How Long Does Cedar Fencing, Decking & Siding Actually Last?

Type "how long does a cedar fence last" into Google and you'll get answers anywhere from 15 to 40 years — which isn't wrong, exactly, it's just useless without knowing why the number moves that much. The real answer depends on three things: what you built (fence, deck, or siding), which species you built it with, and whether anyone ever gets around to maintaining it. Here's the honest breakdown, not a single made-up average.

The Short Answer

Those ranges assume Western Red Cedar, BC's coastal climate, and standard construction-grade lumber that isn't sitting directly on soil. Species and grade can shift the numbers meaningfully in either direction — more on that below.

Why Decking Wears Out First

Decking takes the most abuse of the three: foot traffic, standing water, direct UV from above, and — depending on the household — furniture legs, planters, and the occasional dog. Horizontal surfaces also hold water the longest, since rain has nowhere to run off quickly the way it does on a vertical fence face or siding board. That combination of wear and moisture is why decking is realistically the first of the three to need board replacement, well before the substructure underneath it fails.

Why Fencing Falls in the Middle

A fence sees less foot traffic and less standing water than a deck, but it's fully exposed to weather on both faces, and — critically — the posts sit partially in the ground, which is the single biggest factor in how long a fence actually lasts. Fences essentially never fail from the boards rotting first; they fail from the posts going soft at the ground line. That's also why post material matters more than board material if you're trying to extend a fence's life.

Why Siding Lasts Longest

Siding is mounted vertically, usually with some roof overhang protecting the top courses, and it never sits in standing water or contacts soil the way a fence post or deck substructure does. That's the whole reason well-built cedar siding routinely outlasts fencing and decking on the same property by 10–15 years — it's simply exposed to less of what actually degrades wood.

Species Changes the Math

Western Red Cedar is the benchmark for rot and insect resistance, but it's not the only option, and it's not always the longest-lasting one. In our comparison of Western Red Cedar, Yellow Cedar and Sugi, Yellow Cedar comes out denser and even more rot-resistant than WRC — which matters most exactly where lumber is weakest: fence posts and deck substructure sitting near or in the ground.

The upgrade isn't expensive relative to what it buys you. A Western Red Cedar 4x4x8' post runs $21.00 at our yard; a Yellow Cedar 4x4x8' post is $25.20 — about $4.20 more per post. On a 50-foot fence built in 8-foot sections (7 posts), that's roughly $29 total to put the most failure-prone part of the fence on the more rot-resistant species. It's a small line item next to a fence that's supposed to last decades.

What Actually Kills Cedar Early

• Ground contact. Fence boards, post bottoms, or deck ledgers sitting directly against soil rot years before the rest of the structure — keep boards 1–2" off grade and set posts in concrete, not just backfilled dirt.
• Skipped maintenance. The gap between our "unmaintained" and "maintained" columns above isn't marketing — it's the difference between a wash-and-reseal cycle every 2–5 years and letting a failed finish stay failed. Our cedar maintenance guide covers the actual schedule.
• Wrong fasteners. Standard steel screws and nails corrode and streak in wet cedar; stainless or hot-dipped galvanized fasteners cost a little more and last as long as the wood.
• Standing water on horizontal surfaces. Deck boards and top rails that pool water instead of shedding it check and cup years ahead of schedule — proper spacing and slight pitch matter as much as the wood species.

Does Grade Affect Lifespan?

Less than people assume. Grade (Clear, Select Tight Knot, or standard/knotty) is mostly about appearance and knot count, not rot resistance — a knotty fence board and a clear one from the same species hold up to weather about the same. We cover the grading question in full in Cedar Grades Explained: Clear vs. #2 vs. Select Tight Knot.

Realistic Lifespan, Species by Species

All three ranges assume basic maintenance and no ground contact. The wide spread within each row is mostly down to maintenance, not luck.

Shop by Application

• Fencing lumber
• Decking boards
• Siding & trim

Frequently Asked Questions

How long does an untreated cedar fence last in BC?

Roughly 15–20 years left completely unmaintained, and 25–30+ years with a basic clean-and-reseal cycle every few years. Posts, not boards, are usually what fails first.

Does cedar decking last as long as cedar fencing?

No — decking typically has the shortest lifespan of the three main applications, usually 10–15 years unmaintained, because it takes the most foot traffic, standing water and direct UV exposure.

Does species matter for how long cedar lasts?

Yes. Yellow Cedar is denser and more rot-resistant than Western Red Cedar, which matters most for parts near or in the ground, like fence posts and deck substructure.

Does a higher lumber grade mean it lasts longer?

Not really — grade is mostly about knot count and appearance, not weather resistance. A knotty board and a clear board of the same species hold up to rot and UV about the same.

Prices current as of publication and subject to change with lumber market conditions. Confirm current pricing and stock before ordering.