October 18, 2026

Western Red Cedar Lumber: Decay Resistance, Grades and Premium Markets

Western red cedar lumber earns its premium in a way few softwoods can: it survives outdoors without chemical treatment, because the defence is built into the wood itself. For sawmillers, dealers and sellers, understanding western red cedar lumber means understanding where that durability comes from, what it does not protect against, how the grades separate clear money from knotty volume, and which markets pay for each. This guide covers the properties, the grading, the handling rules and the selling angles.

For the marketplace view while you read, browse the lumber and forestry equipment marketplace on Lumber Lookup — the mills, edgers and handling gear that produce cedar stock are listed there by category.

What Western Red Cedar Lumber Actually Is

Western red cedar is Thuja plicata, a Pacific Northwest species of the United States and Canada — and, despite the name, not a true cedar. The Wood Database's profile of western red cedar lists trees reaching 165–200 ft tall with trunks 7–13 ft in diameter, which is why long, clear lengths have historically been available from this species. The heartwood is reddish to pinkish brown, often with darker streaks, against a narrow band of pale yellowish-white sapwood. The grain is straight, the texture coarse, and freshly worked wood carries a strong, lingering aromatic scent.

The numbers explain both the appeal and the limits:

Weight: an average dried weight of 23 lb/ft³, per The Wood Database — light enough that handling, freight and installation all get easier.
Hardness: a Janka hardness of 350 lbf, also from The Wood Database. That is soft. Cedar dents and scratches easily, and it will not take traffic or impact the way a hardwood floor or a hardwood deck board does.
Shrinkage: radial 2.4%, tangential 5.0% and volumetric 6.8%, rated low — small movement for a softwood, which is a large part of why cedar siding and trim stay flat and tight in service.
Strength: modest. Cedar is a cladding, trim, shingle and outdoor-joinery wood, not a first-choice structural species where spans and loads govern.

Why the heartwood resists decay

The Wood Database rates western red cedar heartwood as durable to very durable for decay resistance, while noting mixed resistance to insect attack. The durability lives in the heartwood's natural extractives — the same compounds behind the scent — and it is not shared by the sapwood. British Columbia's industry resource Naturally Wood's western red cedar profile makes the same point in production terms: the species produces thujaplicin, a natural defence against rot and fungus, and properly finished cedar products can last for decades even in harsh environments. Two commercial rules follow. First, exterior stock should be all heartwood on the exposed face — sapwood in ground contact or weather exposure is a failure waiting for a season. Second, durability is not invincibility: detailing, drainage and finish still decide service life, a point Naturally Wood also stresses.

Western Red Cedar Lumber Grades: Clear Money, Knotty Volume

Cedar is sold largely on appearance, so the grade ladder is the price ladder.

Clear grades

Clear grades carry few or no knots and are specified where the finest appearance is required. The Western Red Cedar Lumber Association's guidance, published through Real Cedar's trim board grading pages, explains that clear boards have a limited number of natural characteristics and are available kiln-dried or unseasoned, in rough, S1S2E (surfaced one side, two edges) or S4S finishes. Within clears, Clear Heart — heartwood on the exposed face — sits at the top, followed by A Clear and the mixed A-and-Better lots. Vertical-grain clear stock is the most stable and the most uniform, and commands the strongest prices for siding, soffits and architectural trim. Clear stock is also where supply is tightest: it comes from the outer, knot-free wood of large, old logs, so wide, long clears are genuinely scarce.

Knotty grades

Knotty grades — Select Knotty at the top, with Quality Knotty and Architect Knotty patterns also traded — keep sound, tight knots and sell a rustic character rather than a flaw. Real Cedar's grading material notes knotty boards present a more rustic appearance and may be specified seasoned or unseasoned. For fencing, decking, landscape work and knotty siding, Select Tight Knot stock is the workhorse: buyers get the decay resistance and the look, sellers get volume that clear production cannot supply. The grade mistake to avoid is mixing: a pack sold as clear with knotty fall-down in it, or knotty stock photographed to look clear, destroys repeat business in a market built on trust and reorders.

Structural and utility grades

Thicker cedar is also graded structurally under western grading rules for posts, beams and dimension uses. Those grades price on strength and defects, not face appearance. Know which rule book a pack was graded under before you compare two quotes — an appearance grade and a structural grade with the same name are not the same product.

Working, Fastening and Finishing Cedar

Cedar's softness makes it easy to saw, plane, shape and glue, and The Wood Database rates it easy to work with hand and machine tools — with two cautions worth printing on the shop wall. First, the density difference between earlywood and latewood can sand unevenly and dent under careless handling, so protect faces in the yard and on the truck. Second, iron-based fasteners can stain and discolour the wood, especially in the presence of moisture. In practice that means stainless steel or properly coated fasteners for exterior work, a rule Real Cedar's project specifications repeat across siding and trim applications.

Cedar accepts paints, stains and oils well and is notably free of pitch and resin, so finishes do not bleed through the way they can on resinous pines. Unfinished, it weathers to a silver-grey — some buyers want exactly that — but colour retention requires a maintained finish, and sellers should say so plainly rather than let a buyer discover it after the first winter.

Premium Markets That Pay for Cedar

Siding, soffits and trim: the architectural core market, where clear and vertical-grain stock earns its premium on appearance and stability.
Shingles and shakes: the traditional market the species was built on, graded separately and sold on thickness, grain and exposure ratings.
Decking and outdoor living: knotty and clear decking sells on natural durability without treatment-plant chemicals.
Fencing:high-volume knotty business where cedar's light weight cuts installation labour.
Specialty clears: guitar soundboards, boatbuilding, closet lining, sauna and hot-tub work — small volumes, strong prices, exacting buyers.

Compare the softwood selling picture with our guide to Douglas fir lumber, the structural counterpart buyers often weigh against cedar, and with the fast-growing hardwood in our yellow poplar lumber guide — three species, three very different reasons a buyer pays.

A note on pricing honesty: construction-grade cedar is, as The Wood Database puts it, moderately inexpensive, while higher grades of clear, straight-grained lumber can be considerably more expensive. Published per-foot prices move with region, grade and season, so this guide quotes no single figure — check live listings and recent comparable sales before setting a price, and date any range you publish.

Conclusion

Western red cedar lumber sells a rare combination: heartwood that is durable to very durable against decay, low shrinkage, light weight and an appearance ladder from rustic Select Knotty to scarce Clear Heart. Handle it as the soft wood it is, fasten it with stainless, keep sapwood out of exposed faces, and grade honestly — that is how sellers hold the premium this species offers. Ready to trade it? Browse the equipment and lumber marketplace at LumberLookup.com to find the mills and gear behind cedar production, and put your stock in front of buyers who already know what clear cedar is worth.