Home / Species / Western Red Cedar

By Deepak Kumar · Founder, Vriksai

North America

Western Red Cedar

Also known as WRC, giant arborvitae, Pacific red cedar · Botanical Thuja plicata

Last updated: 15 July 2026Reviewed by: Vriksai editorial team — timber trade professionalsEditorial policy

Revision history

17 July 2026 — Data re-verified in site-wide audit (formulas, sources, durability classes)
15 July 2026 — Working properties and comparable-species data cross-checked against listed sources

🌲Softwood🌧Outdoor

Janka Hardness

350WD

lbf

Janka (metric)

1557calc

Hardness Class

Softcalc

Density

0.32fpl

g/cm³

MOE

7.7fpl

GPa

MOR

51.7FPL

MPa

Durability

Class 2

Durable

Fire (E84)

Class C

indicative

Thermal k

0.096

W/m·K

Green MC

90FPL

Fiber Saturation

28FPL

Radial Shrink

2.4WD

Tangential Shrink

5WD

T/R Ratio

2.08derived

Stability

Moderatecalc

About the fire rating. Indicative only, derived from density and published data — not a certified rating. Real performance depends on product, thickness, coating and installation. What our ratings do and do not certify.

Compare this wood:⚖ vs Deodar Cedar ⚖ vs Hinoki Cypress ⚖ vs Sugi Japanese Cedar ⚖ vs Thermally Modified Western Red Cedar All comparisons →

About Western Red Cedar

Western Red Cedar is a soft timber that works easily but bruises and dents in service, with a Janka hardness of 350 lbf (1,557 N) and a density of about 0.32 g/cm³. It grows in North America.

At 2.4% radial and 5.0% tangential the T/R ratio is 2.08 — typical, and manageable in exterior joinery and cladding provided the gaps are designed rather than assumed. Its fibre saturation point is near 28%. Below it movement is modest at 5.0% tangential, but the 2.08 T/R ratio means one-sided sealing will still pull a panel out of flat.

At 320 kg/m³ a cubic metre of Western Red Cedar weighs about 320 kg air-dry — that figure, the 5.0% tangential and 2.4% radial movement and the 350 lbf hardness are the three inputs the calculators below actually consume. Select Western Red Cedar in any of them to get species-specific results for weight, moisture, shrinkage and hardness.

Working properties

How Western Red Cedar behaves at the bench and on the machine, drawn from the USDA Forest Products Laboratory softwood records and North-American forestry references.

MachiningExcellent — light, soft and low in strength, it planes and shapes cleanly and sands to a smooth, satiny surface with sharp tools. Two habits to know: it can splinter when worked on end grain (mortising especially), and it is soft enough to compress under planing and moulding.

FasteningNails and screws well, but its holding power is only moderate given the low density. Never use bare steel fixings — the natural extractives corrode them and stain the wood; stainless or hot-dipped galvanised only.

GluingGlues easily and reliably.

FinishingTakes stain and paint satisfactorily and finishes well; prime properly before painting. Left bare it weathers to silver-grey, and properly finished cedar lasts decades even in harsh exposure.

Steam bendingNot a bending timber — too soft and brittle in section.

DryingDries easily and, once dry, is exceptionally stable — its very low shrinkage is a large part of why it stays flat as cladding.

Durability & use classification

Western Red Cedar heartwood is rated durable (EN 350 Class 2) for above-ground use. The reason is chemistry: the heartwood produces thujaplicins, natural fungicidal extractives that resist rot and fungi without any chemical treatment. Two caveats: it is not immune to termites and furniture beetles, and only the heartwood is durable — the narrow pale sapwood is not. It also resists preservative treatment.

Typical applications & suitability

Indoor Outdoor — The benchmark exterior softwood. Light, stable and naturally durable, it dominates cladding and roofing, but it is soft and low in strength, so it is a covering material, not a structural or high-wear one.

Documented end-uses: shingles and shakes (its single most important use), exterior siding and cladding, decking and fencing, poles, posts and piling, greenhouse construction, saunas and interior finish, ship and boat building, sash, doors and millwork, and boxes and crates.

Comparable species

Species closest to Western Red Cedar by density, hardness, stiffness and bending strength, computed directly from the Vriksai species dataset rather than hand-picked.

Paulownia280 kg/m³ · 300 lbf Kail Blue Pine450 kg/m³ · 460 lbf Norway Spruce430 kg/m³ · 380 lbf Spruce-Pine-Fir SPF420 kg/m³ · 510 lbf

Trade alternatives. For the same untreated-cladding brief, compare ThermoWood Western Red Cedar (thermally modified for extra stability), Accoya, or Sugi; for a durable hardwood route, Sweet Chestnut.

Alternatives to Western Red Cedar

Western Red Cedar measures 350 lbf Janka at 0.32 g/cm³, EN 350 durability Class 2, movement rated Moderate. Because Western Red Cedar is exterior-rated at Class 2, every candidate below is too. A substitute that quietly drops a durability class is the expensive kind of mistake. Read the numbers against the Janka scale and EN 350 durability classes.

Step up — harder than Western Red Cedar

For exterior joinery, cladding and garden work that also has to resist knocks. Harder means more dent resistance but heavier sections and more machining time.

ThermoWood Spruce Thermo-D380 lbf · 0.45 g/cm³ · Class 2+9% Janka · 0.45 g/cm³ · modified timber ThermoWood Pine Thermo-D540 lbf · 0.48 g/cm³ · Class 2+54% Janka · 0.48 g/cm³ · modified timber Thermally Modified Larch530 lbf · 0.55 g/cm³ · Class 2+51% Janka · 0.55 g/cm³ · modified timber

Similar, but more dimensionally stable

Cladding boards and exterior joinery live or die on movement. These give you less of it at equal or better durability. Size the gaps with the shrinkage predictor and EMC calculator.

