A well-built cedar fence in Portland lasts about 15–25 years. The catch most homeowners learn the hard way: the posts almost always fail first, rotting at the soil line while the pickets above are still solid. So "how long does a cedar fence last" really has two answers — the above-ground wood can go 20–30 years, but the part buried in our wet PNW soil is the weak link. Below are the realistic ranges by component, treated vs. untreated, what shortens cedar life here, and the specific things that push you toward the long end.
Cedar fence lifespan, by component
A fence isn't one thing — it's posts in the ground, rails spanning between them, and pickets on the face. Each part weathers differently, so a single "lifespan" number hides what's actually going on. Here's how long each piece lasts in the Portland metro:
| Component | Typical lifespan (Portland) | Why |
|---|---|---|
| Whole fence (overall) | 15–25 years | Limited by whichever part fails first — usually the posts |
| Posts — untreated cedar in soil | 8–15 years | Constant ground moisture; rot starts right at the soil line |
| Posts — treated or concrete-set w/ drainage | 20–30+ years | Kept off wet soil; water drains away instead of pooling |
| Pickets / boards | 20–30 years | Above ground, dry out between rains |
| Rails (stringers) | 15–25 years | Horizontal, so they hold water on top edges and joints |
Read it top to bottom and the pattern is clear: the pickets you actually look at are rarely the problem. It's the posts and rails — the parts touching soil or holding water — that decide when the whole fence comes down.
How long do cedar fence posts last?
This is the number that matters most. Untreated cedar posts set directly in dirt typically last 8–15 years in Portland — the rot begins at the soil line, where wood, water, and oxygen all meet. By the time you can wiggle a post, the buried section is usually punky even if the visible wood looks fine.
Set those same posts up to survive our climate — pressure-treated posts, or cedar posts on a gravel drainage base with a sloped concrete collar — and you're looking at 20–30+ years. That's why many Portland builds pair cedar pickets (for the look) with treated posts (for the lifespan). It's also why two cedar fences that look identical on day one can fail a decade apart.
How long will an untreated cedar fence last?
Western Red Cedar contains natural oils (thujaplicins) that resist rot and insects, so it performs far better untreated than untreated pine would. A fully untreated cedar fence in the Pacific Northwest generally lasts 12–20 years — shorter if the posts touch soil or sit in standing water, longer if it stays off the ground and gets an occasional stain.
What untreated cedar doesn't get you is buried-post longevity. The natural oils slow surface rot, but no amount of native rot resistance beats constant saturation in clay that holds water all winter. If you go untreated for the look, the smart move is to still protect the posts — gravel base, drainage, and keeping wood off soil — rather than relying on the cedar alone.
Treated vs. untreated cedar — what actually changes
"Treated cedar" usually means one of two things: pressure-treated lumber (often the posts) or a surface stain/sealer. They do different jobs:
| Untreated cedar | Stained cedar | Pressure-treated posts | |
|---|---|---|---|
| Above-ground lifespan | 15–20 yrs | 20–30 yrs | n/a (used for posts) |
| In-ground lifespan | 8–15 yrs | 10–15 yrs | 20–30+ yrs |
| Look | Ages to silver-grey | Holds tone, your choice of color | Greenish; usually hidden below grade |
| Upkeep | None required | Re-stain every 3–5 yrs | None |
| Best use | Low-budget, low-fuss | Maximize cedar's life and looks | The part in the ground |
The takeaway most Portland homeowners land on: stain the visible cedar to protect the pickets and rails, and use treated (or properly drained) posts to protect the part you can't see. For the deeper material comparison, see cedar vs. pressure-treated.
What shortens cedar fence life in the wet PNW
Portland's climate is hard on wood for one reason: persistent moisture. Roughly 36+ inches of rain a year, dense clay that holds water, and mild winters that keep things damp instead of frozen. Here's what actually kills cedar fences early:
Ground contact
Any cedar touching soil wicks moisture and rots from the bottom up. Pickets that run all the way to the dirt, rails resting on the ground, posts buried without a drainage base — all of it shortens the fence's life by years.
Standing water and poor drainage
Post holes that fill with water and don't drain turn into little rot tanks. Clay soil makes this worse because water has nowhere to go. A post sitting in a saturated hole all winter can fail in under a decade no matter how good the wood is.
No finish on a sun-and-rain face
Bare cedar greys out and develops surface checks (cracks) as it swells and shrinks with each wet-dry cycle. Those checks let water deeper into the wood. Untreated cedar survives this — it just ages faster than stained cedar does.
Trapped moisture and debris
Dirt piled against the fence, sprinklers hitting it daily, dense shrubs that hold the wood damp, or leaf litter packed in the corners all keep cedar wet long after the rain stops. Cedar lasts longest when it can dry out between soakings.
If a cedar fence is failing at 8–10 years, look at the posts before blaming the wood. In Portland, premature failure is almost always a drainage problem — posts set in dirt or in water-filled holes — not bad cedar. Replacing pickets on rotted posts is throwing good money after bad; the fix is at the soil line.
How to make a cedar fence last longer
You can't change Portland's rain, but you can change how the fence handles it. These are the moves that reliably push a cedar fence toward (and past) the 25-year end:
- Gravel base + concrete collar on every post. A few inches of gravel at the bottom of the hole lets water drain away from the post; a concrete collar sloped to shed water keeps the soil line dry. This single detail is the biggest factor in post lifespan.
- Keep wood off the soil. A 2-inch gap between the bottom of the pickets and the ground (or a treated kickboard at the base) stops the wicking that rots fences from the bottom.
- Use treated posts. Cedar pickets with pressure-treated posts is the standard PNW combo — you get the cedar look and the post longevity.
- Stain it every 3–5 years. A penetrating, semi-transparent stain with UV blockers slows greying and checking and keeps the pickets and rails sound. See our guide to staining fences in Portland for timing and product types.
- Improve drainage and airflow. Pull soil and mulch back from the base, redirect sprinklers, and trim shrubs so the fence can dry between rains.
- Use the right cedar. Western Red Cedar — the PNW standard — has the best natural rot resistance for fencing; cheaper "cedar" species and sapwood-heavy boards rot faster.
Western Red vs. other cedar
Not all "cedar" is equal. Western Red Cedar is what almost every Portland fence is built from, and for good reason — it's locally milled, dimensionally stable, and rich in the natural oils that fight rot. Its heartwood (the darker inner wood) is the most rot-resistant part; boards heavy on the lighter sapwood weather faster.
Other species sold as "cedar" — Eastern White Cedar, or imported alternatives — are often softer, less rot-resistant, or simply harder to source here. For a fence that has to survive PNW winters, Western Red Cedar heartwood is the benchmark. If a quote just says "cedar," it's worth asking which species and grade you're getting.
Is cedar worth it over the long run?
For most Portland yards, yes — a 15–25 year lifespan at cedar's price point is a strong value, and it ages into the natural silver-grey a lot of homeowners actually prefer. The fences that disappoint are almost always the ones that skipped the drainage and post details, not the ones that chose cedar. If you're weighing the upfront numbers, our Portland fence cost guide breaks down per-foot pricing by material.
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