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

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

Tangential :

2.30%

Radial :

1.10%

Unit Movement Tangential:

0.23%

Unit Movement Radial:

0.11%

Strength Group

Very High

High

Reasonably High

Medium High

Medium

Reasonably Low

Low

Very Low

Unseasoned:

S1

S2

S3

S4

S5

S6

S7

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:

F7

F5

F4

Seasoned:

F8

F7

F5

F4

Density per Standard

Seasoned:

350kg/m3

Unseasoned:

490kg/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:

31-39 (35.9)

Modulus of Rupture - Seasoned:

49-55 (51.7)

Modulus of Elasticity - Unseasoned:

6.3-6.9 (6.5)

Modulus of Elasticity - Seasoned:

6.95-7.7 (7.7)

Maximum Crushing Strength - Unseasoned:

15.5-19.3 (19.1)

Maximum Crushing Strength - Seasoned:

34.6-38.6 (31.4)

Impact - Unseasoned:

Impact - Seasoned:

Toughness - Unseasoned:

Low - up to 15 Nm

Toughness - Seasoned:

Low - up to 15 Nm

Hardness - Unseasoned:

<1.75 (1.2)

Hardness - Seasoned:

<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:

(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:

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:

Average Specific Extinction Area:

<250

Bushfire Resistance:

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
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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.
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Joinery

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

Timber is one of the most popular and superior material choices for both internal and external doors.
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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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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.
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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.
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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.

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