Gum, Mountain Grey

Mountain grey gum is a hard and moderately durable timber species. It is suitable for a range of applications including general construction, flooring, paneling and sleepers.

Other Names

Monkey Gum, Spotted Mountain Gum, Small-fruited Mountain Gum, Mountain Blue Gum, Eucalyptus cypellocarpa (formerly E. goniocalyx)

Botanical Name

Eucalyptus cypellocarpa

Common Form
Sawn
Species Type

Mountain grey gum is a medium to tall tree growing up to 65 metres in height on favourable sites. It occurs in the Grampian Ranges and around Cape Otway in Victoria, and on the coastal fall of the southern tablelands of New South Wales.

The wood of this species is a pale brown colour, often with pink or yellow tinges. Sapwood is generally paler, but not always visually distinct from the heartwood. Grain is typically straight and close, with occasional interlocking. Texture is moderately coarse and even, and gum veins are common.

Mountain grey gum timber is moderately durable. Untreated heartwood, although lacking termite-resistance, has an aboveground life expectancy of between 15 and 40 years. Untreated sapwood is susceptible to Lyctid borer attack.

Given the timber’s hardness, mountain grey gum is reasonably easy to work by hand or machine.

Common uses of mountain grey gum timber include bridge and wharf construction, general construction applications such as building framework, wheelwright work, sleepers, paneling and flooring. The timber has potential for furniture, joinery and veneer applications, although care is required in the selection of timber suitably free of gum veins.

 

Shrinkage

Very Low Low Medium High Very High

Tangential :

11.90%

Radial :

5.30%

Unit Movement Tangential:

0.39%

Unit Movement Radial:

0.27%

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:

F34

F27

F22

F17

F14

Density per Standard

Seasoned:

870kg/m3

Unseasoned:

1150kg/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:

75

Modulus of Rupture - Seasoned:

141

Modulus of Elasticity - Unseasoned:

14

Modulus of Elasticity - Seasoned:

18

Maximum Crushing Strength - Unseasoned:

39

Maximum Crushing Strength - Seasoned:

76

Impact - Unseasoned:

17

Impact - Seasoned:

18

Toughness - Unseasoned:

Medium - 15 - 24 Nm

Toughness - Seasoned:

Medium - 15 - 24 Nm

Hardness - Unseasoned:

7.0

Hardness - Seasoned:

10

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:

Not Resistant

Fire Properties

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

The wood of mountain grey gum is a pale brown colour, often with pink or yellow tinges. Sapwood is generally paler, but not always visually distinct from the heartwood. Grain is typically straight and close, with some interlocking. Texture is moderately coarse and even.

 

Common Applications

Common uses for mountain grey gum timber include general construction applications such as building framework, bridge and wharf construction, wheelwright work, sleepers, paneling and flooring.

 

Workability

Mountain grey gum is reasonably easy to work, however excessive gum veining can interfere with finishing procedures, and careful selection is required for decorative applications.

 

Origin of timber
NSW
Readily Available
NSW
Mountain grey gum timber products are commonly available in southern New South Wales and parts of Victoria. Commercial availability is limited in other Australian states.
Source of timber
Native Forest
Image

Retaining Walls (Landscaping)

When it comes to retaining wall, landscape design and construction, timber is the natural choice. A material that is durable, sturdy and reliable, it has natural aesthetics that help it blend seamlessly with the outdoors. Careful consideration during the specification and design process will facilitate the creation of a long lasting, durable and beautiful timber retaining wall that will complement its surrounding landscape for years to come.
Image

Flooring

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

Are you looking for a supplier?

Start Your Search

Social Media Feeds