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Kapur

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An imported timber with a reputation for durability, in Malaysia and Indonesia kapur is a large hardwood used for general construction and as an internal and external finishing material. It has a similarly broad range of applications in Australia.

Sourced in the tropical lowland rainforests of Malaysia and Indonesia, kapur trees can grow to 60m in height and to a diameter of between 80 and 100cm. Well-formed buttresses support their straight, cylindrical bole and the trunk is free of branches for up to 30m. The bark is grey brown or dark brown with shallow fissures. When freshly cut, the timber releases a camphor-like odour but is not moth repellent or resistant to termites.

Kapur wood exhibits a class 2 durability, making it ideal for use in general construction. It makes an attractive material for flooring and staircases. The timber is also highly prized for external joinery, in particular for door and window sills, as it is resistant to decay when fully exposed to the weather.

This timber is not recommended for in-ground use (durability in ground class 3). Often preferred for external decking, it can also be used to create sturdy outdoor furniture. Kapur wood requires no finishing and will not rot when left outdoors where rain and sun will damage other lesser quality woods. Left untreated, kapur will weather to a soft warm shade of gray similar to the weathering of teak. It can also been used decoratively to create internal fittings, plywood, joinery and lining, as it displays a striking figure.

Appearance

Kapur timber is lustrous with sapwood that is clearly distinct from heartwood. The sapwood ranges from almost white to light yellowish brown in colour and is clearly demarcated from the heartwood, which is red to reddish brown. Kapur wood exhibits variable grains from straight to spiral, to deeply interlocked grains that create a striking figure. The wood has a moderately coarse to even texture.

Common Applications

Kapur is suitable for general construction: posts, beams, joists, rafters, fender supports, telegraphic and power transmission posts and cross arms. It is used in door and window frames and sills, flooring, staircases and internal joinery. It can be used to make pallets (heavy and permanent types), tool handles (impact), internal plywood, laboratory benches and columns (light duty). In domestic flooring and internal fittings where a finished appearance is important, care should be taken in fixing because of its tendency to develop an unsightly black stain in contact with iron nails, screws or other fittings.

Common Form

Sawn

Workability

Kapur's working properties are good with a moderately hard rating (rated 3). The timber machines well, being easy to re-saw and cross-cut when green, but more difficult when dried. There is a moderate blunting effect on cutting edges caused by the presence of silica in the timber, which can be severe where the grain is interlocked. The material tends to break out at the bottom of cuts in cross-cutting and narrow band sawing. Planing is easy and produces a rough surface. Pre-drilling is recommended when nailing near extremities, but otherwise the timber takes nails and screws well. Polishing, staining and painting are also easy. Steam bending qualities are rated moderate as steaming operations release resin.

Origin of Timber

Asia

Readily Available

National

Availability - Further Information

The availability of this timber is limited, perhaps because the international trend towards sourcing timber from old growth rainforests has become unpopular in recent years. However, there is limited availability in Western Australia, South Australia, the Northern Territory and Queensland.

Availability - Further Information

Native Forest

Shrinkage

Very Low Low Medium High Very High

Tangential :

6.00%

Radial:

2.50%

Unit Movement Tangential:

0.37%

Unit Movement Radial:

0.19%

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:

F17

F14

F11

F8

F7

Seasoned:

F22

F17

F14

F11

F8

Density per Standard

Seasoned:

750kg/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:

82

Modulus of Rupture - Seasoned:

132

Modulus of Elasticity - Unseasoned:

16

Modulus of Elasticity - Seasoned:

21

Maximum Crushing Strength - Unseasoned:

46

Maximum Crushing Strength - Seasoned:

73

Impact - Unseasoned:

Impact - Seasoned:

Toughness - Unseasoned:

Low - up to 15 Nm

Toughness - Seasoned:

Medium - 15 - 24 Nm

Hardness - Unseasoned:

4.8

Hardness - Seasoned:

6

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:

Not 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:

1 - non-combustible 2 - reasonably non-combustible 3 - slightly combustible 4 - combustible

Fire Properties Group
Number:

Group Number - Other:

3 if used on MDF or particleboard ≥12mm; veneer thickness 0.6-0.85mm

Average Specific Extinction Area:

<250

Bushfire Resistance:

BAL 12.5 and 19 – 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.

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.

Windows

Timber windows are usually supplied as joinery items with a primer or base coat, as factory glazed components requiring site finishing or as fully glazed and finished windows.

Demand is ever increasing for high performance windows that promote efficient energy use in buildings. Careful window selection and placement is rightly viewed as a means of reducing demand for artificial light and climate control. Timber is an ideal material when considering these aspects as it is a material that is light, strong, natural and renewable. It can be moulded to any shape, so will meet the thermal, acoustic and design requirements of even the most unusual window.

This guide discusses the common elements involved in specifying, constructing and installing timber windows

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