Botanical name:
Thuja plicata

Trading name:
Western Red Cedar

Appearance:
Heartwood: very pale brown to very dark brown.
Sapwood: yellowish white.
Texture: fine but uneven.
Grain: straight.
Growth rings: prominent.

Hardness rating:
Average Hardness Rating – Dry: Soft (less than 5.5 kN)

The hardness rating of a timber species is measured by the Janka Test. This is a standard test which measures the penetration into the timber of a common load and projectile. The results relate to a hardness capacity of the material and are expressed in kN.

Lyctid Susceptibility of Sapwood:
Not susceptible (source AS 5604).

Only the sapwood of some hardwoods is susceptible to lyctid borer attack. No softwoods are susceptible to attack.

Termite Resistance of Heartwood (inside above ground):
Resistant (source AS 5604)

Natural Durability Rating of Heartwood Above Ground:
Class 2 (source AS 5604)

Natural Durability Rating of Heartwood In-Ground Contact:
Class 3 (source AS 5604)

The natural durability rating is a rating of the timber’s resistance to attack by wood destroying fungi and wood destroying insects. The sapwood of all timber species has poor resistance and so the natural durability rating applies only to the heartwood of a timber species. The rating is based on the testing of stakes and poles embedded in the ground and on expert opinion of historical performance. There are 2 sets of ratings: one for above ground use and one for in-ground contact use. The lower the number the higher the performance in terms of durability.

General comments:

• Easy to dry. Easy to work but the sanding dust can be very irritating to the breathing passages, so a well-ventilated workshop is essential. It is rather brittle, so care is needed in working end grain.

• Glues well and is a good base for coatings.

• Since it is very soft there is a risk when dressing it that the cutters may compress the softer earlywood, which will later recover to produce a ridged surface.

• The damp wood is corrosive to iron, resulting in a black discolouration of the surrounding wood, so hot-dipped galvanised nails are commonly used in areas likely to experience any dampness.

• A yellowish colouring readily leaches from the wood, so white-painted woodwork at a lower level can be stained if storm rains penetrate, say, to the unprotected rear surface of cladding.

• Not resinous.

• If damp conditions are common, roof shingles and shakes may be subject to soft rot attack and some form of fungicidal treatment may be needed. A steep roof slope will be helpful by ensuring rapid drainage of rain and dew.

Source: timber.net.au