Tallowwood (Eucalyptus Microcorys)

Tallowwood is an extremely hard, durable and versatile Australian native hardwood species. Its timber products are suitable for a wide range of applications.

Tallowwood is a moderate to large tree occurring in wet sclerophyll forests of coastal regions from the Hunter River district of New South Wales to Maryborough and Fraser Island, Queensland.

The heartwood of this species ranges in colour from pale to dark yellow-brown, with occasional tinges of olive green. Sapwood is a whitish colour. The texture of Tallowwood timber is moderately coarse, generally with interlocked grain. Unusually for a eucalypt species, Tallowwood is free of gum veins. Figure is lacking but the timber possesses a distinctive lustre and ‘greasy’ appearance.

Tallowwood timber products exhibit exceptional durability in both in-ground and aboveground applications, where life expectancy is greater than 25 and 40 years, respectively. Although Tallowwood is highly resistant to decay and will withstand damp and wet conditions quite well, its sapwood is susceptible to Lyctid borer (powder post beetle) attack. Untreated timber of this species is equivalent to ‘fire retardant treated timber’ when tested in accordance with AS/NZS 3837.

Historically, Tallowwood has been used for bearings, mallet heads, mauls, wheel spokes, and tool handles. Current engineering applications include wharf and bridge construction (as sawn and round timber), railway sleepers, cross-arms, poles, piles and mining timbers. Construction uses range from unseasoned framing to dressed timber cladding, internal and external flooring, linings and joinery. Tallowwood is also used in fencing, landscaping and the construction of retaining walls. Decorative uses include outdoor furniture, turnery and joinery. Other applications include boat building, the construction of coaches, carriages and agricultural machinery, and structural plywood.

Botanical Name:

    Eucalyptus microcorys

Common Name:

    Tallowood

AKA:

    Tallow wood

Type:

    Hardwood

Appearance

The heartwood of this species ranges from pale to dark yellow-brown, in contrast to its typically whitish sapwood. The texture of Tallowwood timber is moderately coarse, generally with an interlocked grain relatively free of gum veins. Figure is lacking, but Tallowwood possesses a distinctive lustre and greasy appearance.

Common Applications

Historically, Tallowwood has been used for bearings, mallet heads, mauls, wheel spokes, and tool handles. Current engineering applications include wharf and bridge construction (as sawn and round timber), railway sleepers, cross-arms, poles, piles and mining timbers. Construction uses range from unseasoned framing to dressed timber cladding, internal and external flooring, linings and joinery. Tallowwood is also used in fencing, landscaping, and the construction of retaining walls. Decorative uses include outdoor furniture, turnery and joinery. Other applications include boat building, the construction of coaches, carriages and agricultural machinery, and structural plywood.

Common Form

Sawn

Workabiity

Tallowwood is very hard (rated 1 on a 6-class scale) in relation to indentation, yet is relatively easy to work with hand tools due to the timber’s natural greasiness – hence the species’ common name. It machines and turns well, readily accepts paint, stain and polish, and is amenable to the use of standard fittings and fastenings. Pre-drilling is recommended for nailing and screwing. Numerous extractives render Tallowwood difficult to bond satisfactorily, although success has been reported with the use of polyurethane glues.

Decking

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.

External Cladding

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.

Fencing

When it comes to fencing, timber is your natural choice. A material that is durable, strong and reliable it compliments almost every outdoor landscape and environment. Clear specification, detailed installation and appropriate maintenance will see any timber fence provide a natural and lasting property boundary and back drop for years to come.

Flooring

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.

Framing

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.

Internal Panelling

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

Pergolas

A timber pergola is a practical, functional and attractive way to extend living and entertainment spaces into the outdoors.

Retaining Walls (Landscaping)

When it comes to retaining wall, landscape design and construction, timber is the natural choice. A material that is durable, sturdy and reliable, it boasts natural aesthetics that help it blend seamlessly with the outdoors. Careful consideration during the specification and design process will facilitate the creation of a long lasting, durable and eye catching timber retaining wall that will complement its surrounding landscape for years to come.

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.

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.

SHRINKAGE

Very Low Low Medium High Very High
 tick
Tangential tooltip
 6.1
Radial tooltip
 3-4
Unit Movement tooltip
 0.37%

STRENGTH GROUPS

Very High High Reasonably High Medium High Medium Reasonably Low Low Very Low
Uneasoned
S1
S2
S3
S4
S5
S6
S7
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Seasoned
SD1
SD2
S3
SD4
SD5
SD6
SD7
SD8
 tick

STRESS GRADE tooltip

Structural No 1 Structural No 2 Structural No 3 Structural No 4 Structural No 5
Unseasoned
F27
F17
F14
F11
F8
Seasoned
F34
F27
F22
F17
F14

DENSITY PER STANDARD tooltip

Unseasoned 1230kg/m3
Seasoned 990kg/m3

JOINT GROUP tooltip

Very High High Reasonably High Medium Low Very Low
Unseasoned
J1
tick
J2
J3
J4
J5
J6
Seasoned
JD1
JD2
tick
JD3
JD4
JD5
JD6

COLOUR tooltip

White, Yellow,Pale Straw to Light Brown Pink to pink brown Light to dark red Brown, chocolate, mottled or streaky
Shade species_colour_bar_sm
tick

MECHANICAL PROPERTIES

Modulus of Rupture – Unseasoned tooltip
106
Modulus of Rupture – Seasoned tooltip
134
Modulus of Elasticity – Unseasoned tooltip
18
Modulus of Elasticity – Seasoned tooltip
18
Maximum Crushing Strength – Unseasoned tooltip
51
Maximum Crushing Strength – Seasoned
73
Impact – Unseasoned tooltip
20
Impact – Seasoned tooltip
17
Toughness – Unseasoned tooltip
Medium – 15 – 25 Nm
Toughness – Seasoned tooltip
Medium – 15 – 25 Nm
Hardness – Unseasoned tooltip
7.6
Hardness – Seasoned tooltip
8.6

DURABILITY

Low Moderate Reasonably High High
(0-5 years)
(5-15 years)
(15-25 years)
(> 25 years)
In Ground tooltip tick
(0-7 years)
(7-15 years)
(15-40 years)
(>40 years)
Above Ground tooltip
tick
(0-20 years, usually <5) (21-40 years) (41-64 years) (>65 years)
Marine Borer Resistance tooltip  tick
Lyctid Borer Susceptibility tooltip
Susceptible
Termite Resistance tooltip
Resistant

FIRE PROPERTIES

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
EFH Ignitability tooltip
 fire_arrow
fire_m
EFH Spread of Flame Index tooltip
1
2
3
4
5
6
7
8
9
10
fire_arrow
fire_m
EFH Smoke Developed Index tooltip
1
2
3
4
5
6
7
8
9
10
 fire_arrow
fire_m
Critical Radiance Flux – Lower tooltip
>2.2 and <4.5kWm 2
Critical Radiance Flux – Higher tooltip
> 4.5kWm 2
Smoke Development Rating tooltip
<750
Fire Properties Group Number tooltip
1 – Non Combustible
2 – reasonably non combustible
3 – slightly combustible
4 – combustible
fire_arrow
fire_m
Average Specific Extinction Area tooltip
<250
Bushfire Resistance tooltip
BAL 12.5, 19 and 29 – All AS3959 required applications