Blackbutt
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Other Names
Coastal Blackbutt, Pink Blackbutt
Blackbutt is a large Australian hardwood that is commonly used for structural and exterior applications. It is also used to produce plywood.
The common name blackbutt came about due to the tree's appearance after bushfire, whereby the buttress - or butt - was significantly darkened. It is also known as coastal blackbutt to distinguish it from the tableland species, New England blackbutt.
Due to its quick growth and versatility, blackbutt makes a good plantation timber. It is a commonly available commercial hardwood species in New South Wales and southern Queensland, often used for building framework.
The heartwood ranges from golden yellow to pale brown, although occasionally a slight pinkish colour may be present. The sapwood, which is not always easy to distinguish, is much paler in appearance and is resistant to attack by lyctid borer. Blackbutt has an even texture and generally straight grain making it appealing for interior use applications.
Blackbutt can be stained, painted or polished but there can be issues with painting because of its tendency to surface check. The high extractives of mature wood can cause problems with some adhesives, but this is much less of an issue with young regrowth wood. These extractives can also cause staining on painted surfaces exposed to the weather. Blackbutt machines well but is only fair for steam bending.
Blackbutt provides good fire resistance and is one of seven hardwood timber species that was found to be suitable by the Building Commission in Victoria for home construction in bushfire areas (provided it has a thickness greater than 18mm).
A strong, durable hardwood, blackbutt can be used for a range of structural, exterior and interior applications including framework, decking, flooring and poles.
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Botanical Name
Eucalyptus pilularis
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Preferred Common Name
Blackbutt
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Species Type
Appearance
Blackbutt has an even texture. The grain can be interlocked but it is generally straight, making it appealing for interior use applications such as flooring and joinery. The heartwood ranges from golden yellow to pale brown, although occasionally a slight pinkish colour may be present. The sapwood, which is not always easy to distinguish, is much paler in appearance. Small gum veins may also be visible.
Common Applications
Blackbutt is a versatile timber and is used for structural, exterior and interior applications. In New South Wales and southern Queensland it is very popular for timber framing but is also used for cladding, internal and external flooring, decking, joinery, landscaping and furniture. Blackbutt is also used in the manufacture of plywood.
Common Form
Sawn
Workability
Care needs to be taken when drying as blackbutt is prone to surface checking on the tangential surface. Blackbutt should not be re-conditioned as this will widen any surface checks. Blackbutt can be stained, painted or polished but there can be issues with painting because of its tendency to surface check. The high extractives of mature wood can cause problems with some adhesives, but this is much less of an issue with young regrowth wood. These extractives can also cause staining on painted surfaces after exposure to the weather. Blackbutt machines well but is only fair for steam bending.
Origin of Timber
Readily Available
Availability - Further Information
Shrinkage
| Very Low | Low | Medium | High | Very High | |
Tangential : |
7.30% |
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Radial: |
4.30% |
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Unit Movement Tangential: |
0.37% |
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Unit Movement Radial: |
0.26% |
Strength Group 
Very High |
High |
Reasonably High |
Medium High |
Medium |
Reasonably Low |
Low |
Very Low |
|
Unseasoned: |
S1 |
S2 |
S3 |
S4 |
S5 |
S6 |
S7 |
|
|---|---|---|---|---|---|---|---|---|
Seasoned: |
SD1 |
SD2 |
SD3 |
SD4 |
SD5 |
SD6 |
SD7 |
SD8 |
Stress Grade
| 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
Seasoned: |
900kg/m3 |
|---|---|
Unseasoned: |
1100kg/m3 |
Joint Group
Very High |
High |
Reasonably High |
Medium |
Low |
Very Low |
|
Unseasoned: |
J1 |
J2 |
J3 |
J4 |
J5 |
J6 |
|---|---|---|---|---|---|---|
Seasoned: |
JD1 |
JD2 |
JD3 |
JD4 |
JD5 |
JD6 |
Colour
| White, yellow, pale straw to light brown | Pink to pink brown | Light to dark red | Brown, chocolate, mottled or streaky | |
Mechanical Properties
Modulus of Rupture - Unseasoned: |
87 |
|---|---|
Modulus of Rupture - Seasoned: |
144 |
Modulus of Elasticity - Unseasoned: |
15 |
Modulus of Elasticity - Seasoned: |
19 |
Maximum Crushing Strength - Unseasoned: |
48 |
