Box, Grey

Grey box is a highly durable Australian hardwood often used for heavy construction applications and flooring.

Other Names

Gum-topped Box, Eucalyptus Microcarpa, Eucalyptus Woollsiana, Eucalyptus Hemiphloia

Botanical Name

Eucalyptus moluccana

Common Form
Sawn
Species Type

Grey box is a tough, highly durable medium-sized Australian hardwood. It originates from the central and north coast districts of New South Wales and southern Queensland. Grey box, Eucalyptus woollsiana also occurs in parts of Victoria and South Australia.

Its heartwood is a pale, yellowish brown with the sapwood paler in appearance. It has a fine, even texture and usually features an interlocked grain. Gum veins are rarely present.

Grey box is a highly dense species, so it is quite difficult to work. It can be painted, stained and polished. Any machining or surface preparation should be done immediately prior to gluing. It is slow to dry but generally will not develop any surface checking.

Grey box is used for heavy construction, flooring, round timber wharfage, sleepers and shipbuilding.

It is mainly available in the areas in which it grows.

Shrinkage

Very Low Low Medium High Very High

Tangential :

7.40%

Radial :

3.30%

Unit Movement Tangential:

0.43%

Unit Movement Radial:

0.23%

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:

F27

F17

F14

F11

F8

Seasoned:

F34

F27

F22

F17

F14

Density per Standard

Seasoned:

1105kg/m3

Unseasoned:

1230kg/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:

98

Modulus of Rupture - Seasoned:

143

Modulus of Elasticity - Unseasoned:

13

Modulus of Elasticity - Seasoned:

16

Maximum Crushing Strength - Unseasoned:

50

Maximum Crushing Strength - Seasoned:

78

Impact - Unseasoned:

19

Impact - Seasoned:

15

Toughness - Unseasoned:

Toughness - Seasoned:

Hardness - Unseasoned:

11

Hardness - Seasoned:

15

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:

Susceptible

Lyctid Borer Susceptibility - Other:

Termite Resistance:

Resistant

Fire Properties

Critical Radiance Flux - Lower:

2.2 and <4.5

Critical Radiance Flux - Higher:

≥4.5

Smoke Development Rate:

<750

Average Specific Extinction Area:

<250

Bushfire Resistance:

BAL 12.5 and 19 – All AS3959 required applications
Appearance

Grey box has heartwood that is a pale, yellowish brown with the sapwood paler in appearance. It has a fine, even texture and usually features an interlocked grain. Gum veins are rarely present.

Grey box is very similar in appearance to coast grey box.

Common Applications

Tough and highly durable, grey box is mainly used for heavy engineering construction and flooring.

It is also used for cladding, bridges, wharves, shipbuilding, piles, poles and sleepers. Grey box is also an excellent fuel wood.

Workability

Grey box is a highly dense species so it is quite difficult to work. It can be painted, stained and polished. Any machining or surface preparation should be done immediately prior to gluing. It is slow to dry but generally will not develop any surface checking.

Origin of timber
NSW
Readily Available
NSW
Grey box is mainly available around the areas in which it grows. It is primarily available as flooring and construction material. Check with local suppliers for further information.
Source of timber
Native Forest
Image

Structural Timber Poles

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.
Image

Flooring

The warmth, strength and natural beauty of timber flooring is enduringly popular in a wide variety of domestic, commercial and industrial applications.

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