Western Red Cedar: The Premium Wood for Durable and Stylish Applications
The Wood Guide · The wood register
Softwood · referenceWestern Red Cedar
From the rainforests of British Columbia: a tree that can live for a thousand years and yields wood that is light, fragrant and naturally rot-resistant.
- Thuja plicata
- ±370 kg/m³ — very light
- Class 2 · usable untreated
Western Red Cedar
From the rainforests of British Columbia: a tree that can live for a thousand years and yields wood that is light, fragrant and naturally rot-resistant.
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A giant from the rainforest
Western Red Cedar grows between the 39th and 57th parallels, with its centre of gravity in the Canadian province of British Columbia. Its range runs from Alaska to California, from the coastal rainforests to the Rocky Mountains.
Up to 70 metres tall
In favourable conditions the tree grows into a true giant.
Up to 4 metres thick
Measured at breast height — trunks of that size are unthinkable in Europe.
More than 1,000 years old
The oldest specimens were already standing when our medieval cathedrals were being built.
The old-growth forests where Western Red Cedar grows consist of about 40% of this species and 60% hemlock. That makes them an ecologically diverse and important reserve — all the more reason to ask about the origin of the timber when you buy.
Botanically, by the way, Western Red Cedar is not a cedar at all: it belongs to the cypress family. The name comes from its scent and properties. The full story of that naming confusion is in what is cedar wood.
Natural properties
Lightweight but strong
With an average density of 370 kg/m³, this is one of the lightest durable woods there is — about half the weight of oak.
Naturally resistant
The heartwood contains thujopsene and related substances that keep fungi and insects at bay. No treatment needed to survive.
Excellent insulator
Its low thermal conductivity makes it attractive as a facade and cladding material where insulation matters.
Rich colour variation
From light yellowish brown to chocolate brown, with a fine, straight grain — boards from the same batch differ noticeably.
The scent
Distinctive, pleasant and functional: the same substances that protect the tree also keep moths and mosquitoes away.
Technical properties
The figures show what the combination of light yet usable means in practice.
| Property | Value | What that means |
|---|---|---|
| Density | ±370 kg/m³ | Exceptionally light — easy to handle and install |
| Durability class | Class 2 (EN 350) | Durable: 15 to 25 years outdoors, untreated |
| Bending strength | 54 N/mm² | Sufficient for cladding and light structures, not for heavy spans |
| Modulus of elasticity | 8,000 N/mm² | Bends more easily than Douglas fir — keep spans short |
| Compressive strength (parallel) | 34 N/mm² | Limited load-bearing capacity under vertical load |
| Dimensional stability | Very good | Moves little with changing humidity |
That low density has a downside: Western Red Cedar is soft and gets damaged more easily than hardwood. For floors or surfaces that see a lot of walking or dragging, it is not the best choice. And it is less suitable for load-bearing structural parts.
What Western Red Cedar is used for
Cladding
The classic use: weather-resistant, stable and so light that the supporting structure barely notices it.
Decking and boardwalks
Rot-resistant and pleasant to walk on barefoot; it weathers elegantly to silver grey.
Pergolas and canopies
Light enough to install on your own, and it keeps its shape.
Roof structures and shingles
Cedar shingles are a centuries-old tradition in North America, precisely because of the combination of lightness and rot resistance.
Interior cladding
Panelling and wall panels, where the scent and insulating effect come into play.
Saunas
A classic: the wood does not get too hot, it moves little, and the scent is part of the experience.
Maintenance: let it grey or keep the colour
The same principle as with teak and Douglas fir — choose one and stick with it.
Almost no work
- Clean once a year with water and a soft brush.
- Durability stays the same — the greying is only on the surface.
- No pressure washer: this wood is soft and damages easily.
Touch up regularly
- Treat with an oil or a stain with UV filter.
- Every one to two years, depending on exposure.
- For gluing: PVA or resorcinol glue, because the extractives can interfere with other glues.
Frequently asked questions
Is Western Red Cedar a true cedar?
Botanically, no. Thuja plicata belongs to the cypress family, not to the true cedars of the pine family. The name comes from its scent and properties, which closely resemble cedar. More on that in what is cedar wood.
How heavy is Western Red Cedar?
About 370 kg/m³ — exceptionally light for a durable wood, and roughly half the weight of oak. That makes it popular for cladding and roof structures.
Do I need to treat it?
Not for durability: class 2 speaks for itself. Untreated, it weathers to silver grey. If you want to keep the reddish-brown colour, treat it regularly with an oil or a stain with UV filter.
Why is it more expensive than ordinary softwood?
Because of its origin and slow growth in the North American rainforests, and because of its properties: naturally durable, exceptionally light and dimensionally stable. For an affordable European alternative, look at Douglas fir.
Cedar in perspective
Western Red Cedar is a reference species in our register — wood we do not work with ourselves, but do know.
Have a question about your project? Just ask — we're happy to help.
Photos via Wikimedia Commons: Thuja plicata — Mike Trask, CC BY-SA 4.0 · Thuja plicata — Geordie.birch, CC BY-SA 4.0