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
Softwood
  • Overview

    • 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
    Check mark Check mark Check mark

    Tangential : Provides a simplified rating for tangential shrinkage. This is the measure of the percentage reduction in dimension from the unseasoned to 12% moisture content condition.
    4.60%

    Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value
    2.60%

    Unit Movement Tangential: This is the percentage of dimensional change for each 1% moisture content change between about 3% moisture content and the fibre saturation point for the particular species.
    0.26%

    Unit Movement Radial: This is the percentage of dimensional change for each 1% moisture content change between about 3% moisture content and the fibre saturation point for the particular species.
    0.15%

    Strength Group Strength groups are given for unseasoned (S1-S7) and seasoned (SD1-SD8) timber in accordance with AS 2878. S1 and SD1 yield the highest strength and stiffness whereas S7 and SD8 yield the lowest.

    Very High

    High

    Reasonably High

    Medium High

    Medium

    Reasonably Low

    Low

    Very Low

    Unseasoned:

    S1

    S2

    S3

    S4

    S5

    S6

    S7

    S8
    Check mark

    Seasoned:

    SD1

    SD2

    SD3

    SD4

    SD5

    SD6

    SD7

    SD8
    Check mark

    Stress Grade A stress grade is defined in AS 1720 as the classification of timber for structural purposes by means of either visual or machine grading. The stress grade indicates the basic working stresses and stiffnesses to be used for structural design purposes. Measured in MPa.

    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 density is based on moisture content of 12%. Unseasoned density is an approximation as it depends on the moisture content at the time of measurement. Measured kg/m3.

    Seasoned:

    550kg/m3

    Unseasoned:

    700kg/m3

    Joint Group The joint group is a classification of the strength of a species in joint design. The values are from 1 (very high strength) to 6 (very low strength).

    Very High

    High

    Reasonably High

    Medium

    Low

    Very Low

    Unseasoned:

    J1

    J2

    J3

    J4

    J5

    J6
    Check mark

    Seasoned:

    JD1

    JD2

    JD3

    JD4

    JD5

    JD6
    Check mark

    Colour The colour of seasoned heartwood can vary between species and often within a species. The information provided should be used as a general guide only. In most cases, the colour of sapwood is either a lighter shade of the heartwood or a white/cream colour.

      White, yellow, pale straw to light brown Pink to pink brown Light to dark red Brown, chocolate, mottled or streaky
       
    Check mark

    Mechanical Properties

    Modulus of Rupture - Unseasoned: This property is a measure of maximum stress which timber can momentarily sustain when loaded slowly and continuously as a beam. Measured in MPa.
    47-53

    Modulus of Rupture - Seasoned: This property is a measure of maximum stress which timber can momentarily sustain when loaded slowly and continuously as a beam. Measured in MPa.
    82-90

    Modulus of Elasticity - Unseasoned: This property is of importance in determining the deflection of a beam under load — the greater the stiffness, the less the deflection. Measured in GPa.
    8-11.1

    Modulus of Elasticity - Seasoned: This property is of importance in determining the deflection of a beam under load — the greater the stiffness, the less the deflection. Measured in GPa.
    10.3-13.6

    Maximum Crushing Strength - Unseasoned:

    Also referred to as compression strength. This property measures the ability of the timber to withstand loads applied on the end grain. Measured in MPa.
    21.4-26.7

    Maximum Crushing Strength - Seasoned: Also referred to as compression strength. This property measures the ability of the timber to withstand loads applied on the end grain. Measured in MPa.
    43.0-51.3

    Impact - Unseasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.

    Impact - Seasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.

    Toughness - Unseasoned: This is a measure of timber’s ability to resist shocks and blows, and is synonymous with impact strength. It is measured in Nm.
    Low - up to 15 Nm

    Toughness - Seasoned: This is a measure of timber’s ability to resist shocks and blows, and is synonymous with impact strength. It is measured in Nm.
    Low - up to 15 Nm

    Hardness - Unseasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    2.10- 2.2

    Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    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: Durability is defined as the inherent resistance of a timber species to decay, or to insect or marine borer attack. All references to durability refer to the heartwood only. A scale of low to high (durability class 4 = low; 1 = high) has been adapted for above and in-ground durability.

    		 Check mark
    (0 - 7 yrs) (7 - 15 yrs) (15 - 40 yrs) (More than 40 yrs)

    Above ground: Durability is defined as the inherent resistance of a timber species to decay, or to insect or marine borer attack. All references to durability refer to the heartwood only. A scale of low to high (durability class 4 = low; 1 = high) has been adapted for above and in-ground durability.

    		 Check mark
    (0 - 20 yrs, usually < 5) (21 - 40 yrs) (41 - 64 yrs) (More than 60 yrs)

    Marine Borer Resistance: Indicates whether a species is resistant (R) or not resistant (NR) to marine borer attack.

    		 Check mark

    Lyctid Borer Susceptibility: Indicates whether a species is susceptible (S) or not susceptible (NS) to lyctid borer attack.

    Not Susceptible

    Lyctid Borer Susceptibility - Other:

    Termite Resistance: Indicates whether a species is resistant (R) or not resistant (NR) to termites.

    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: A measure of the tendency of a material to ignite measured on a scale of 0 – 20. An index of 0 indicates that the material did not ignite during the 20 minutes that the test takes. An index of 20 indicates that the material ignited in the first minute.
    0 1 2 3 4 5 6 7 8 9 10

    EFH Spread-of-Flame Index: This is a material's propensity to burn rapidly and spread flames based on a scale of 0 to 10 where 0 means that the materials will not cause flames to reach the ceiling and 10 indicates that the material could be expected to cause flames to reach the ceiling of a room within 10 seconds of ignition.

    EFH Smoke-Developed Index:This is a measure of the concentration (measured by optical density) of smoke a material emits as it burns. It is based on an arbitrary scale of 0 to 10. The higher the index, the greater the hazard from smoke is likely to be.
    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: This value is determined by the volume of smoke measured over the mass loss of the tested sample per test carried out in accordance with ‘Cone Calorimeter Test’ AS/NZS 3837. It is measured in units of m2/kg.
    < 250

    Bushfire Resistance: Naturally bushfire-resisting timbers are those with inherent bushfire-resisting properties. Some species have been tested and a number are in the process of being tested and are measured by Bushfire Attack level (BAL). BAL -12.5: Ember attack, BAL – 19: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 12.5 and 19 kWm3, BAL – 29: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 19 and 29 kWm3.
    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
    a kitchen with wooden cabinets and a countertop

    Joinery

    Timber joinery offers a classic, stylish touch to any interior or exterior space.
    a reception desk in a building

    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
    a patio with a deck and chairs

    Pergolas

    A timber pergola is a practical, functional and attractive way to extend living and entertainment spaces into the outdoors.
    a house under construction with a roof

    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.

    Are you looking for a supplier?

    Start Your Search

    Social Media Feeds