Maximum Crushing Strength - Seasoned: |
77 |
Impact - Unseasoned: |
21 |
Impact - Seasoned: |
20 |
Toughness - Unseasoned: |
Medium - 15 - 24 Nm |
Toughness - Seasoned: |
Medium - 15 - 24 Nm |
Hardness - Unseasoned: |
6.5 |
Hardness - Seasoned: |
8.9 |
Durability
| Low | Moderate | Reasonably High | High | |
| (0 - 5 yrs) | (5 - 15 yrs) | (15 - 25 yrs) | (more than 25 yrs) | |
In-Ground: |
||||
| (0 - 7 yrs) | (7 - 15 yrs) | (15 - 40 yrs) | (More than 40 yrs) | |
Above ground: |
||||
| (0 - 20 yrs, usually < 5) | (21 - 40 yrs) | (41 - 64 yrs) | (More than 60 yrs) | |
Marine Borer Resistance: |
Lyctid Borer Susceptibility: |
Not Susceptible |
|---|---|
Lyctid Borer Susceptibility - Other: |
|
Termite Resistance: |
Resistant |
Fire Properties
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | |
EFH Ignitibility: |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | |
EFH Spread-of-Flame Index: |
|||||||||||
EFH Smoke-Developed Index: |
Critical Radiance Flux - Lower: |
>2.2 and <4.5 |
|---|---|
Critical Radiance Flux - Higher: |
>2.2 and <4.5 |
Smoke Development Rate: |
<750 |
| 1 - non-combustible | 2 - reasonably non-combustible | 3 - slightly combustible | 4 - combustible | |
Fire Properties Group |
Average Specific Extinction Area: |
<250 |
|---|---|
Bushfire Resistance: |
BAL 12.5, 19 and 29 – All AS3959 required applications |
Joinery
Timber joinery products offer a classic, unique and stylish touch to any interior or exterior design. The products are produced for a variety of internal applications including door and window frames, cabinetry, skirtings, mouldings and architraves. When looking to the outdoors, joinery products range from decorative eaves and posts to eye-catching railings.
Many timber species are suitable for joinery products and care should be taken in selecting the perfect timber for the particular product and its intended finish. Rare and exotic species such as Teak and Rosewood can generate pieces of outstanding beauty but material cost and availability are also important considerations.
Commercially available species like Tasmanian oak, Australian cypress, spotted gum and the like, often make the more practical choice, with the added benefit that they can be easily matched with other timber products within the building, like flooring.
Solid timber for joinery products is generally supplied as ‘clear finish grade' but ‘paint grade' options are available and these are usually comprised of a composite material like MDF or glulam.
A large number of specialist suppliers and producers offer the consumer extensive choice of profiles for all of the most common and popular joinery products. Choice is in many cases, limited only by imagination.
Cabinetry is often associated with joinery and most typically includes, cupboards, benches and other similar ‘built in' furniture. Like joinery, cabinetry is generally specified as either paint or clear finish grade and naturally for clear finish grade timbers, appearance and surface finish are critical in achieving a successful application.
Decking
Download the WoodSolutions Technical Design Guide on Domestic Timber Decking here.
Timber decks are a practical and attractive addition to any outdoor landscape. Natural timber decks blend seamlessly with their surrounding environment and will serve as popular entertaining areas all year long.
As an external structure, carrying large loads of traffic, timber decking has high structural performance requirements. In addition decks are usually raised clear off the ground and fully exposed to the weather meaning an effective deck must be able to cope with wear and tear from repeated use and in addition discharge rainwater efficiently. Roundin the corners (easing the arris) of the decking will help run off water while spacing for ventilation between the decking boards will prevent water ponding on the deck surface.
Timber decking is available in both seasoned and unseasoned wood, in a wide range of species, sizes and grades. The natural appeal and strength of timber makes it a practical choice for outdoor decking. This guide provides an overview of best practice methods for specifying, installing and finishing a timber deck.
Mouldings
Timber mouldings add style, class and an elegant touch to any interior, offering a depth of beauty and warmth in a way only wood can. From period times to those more contemporary, timber mouldings have graced the most stylish and chic of interiors, decorating furniture, doors and windows. Decorative mouldings such as architraves, skirtings, cornices and ceiling roses remain an ever popular choice for designers seeking a finished result of beauty, style and quality. Like all timber products, mouldings are extremely versatile and durable, enhancing the aesthetics of any interior and functioning as the perfect finishing touch for designs with a focus on beauty and splendour.
