Western Red Cedar

Thuja plicata

Commonly just called Western Cedar it is a large softwood, the largest of the North American Cedars although not a true Cedar, occurring in British Columbia, Washington, Oregon, Idaho and Montana. The specie has been regularly imported into Australia for many years and is widely available.

Timber Properties
Density(average)
380kg/ dry
Durability Class 2
Strength Group
S7 green
SD8 dry
Hardness Rating(average)
1.2kN green
1.5kN dry

The colour of the material varies with the heartwood ranging from pale to dark brown. Sapwood is yellowish white. Grain is generally straight with a fine texture and is not resinous.The material is quite soft and light making it very easy to handle so care is required to minimise marking in the handling and fixing.

Extractives in the wood increase the durability of the timber but are corrosive to metals such as iron and copper. This is enhanced when the material is wet creating black discolouration around fasteners due to the corrosive reaction. To minimise this affect, fasteners used externally should be hot-dipped galvanised. Avoid the use of uncoated steel or copper fasteners.

Western Red Cedar has been used extensively throughout Australia in applications such as cladding, trims, window and door frames, external joinery and roofing shingles. The material is well regarded for these applications with many outstanding designs incorporating this material. It is easily worked with tools and has a fairly low level of shrinkage. Some irritation can be caused by the dust so normal precautions should be made in regards to protective wear and ventilation. It glues well and offers a good base for coating systems. A yellowish colouring readily leaches from the product in exposed situations which may stain materials below the rain exposed timber.

Western Red Cedar is often left uncoated, greying off to a silky grey where exposed. Coating the material with a water repellent type stain or penetrating oil will increase the life of the product and minimise any discolouration around fasteners.