Fir, Douglas

Douglas fir is one of the world’s best-known timber species. Imported sawn timber products are readily available in Australia.

Other Names

Oregon Fir, Oregon Pine, Oregon, Green Douglas Fir, Blue Douglas Fir, Columbian Pine, Common Douglas, Coast Douglas Fir

Botanical Name

Pseudotsuga menziesii

Common Form
Sawn
Species Type

Douglas fir is one of the world’s best-known timber species. Native to the west coast of North America, it is forested extensively in timber plantations throughout Europe, New Zealand and South America – regions where the species has become naturalised. Sawn timber from this species is readily available in Australia.

The heartwood of Douglas fir ranges in colour from yellow through orange to a deep reddish brown. Sapwood is often distinctively paler, occurring in a band from 50 to 75 millimetres in width, depending on the timber’s source. Grain is generally straight, with a pronounced difference in colour between earlywood and latewood that results in a highly distinctive figure on back-sawn surfaces. Texture is often coarse and uneven.

The timber machines and turns well, but planer blades must be kept sharp in order to avoid surface ridging. Care is required with the use of standard fastenings and fittings, as nails may tend to follow the timber’s growth rings. Douglas fir can be satisfactorily bonded using standard glues and procedures. Due to the timber’s high resin content and occasional earlywood–latewood ridging of the dressed product, care is required in selecting timber for finishing applications and in preparation of surfaces for paints and varnishes.

Douglas fir is only moderately durable, and both sapwood and heartwood resist impregnation with preservatives. The timber lacks termite-resistance and sapwood is susceptible to lyctid borer attack.

Douglas fir is commonly found as sawn timber in weather-protected heavy construction applications such as mining timbers, posts and poles. Treated pilings and boards are used in marine structures and for landscaping. Other common applications include general house framing, flooring, lining, fascias, bargeboards and pergolas. It is also used in joinery, turnery, carving and plywood.

 

Shrinkage

Very Low Low Medium High Very High

Tangential :

4.60%

Radial :

2.60%

Unit Movement Tangential:

0.26%

Unit Movement Radial:

0.15%

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:

F11

F8

F7

F5

F4

Seasoned:

F14

F11

F8

F7

F5

Density per Standard

Seasoned:

550kg/m3

Unseasoned:

700kg/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:

47-53

Modulus of Rupture - Seasoned:

82-90

Modulus of Elasticity - Unseasoned:

8-11.1

Modulus of Elasticity - Seasoned:

10.3-13.6

Maximum Crushing Strength - Unseasoned:

21.4-26.7

Maximum Crushing Strength - Seasoned:

43.0-51.3

Impact - Unseasoned:

Impact - Seasoned:

Toughness - Unseasoned:

Low - up to 15 Nm

Toughness - Seasoned:

Low - up to 15 Nm

Hardness - Unseasoned:

2.10- 2.2

Hardness - Seasoned:

3.0 - 3.6

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:

Not Tested
Appearance

The heartwood of Douglas fir ranges in colour from yellow through orange to a deep reddish brown. Sapwood is often distinctively paler, occurring in a band from 50 to 75 millimetres in width, depending on the timber’s source. Grain is generally straight with a pronounced difference in colour between earlywood and latewood that results in a highly distinctive figure on back-sawn surfaces. Texture is often coarse and uneven.

Common Applications

Douglas fir is commonly found as sawn timber in weather-protected heavy construction applications such as mining timbers, posts and poles. Treated pilings and boards are used in marine structures and for landscaping. Other common applications include general house framing, flooring, lining, fascias, bargeboards and pergolas. It is also used in joinery, turnery, carving and plywood.

Workability

The timber machines and turns well but planer blades must be kept sharp in order to avoid surface ridging. Care is required with the use of standard fastenings and fittings, as nails may tend to follow the timber’s growth rings. Douglas fir can be satisfactorily bonded using standard glues and procedures. Due to the timber’s high resin content and occasional earlywood–latewood ridging of the dressed product, care is required in selecting timber for finishing applications and in preparation of surfaces for paints and varnishes.

Origin of timber
NSW
Readily Available
NSW
Douglas fir has been imported into Australia in large sections and long lengths for many years. It is readily available throughout mainland Australia.
Source of timber
Plantation
Image

Joinery

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

Timber panelling creates interiors as warm as they are stylish. Commonly using an MDF or plywood substrate, internal timber paneling is natural and versatile and comes as either solid natural timber panels or as sheets of engineered wood products
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Pergolas

A timber pergola is a practical, functional and attractive way to extend living and entertainment spaces into the outdoors.
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Framing

Since people began building simple shelters, wooden framing has played an important role in shaping structures of many kinds. One of the most popular types of wooden framing is known as lightweight timber construction.

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