Kapur

Kapur is a large South East Asian hardwood with a broad range of applications including general construction and as an internal and external finishing material.

Other Names

Borneo Camphorwood, Keladan, Kapoer

Botanical Name

Dryobalanops Spp, principally D.aromatica

Common Form
Sawn
Species Type

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.

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

S8

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
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.

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
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.
Source of timber
Native Forest
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Joinery

Timber joinery offers a classic, stylish touch to any interior or exterior space.
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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.
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Rails and Balustrades, Interior

With its natural beauty and inherent strength, timber is a popular material choice for internal balustrades. Commonly built from treated softwoods and durable hardwoods, interior balustrades and handrails are typically finished with a clear lacquer to generate the most natural result.
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Stairs, Interior

Timber is the material of choice for designers seeking internal staircases of strength, beauty and durability.
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Windows

With natural aesthetic appeal, versatility and sound structural performance, timber provides excellent window joinery design options. Whether stained to bring out natural tones, or painted to compliment particular décors, timber windows can be tailored to suit a huge variety of styles and can be installed into any type of building.

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