, exterior and interior applications. Architects and designers throughout the world value Spotted Gum timbers for their back-sawn grain structure, attractive markings and vibrant colour palette.
Spotted Gum is the common name for four species that grow along the east coast of Australia, from northeast Victoria to the northern tablelands of Queensland, with some occurrence in western areas of southern Queensland. Sawn timber from these species is generally available throughout Australia. These species have straight, slender trunks with smooth bark that is shed in patches, giving the trees their characteristic spotted appearance.
The species referred to as Spotted Gum vary in appearance but not in durability class or other properties. The heartwood ranges from light brown through to dark red-brown hues. Sapwood is usually white to light brown in colour. The presence of a wavy grain can produce an attractive fiddle-back figure. The wood has a slightly greasy feel, a characteristic that aids machining and boring. Spotted Gum components that are 18mm thick or greater do not require fire retardant treatment for use in construction in bush-fire prone areas.
Spotted Gum is used in engineering applications such as wharf and bridge construction, railway sleepers, cross-arms and mining timbers. It is suitable for a range of building applications, such as posts and poles, framing, flooring, lining, decking and cladding. Spotted Gum is also used in the manufacture of veneer and plywood. Other applications include boatbuilding, tool and implement handles, polo sticks and diving boards. Compared to other Australian hardwoods, Spotted Gum is a minimal staining timber as it is less prone to bleed-through of tannins than other species. Spotted Gum is also a good timber for carving and woodturning.
|Very Low||Low||Medium||High||Very High|
|Very High||High||Reasonably High||Medium High||Medium||Reasonably Low||Low||Very Low|
|Structural No 1||Structural No 2||Structural No 3||Structural No 4||Structural No 5|
|Very High||High||Reasonably High||Medium||Low||Very Low|
|White, Yellow,Pale Straw to Light Brown||Pink to pink brown||Light to dark red||Brown, chocolate, mottled or streaky|
Modulus of Rupture – Unseasoned
Modulus of Rupture – Seasoned
Modulus of Elasticity – Unseasoned
Modulus of Elasticity – Seasoned
Maximum Crushing Strength – Unseasoned
Maximum Crushing Strength – Seasoned
Impact – Unseasoned
Impact – Seasoned
Toughness – Unseasoned
|High – 25 Nm and above|
Toughness – Seasoned
|High – 25 Nm and above|
Hardness – Unseasoned
Hardness – Seasoned
(> 25 years)
|(0-20 years, usually <5)||(21-40 years)||(41-64 years)||(>65 years)|
|Marine Borer Resistance|
|Lyctid Borer Susceptibility|
EFH Spread of Flame Index
|EFH Smoke Developed Index|
|Critical Radiance Flux – Lower|
>2.2 and <4.5kWm 2
|Critical Radiance Flux – Higher|
|Smoke Development Rating|
|Fire Properties Group Number|
1 – Non Combustible
2 – reasonably non combustible
3 – slightly combustible
4 – combustible
Group Number – Other
|For Plywood – Fire Properties – EFH Spread-of-flame Index: 7|
Average Specific Extinction Area
|BAL 12.5, 19 and 29 – All AS3959 required applications|
Lemon-scented Gum, Spotted Irongum, Eucalyptus maculata, Corymbia citriodora, Eucalyptus citriodora, Corymbia henryi, Eucalyptus henryi
Spotted Gum timbers are available in a range of colours depending on the location of the source forest. The heartwood ranges from light brown through definite browns to deep red-brown hues. Sapwood is white to light brown in colour and can be up to 50mm wide. Spotted Gum is a moderately coarse and uneven textured wood with some timbers having the additional feature of a wavy grain, giving rise to an attractive fiddleback figure.
Spotted Gum has a long history of usage in engineering applications such as wharf and bridge construction, railway sleepers, cross-arms and mining timbers. It is used for a variety of applications, including structural building members, such as posts and poles, and for framing, flooring, lining, decking and cladding. It is also used in boatbuilding and is the primary Australian timber used for the handles of tools and implements that are subject to high impact forces. Spotted Gum is a suitable carving and woodturning timber and is used in the manufacture of both indoor and outdoor furniture. Outdoor furniture in Spotted Gum has consistently won industry awards in Australia and is exported to a range of destinations around the world.
Spotted Gum machines well due to its natural greasiness and there is no difficulty using the timber with standard fittings and fastenings. As with most high-density species, machining and surface preparation should be done immediately before gluing. Spotted Gum readily accepts paint, stains and polish. It has a lower tannin content than most other eucalypts, therefore staining of paintwork or brickwork as a result of water running over unpainted timber surfaces is less likely to occur.
Architectural Roof Trusses
Architectural timber roof trusses create strong visual impact. Often used as part of ‘cathedral ceiling’ systems, timber can be specified light or heavy to suit the chosen theme and style. On finish, they can be left natural or may be oiled, stained, painted or highly decorated. Choice is limited only by individual style and design preferences.
Timber decking creates spaces that are functional, practical and aesthetically pleasing. With the right design and care a timber deck will make a valuable addition to any home or business, creating an outdoor living space that will be enjoyed for years to come.
Timber is one of the most popular and superior material choices for both internal and external doors. Whether manufactured from solid or engineered timber, there are many stylish and practical options that won’t compromise on strength and structural performance. A distinctive timber door can also create visual impact, adding value to any commercial or domestic building.
For outdoor applications, timber is one of the leading material choices. Timber use in external staircase applications creates structures of strength and durability, sheathed in a natural beauty that blends seamlessly with the outdoor environment.
The natural appeal, versatility and strength of timber makes it the superior choice for external cladding. Through specification, planning, design and finishing processes, timber cladding not only creates a building of superior strength, acoustic and thermal performance but also creates a place of beauty, style and natural appeal.
Whether for structural or finished flooring applications, timber offers durability, versatility and adaptability. The warmth, strength and natural beauty of timber flooring has proved enduringly popular in a wide variety of interior settings.
Since people began building simple shelters, wooden framing has played an important role in shaping structures of many kinds. One of the most popular types of wooden framing is known as lightweight timber construction.
Timber should be the material of choice for designers seeking internal staircases of strength, beauty and durability. The construction procedure described here applies to most general type stairs of either conventional or contemporary construction.
Timber paneling creates interiors as warm as they are stylish. Commonly utilising an MDF or plywood substrate, internal timber paneling is natural and versatile and comes as either solid natural timber panels or as sheets of engineered wood products
Structural Timber Posts
Timber poles are utilised in structural construction to provide support for gravity loads and resistance against lateral forces. Not only serving a structural function, timber poles provide many aesthetic benefits, with their use in construction often complementing architectural designs aimed at harmonisation with the natural environment.
Timber Joinery Products
Timber joinery products offer a classic, unique and stylish touch to any interior design.
Mouldings are extremely versatile and durable, enhancing the aesthetics of any interior and functioning as the icing on the cake for designs with a focus on beauty and splendour.
Timber Portal Frames
For buildings that require large spans and column free interiors, timber portal frames provide one of the most aesthetically pleasing solutions. Utilising modern engineering technology, portal frame design transforms timber into a highly effective, efficient and economical structural product. This application guide provides a comprehensive overview of the process of using timber in the specification, fabrication and erection of portal frame structures.