Thermally Modified Western Red Cedar350 lbf · 0.38 g/cm³ · Class 2stability gained by modification, not by species · 2.0% tangential movement vs 5.0% · 1.0% radial movement vs 2.4%ThermoWood Spruce Thermo-D380 lbf · 0.45 g/cm³ · Class 2stability gained by modification, not by species · 1.0% radial movement vs 2.4% · 2.2% tangential movement vs 5.0%

Closest overall match

If Western Red Cedar is unavailable and the specification cannot change, these are the nearest substitutes across hardness, density, movement, stiffness, bending strength and durability class together — not on any single property. Lower distance means a closer match.

Deodar Cedarmatch 1.26580 lbf · 0.48 g/cm³ · Class 2580 lbf vs 350 · 0.48 vs 0.32 g/cm³ Hinoki Cypressmatch 1.401,010 lbf · 0.42 g/cm³ · Class 21,010 lbf vs 350 · 0.42 vs 0.32 g/cm³ Thermally Modified Western Red Cedarmatch 1.68350 lbf · 0.38 g/cm³ · Class 2350 lbf vs 350 · 0.38 vs 0.32 g/cm³ · modified timber

Computed from measured properties only — hardness, density, movement, stiffness, bending strength and EN 350 class. Price, availability and appearance are never inputs. Figures are representative values, not consignment absolutes: two species within a few percent are equivalent until verified on the material. Full method and the rules the engine cannot break.

Substituting outdoors is a match on durability class and movement first. Colour and grain can be matched later; a wrong durability class shows up as a callback in three monsoons. Where two candidates are close, compare them directly before specifying.

Compare Western Red Cedar side by side

These are the head-to-heads that decide cladding, decking and exterior joinery specifications. Every pairing shows the measured figures side by side; full matrix in the comparison index.

Western Red Cedar vs Thermally Modified Western Red CedarSide-by-side data · 350 lbf Western Red Cedar vs Sugi Japanese CedarSide-by-side data · 320 lbf Western Red Cedar vs Deodar CedarSide-by-side data · 580 lbf Western Red Cedar vs Hinoki CypressSide-by-side data · 1,010 lbf

Calculators relevant to Western Red Cedar

Aimed at exterior detailing in Western Red Cedar: coverage, gaps, coating and durability checks. Full set in the tool index.

Wood Expansion Gap CalculatorJoinery Wind Load Calculator for Timber Structures (IS 875)Construction Wood Acclimation Time CalculatorWood Science Wood Moisture Content TrackerWood Science Timber Post & Column Load CalculatorConstruction Sanding Grit Sequence Planner for WoodConstruction Huber Formula CalculatorMeasurement International 1/4-Inch Log Rule CalculatorMeasurement

Understand the figures

Strength properties — MOR, MOE and what they govern · Durability & fire — EN 350 classes and E84 ratings · Thermal conductivity — k-value and insulation behaviour · ThermoWood species guide — Thermo-D/Thermo-S treatment classes.

Further reading. What is ThermoWood? · Wood moisture content explained · How to calculate board feet.

Common questions about Western Red Cedar

Is Western Red Cedar strong enough for furniture or flooring?

It's a softer timber at 350 lbf (1,557 N), so it dents more easily than oak or teak and isn't the first choice for high-traffic flooring. Where it shines is lighter work — panels, mouldings, interior joinery and anywhere low weight and easy machining matter more than bruise resistance. Match it to the job and it performs nicely.

Can Western Red Cedar be used outdoors without treatment?

Largely yes. It's rated Durable (Class 2) under EN 350, meaning the heartwood naturally resists decay and can handle exterior exposure — decking, cladding, garden furniture — without chemical preservatives. Two caveats worth knowing: the pale sapwood isn't durable, so it should be cut away for outdoor work, and 'durable' isn't 'immortal' — it'll still silver and weather, so a UV oil keeps the colour if you care about looks.

How much does Western Red Cedar move with humidity?

It has moderate movement — radial shrinkage near 2.4%, tangential near 5% (T/R ratio about 2.08). That's typical territory: nothing alarming, but worth planning for. Dry it to the moisture content that suits your service environment, leave expansion room on wide panels, and let it settle in the space for a few days before final fixing and it behaves well.

unverified no published source for this figure · FPL USDA FPL Wood Handbook GTR-190 · WD The Wood Database (Eric Meier) · calc derived from the figures above

Tools that use this species

Janka Database ToolHardness for 60 species Green Weight CalculatorWeight of green timber Shrinkage PredictorDimensional movement EMC CalculatorEquilibrium moisture content Fiber Saturation CalculatorFSP by species Volume Converterm3, CFT, board feet

Sources & references

The Wood Database (Eric Meier) — compiled species data, one of the references behind the panel above. Which figure comes from which reference is not recorded field by field. Spot checks show the numbers do trace to published sources, but not all to the same one: strength values for US species follow the USDA FPL Wood Handbook exactly, while European species draw on European references instead. So a figure that disagrees with any single reference here is not necessarily wrong — different bodies measure specific gravity and shrinkage on different bases. If a number matters to your work, check it against the reference you intend to rely on.
USDA Forest Products Laboratory — softwood tech sheet (Thuja plicata) & Silvics of North America · working properties, durability, uses
North-American forestry references — naturally:wood species data (thujaplicins, machining, finishing) · extractives, working, finishing
EN 350 — European standard for natural durability of wood · durability class

Updated 15 Jul 2026 Values are representative; wood varies with provenance, age and grade. Confirm critical structural or fire figures against a test report for your actual product.