Cedar, Western Red

Western red cedar is a large softwood that grows in British Columbia and some of the nearby western states of the USA. A versatile timber, it is commonly used for applications such as cladding, windows and joinery.

Other Names

Giant Arbor-vitae, British Columbia Red Cedar, Red Cedar, Canoe Cedar

Botanical Name

Thuja plicata

Common Form
Sawn
Species Type
Softwood
  • Overview

    • Western red cedar is a large softwood that grows in British Columbia and some of the nearby western states of the USA including Washington, Oregon, Montana and Idaho.

    Western red cedar will remain dimensionally stable under most weather conditions and is not prone to shrinkage or swelling. Due to its versatility, it can be used for both internal and external applications such as cladding, linings, joinery, windows and roofing shingles. Natural preservatives provide resistance to fungus and insect attack, while its low density offers very good thermal insulation qualities. Western red cedar also delivers impressive acoustic properties.

    Visually, western red cedar is favoured for its rich and inviting colours. The heartwood ranges from a pale brown through to a richer dark brown. The sapwood is a paler yellowish white colour. It has a fine texture and straight grain with growth rings often visible.

    A durable, yet soft timber, western red cedar has a good workability. It cuts, machines and glues well and can also be painted, stained and polished. Precautions should be taken when sanding western red cedar as the sawdust can cause irritation for some people.

    It nails and screws well, however if timber is damp it is corrosive to iron and copper, so hot-dipped galvanised nails/screws should be used where required, and any copper plumbing, fittings or sheathing isolated from contact with the wood.

    Western red cedar can be brittle along the end grain and sharp cutters are recommended due to its soft nature. It is not suitable for steam bending.

    Western red cedar is commonly available with significant quantities being imported into Australia.

    Shrinkage

    Very Low Low Medium High Very High
    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.
    2.30%

    Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value
    1.10%

    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.
    0.23%

    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.
    0.11%

    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:

    F7

    F5

    F4

    Seasoned:

    F8

    F7

    F5

    F4

    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:

    350kg/m3

    Unseasoned:

    490kg/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

    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.
    31-39 (35.9)

    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.
    49-55 (51.7)

    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.
    6.3-6.9 (6.5)

    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.
    6.95-7.7 (7.7)

    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.
    15.5-19.3 (19.1)

    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.
    34.6-38.6 (31.4)

    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.
    <1.75 (1.2)

    Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.
    <1.75 (1.6)

    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.

    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.

    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:

    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

    Western red cedar is favoured for its rich and inviting earthy tones. The true beauty of this durable softwood is most evident when used for appearance based applications such as external cladding and windows. The heartwood ranges from a pale brown or honey colour through to a richer dark brown, with older growth timber somewhat darker in appearance. The sapwood is a paler yellowish white colour. It has a fine texture and straight grain with growth rings often visible.

    Common Applications

    Western red cedar is used for applications such as cladding, linings, joinery, windows, doors and roofing shingles. Natural preservatives provide resistance to fungus and insect attack, while its low density also provides good insulation qualities. It can be used in many types of weather conditions due to its natural durability.

    Workability

    A durable yet soft timber, western red cedar has good workability. It cuts, machines and glues well and can also be painted, stained and polished. It also nails and screws well, however if timber is damp it is corrosive to iron, so hot-dipped galvanized nails/screws should be used where required.

    Western red cedar can be brittle along the end grain and sharp cutters are recommended due to its soft nature. Precautions should be taken when sanding western red cedar as the sawdust can cause irritation for some people. It is not suitable for steam bending.

    Origin of timber
    North America
    Readily Available
    NSW
    Western red cedar is commonly available with significant quantities being imported into Australia.
    Source of timber
    Native Forest
    a close-up of a house

    Shingles and Shakes

    A shingle, generated from a sawn piece of timber is characterised by its relatively smooth face and back, while in contrast a shake, essentially a split piece of timber, is dominated by a strongly textured surface.
    a kitchen with wooden cabinets and a countertop

    Joinery

    Timber joinery offers a classic, stylish touch to any interior or exterior space.
    a close-up of a garage door

    Doors

    Timber is one of the most popular and superior material choices for both internal and external doors.
    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 wood fence with trees in the background

    Fencing

    When it comes to fencing, timber is a natural choice. A material that is durable, strong and reliable it compliments almost every outdoor landscape and environment. Clear specification, detailed installation and appropriate maintenance will ensure a timber fence provides a natural and lasting property boundary and back drop for years to come.
    a close-up of a building

    Cladding, External

    The natural appeal, versatility and strength of timber makes it the superior choice for external cladding. Through specification, planning, design and finishing processes, timber cladding not only creates a building of superior strength, acoustic and thermal performance but also creates a place of beauty, style and natural appeal.
    a glass building with a wood deck

    Windows

    With natural aesthetic appeal, versatility and sound structural performance, timber provides excellent window joinery design options. Whether stained to bring out natural tones, or painted to compliment particular décors, timber windows can be tailored to suit a huge variety of styles and can be installed into any type of building.

    Are you looking for a supplier?

    Start Your Search

    Social Media Feeds