Cedar Decking
Western Red Cedar (Thuja plicata) is a premium natural decking choice valued for its natural decay resistance, dimensional stability, and warm appearance. The go-to natural wood deck board for contractors and homeowners seeking a traditional aesthetic.
Fast Facts
- What Is It?
- Western Red Cedar or Northern White Cedar dimensional boards used for deck surfaces, siding, and exterior trim.
- Common Uses
- Deck boards, deck railings, pergolas, outdoor furniture, siding, exterior trim.
- Cost Range
- $2.50–$6.00 per linear foot for 5/4×6 depending on grade and region.
- Durability
- 15–25 years above grade with proper finishing. Naturally resistant to rot and insects without chemical treatment.
Specifications
| Property | Value |
|---|---|
| Species | Western Red Cedar (Thuja plicata) or Northern White Cedar |
| Grading Standard | NLGA / WCLIB — Select, #1 Clear, #2 Clear, Knotty grades |
| Common Deck Profile | 5/4×6 (1.0″ × 5.5″ actual), 2×6 (1.5″ × 5.5″ actual) |
| Janka Hardness | 350 lbf (WRC) — soft; use appropriate spacing and fastening |
| Moisture Content | S-DRY ≤ 19%, KDAT ≤ 15% target |
| Fastener Recommendation | Stainless steel or hot-dipped galvanized; hidden clip systems preferred |
Why Contractors Choose Cedar for Deck Boards
Western Red Cedar's natural oils — including thujaplicins — make it inherently resistant to decay, rot, and insect attack without chemical treatment. Its straight grain, dimensional stability, and workability (it machines, sands, and finishes cleanly) have made it the preferred premium deck board species in North America for generations.
Grades and What They Mean
Cedar deck boards are graded by knot frequency and size, grain orientation, and surface consistency. Clear grades (#1 and #2 Clear) are virtually knot-free and show tight, parallel grain — ideal for premium installs. Tight Knot (TK) and Knotty grades contain sound, fixed knots and are the workhorse choice for contractor-grade decks at a lower price point. All grades share the same natural durability.
Installation Tips
Acclimate cedar to local humidity before installation to minimize post-install movement. Leave 1/8″ spacing between boards for drainage and airflow. Use stainless steel or hot-dipped galvanized fasteners — reactive fasteners will cause tannin staining. Pre-drill near board ends to prevent splitting.
Frequently Asked Questions
Does cedar need to be sealed or stained?
Cedar is naturally decay resistant but will weather to a silvery gray if left untreated. Apply a water-repellent preservative or penetrating oil stain within 4–8 weeks of installation and every 2–3 years thereafter to maintain color, prevent checking, and maximize service life. Transparent and semi-transparent penetrating stains outperform film-forming products on cedar.
How does cedar compare to pressure-treated lumber for decking?
Cedar offers a more attractive natural appearance, lighter weight, and natural rot resistance without chemical treatment — making it easier to work and safer to handle bare-handed. PT lumber is significantly less expensive, stronger structurally, and better suited for framing and ground-contact applications. Many contractors use PT for the framing and cedar for the visible deck boards.
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Comparisons Featuring This Material
Also Consider
Pressure-Treated Lumber
Pressure-treated lumber is dimensional softwood (typically Southern Yellow Pine) infused with preservative chemicals under pressure to resist rot, decay, and insect damage. The most common decking and structural lumber for outdoor applications.
Composite Decking
Composite decking combines wood fiber and recycled plastic (PVC or polyethylene) into a board that mimics the look of natural wood with dramatically lower maintenance requirements. The fastest-growing segment of the decking market, with top brands including Trex, TimberTech, and Fiberon.
Ipe Decking
Ipe (Handroanthus spp., formerly Tabebuia) is an extremely dense Brazilian hardwood prized for exceptional durability, fire resistance, and a rich dark-brown appearance. Often called "ironwood," it's the premium choice for high-end residential and commercial decks.
Cedar Siding
Cedar siding is a premium natural wood cladding valued for appearance, dimensional stability, and natural extractives that help resist decay when properly detailed and maintained.