By MasterFloors on Sunday, 23 February 2014
Category: Technical Data

Jarrah

Botanical name
Eucalyptus marginata
Origin
Jarrah grows in the south-west corner of Western Australia.
Trading names
Jarrah
Appearance
Heartwood varies from rich reds to deep browns.
Sapwood pale yellow.
Texture somewhat coarse but even.
Grain generally straight although sometimes slightly interlocked producing a fiddleback figure.
General comment
Little degrade in drying if handled carefully.

Negligible collapse.

Despite its density it is relatively easy to work if tools are maintained in a sharp condition.

Glues satisfactorily.

Satisfactory for steam bending.

Care needed when nailing.

Common uses
Flooring, joinery, paneling, heavy furniture sleepers, poles, piles, heavy construction, domestic structural framing.
Properties
(See notes below)
Hardness rating
Average Hardness Rating - Dry: Hard

Lyctid Susceptibility of Sapwood
Susceptible
(source AS 5604)

Termite Resistance of Heartwood (inside above ground)
Resistant
(source AS 5604)

Marine Borer Resistance of Heartwood
Class 3
(source AS 5604)

Natural Durability Rating of Heartwood Above Ground
Class 2
(source AS 5604)

Natural Durability Rating of Heartwood In-Ground Contact
Class 2
(source AS 5604)
Notes

Density: 'Green Density' (GD) is the density of the wood at the time the living tree is felled. It varies considerably with the season, weather conditions, the age of the tree and so on; the quoted figure must therefore be accepted as a guideline only and when accurate green density figures are required for, say, assessment of transport costs, it is advisable to carry out accurate determinations on the materials involved.

'Dry Density' or 'Air Dry Density' (ADD) is the average density of the wood at 12 per cent moisture content. It too varies with conditions of growth, climate and maturity of wood.

There are published figures for both Green Density and Air Dry Density of most commercial species.

The figures given above have been rounded to the nearest 50.

Hardness rating: The hardness rating of a timber species is measured by the Janka Test. This is a standard test which measures the penetration into the timber of a common load and projectile. The results relate to a hardness capacity of the material and are expressed in kN. This information is useful where the timber may be subject to potential damage from impacts e.g. a dance floor. There are 2 sets of published figures; one for 'Green' or freshly felled timber and one for seasoned timber - i.e. timber with a moisture content of 12%.

The ratings given here are:
Soft - less than 5.5
Moderate - 5.5 to 7.0
Hard - 7.1 to 10.0
Very Hard - greater than 10.0.

Lyctid susceptible sapwood: Only the sapwood of some hardwoods is susceptible to lyctid borer attack. No softwoods are susceptible to attack.

Natural durability ratings: The natural durability rating of a timber species is a rating of the timber's resistance to attack by wood destroying fungi and wood destroying insects. The sapwood of all timber species has poor resistance and so the natural durability rating applies only to the heartwood of a timber species. The rating is based on the testing of stakes and poles embedded in the ground and on expert opinion of historical performance. There are 2 sets of ratings: one for above ground use and one for in-ground contact use. The lower the number the higher the performance in terms of durability. This information is useful for specifying material for external or exposed applications.

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