Mouldings can be created from any commercially available species of timber and the moisture resistant wood product, MDF, is also a popular choice. When it comes to style and design, the sky is the limit with many suppliers offering custom matching to existing mouldings, as well as efficient supply of those that are individually designed. Installation is a breeze, with the majority of mouldings easily attached with a reputable wood adhesive. Finishes can be tailored by design requirements and the preferences of the end user, with mouldings commonly being both stained and/or painted.
Stairs, Exterior
All exterior stairs serve a functional purpose, but the choice of timber in the application will turn a functional building element into an aesthetically pleasing feature. And while the construction of stairs is demanding, the investment of time will be returned, with a well constructed timber staircase typically lasting decades.
Exterior stairs are usually built from treated softwood and durable hardwoods and typically finished with paint. The construction procedure described here applies to most general type stairs of either conventional or contemporary construction.
When it comes to stairs there is a multitude of variations available for application depending on the structural requirements of the building. This guide discusses the most commonly specified stair types.
Rails and Balustrades, Interior
The versatility, beauty and strength of timber makes it the ideal material choice for interior handrails and balustrades. Treated softwood and durable hardwoods are the most popular timber choices and these can be turned to create a range of unique styles and designs to suit a variety of tastes and decors.
When used internally balustrades and handrails are typically finished with a clear lacquer to showcase the natural beauty of the timber and with appropriate care and attention will last a lifetime. Find here general information on member sizes, connections and suitable materials, as well as important considerations, for the specification and construction of interior handrails and balustrades.
Stairs, Interior
Interior staircase work is considered a specialised area of carpentry and joinery as its construction requires high levels of workmanship, detail and accuracy. Many interior stairs are built from quality joinery timber, cut and seasoned especially for staircases. Interior stairs differ considerably in design, from simple straight flights, commonly used in domestic work, to more elaborate stairs, constructed purposely as stand out features in public and commercial buildings.
The construction procedure described here applies to most general type stairs of either conventional or contemporary construction.
Pergolas
Timber pergolas offer an attractive and economical way to create functional living and entertainment areas in the outdoors. Pergolas designed with care can maximise both winter sunshine and summer shade, ensuring outdoor living is enjoyed all year round. With its natural look, durability and versatility there are few other materials that can match the advantages of timber in pergola construction.
Pergolas are typically constructed via a straightforward post and beam process, which can be attached to an existing building or form a free standing structure. A protective finishing coat will preserve the life of the pergola and a variety of paints and stains are available on the market to facilitate this.
Rails and Balustrades, Exterior
The versatility, strength and natural beauty of timber makes it the ideal material choice for external handrails and balustrades. Usually built from treated softwood and durable hardwoods these timbers can be turned to create a range of styles and designs, resulting in balusters that are unique as they are individual. Painting, staining and oil based finishes broadly cover the wide range of finishing options available and with the appropriate care and attention a timber balustrade can last a lifetime.
This guide provides general information on member sizes, connections and suitable materials to enable the construction of a long lasting, attractive and durable timber handrail or balustrade.
Cladding, External
No other cladding material can offer the design freedom, ease of handling, range and natural beauty of timber. Timber cladding can create a building to suit almost any environment, taste or style.
Timber cladding has an inbuilt flexibility that provides natural advantages on sites subject to high winds, extreme climate, highly reactive soils, subsidence or earth tremors. And unlike masonry and other rigid materials, the natural resilience and high strength to weight ratio of timber enables it to withstand far greater stresses and movement.
Modern finishes give a long lasting and attractive appearance to timber cladding and can be used to change the colour and style of the building, making it a versatile material that will keep pace with changing tastes and fashions.
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.
Timber flooring is a timeless product, offering a warmth and natural beauty largely unmatched by other flooring options. This article provides an overview of the installation of solid timber strip flooring over bearers and joists, timber based sheet flooring products and concrete slabs. Timber flooring is typically supplied as either solid timber or laminated wood products, made from layers of bonded timber. It fits together with a tongue and groove joint and once in place, is sanded and finished. There is a wide variety of species to select flooring from and the right species for a given application will be dependent on numerous factors. Information relating to species selection, environmental assessment, finish selection and recommended maintenance routines are all provided in this section.
