Decking · Western red cedar
How long does a cedar deck last?
Western red cedar sits in the second of the five natural-durability classes the European timber standard uses, a band of 15 to 25 years, and the cedar trade's own decking study models an uncoated deck at 25. There is no warranty bar on this page for an honest reason: cedar decking is sold as graded lumber, and a grade stamp is not a warranty.
Updated
Typical service life: 15–25 years
The 15-to-25-year band is the durability class the American Hardwood Export Council's technical note assigns to western red cedar by name, and it describes how long the heartwood resists decay in the ground — measured on stakes half-buried in soil, not on deck boards. A walking surface sits above the ground and drains, so the band is a floor for the wood's resistance rather than a schedule for a deck. The Western Red Cedar Lumber Association's own decking life-cycle study models an uncoated cedar deck at a 25-year service life, the top of the same band.
Tier 2 · trade / standards literature Range from American Hardwood Export Council — Technical Matters #4: Durability, checked 2026-08-27.
Cedar's durability is a chemistry that leaches slowly, so the variable that matters is how long the board stays wet rather than how cold or hot it gets. A deck in the dry-summer Pacific Northwest interior, open to sun and air on all sides, holds up near the top of the band; the same boards under trees in a humid Southeast summer can be soft at the ends inside a decade. Ground clearance and airflow underneath do more for cedar than any surface treatment.
Why there is no warranty bar here
Cedar decking leaves the mill as graded commodity lumber, and no mill or trade body publishes a homeowner warranty on it. The Western Red Cedar Lumber Association publishes grading rules, installation guidance and a life-cycle study — documents about what the board is and how to hang it, not a term anyone will honour. What durability cedar has is in the heartwood's own extractives, and the sapwood on the same board has none of it, which is why grade matters more here than any paper would.
What shortens it
- Sapwood in the boards — the pale, non-heartwood portion carries none of cedar's decay resistance and is graded, not warranted, out
- Film-forming finishes that crack and then trap water underneath instead of letting the board dry
- Pressure washing, which erodes the soft spring grain and leaves a furred surface that holds dirt and water
- Deep shade and overhanging trees, where moss and constant damp outpace the heartwood's own defences
- Iron fasteners, whose corrosion reacts with cedar's extractives and leaves black staining and softened wood around every screw
Signs of wear to look for
- Silvering to grey is not a symptom — it is the surface weathering normally and says nothing about the wood beneath
- Fuzzy, splintering grain that catches bare feet, especially on boards that have been pressure washed
- Black staining spreading in rings around fasteners
- Soft, crumbly patches at board ends and anywhere the board sits on a joist without drying between rains
- Splits running out from the fastener holes at board ends, widening season by season
Cedar's softness is a surface question; whether the joists, the ledger and the posts below are still doing their job is not — that is an inspection question, not a web-page question.
Other decking materials
- Pressure-treated pine about 15 yrs
- Composite decking (wood-plastic) 8–25 yrs
- PVC decking (cellular PVC) 50+ yrs
- Redwood 10–30 yrs
- Ipe 25+ yrs