Cedar vs Pressure-Treated Fence

“Cedar lasts 30 years, pine lasts 15” is on every contractor blog, and it is true — of the boards. It quietly compares a species (cedar) with a treatment (pressure-treated pine), and those are different kinds of protection that behave differently depending on where the wood is.

Above ground, what kills a fence board is sun, water cycling, and movement. Cedar's tight grain and natural oils make it dimensionally stable, so it stays where it was nailed and greys gracefully. Treated pine is sold wet from the treatment process and dries on your fence — shrinking, twisting, and checking as it goes. That is why a treated fence installed tight has gaps by the second summer.

Below ground, the problem is rot, and the answer flips. A ground-contact treated post is engineered to sit in wet soil for decades. Cedar's resistance lives in its heartwood and is not equivalent to a ground-contact rating — a cedar post commonly rots through at grade in 10–20 years, right when the cedar boards above it are hitting their stride. Since a fence fails at its posts→, choosing cedar everywhere buys the shorter-lived fence at the higher price.

Per-foot pricing by species is on the wood fence cost page→; this page keeps cedar as a premium because the premium is the decision.

Cedar runs about 25–50% more than treated pine for the same fence, and the spread is regional to a degree most comparisons ignore. In the Pacific Northwest and much of Texas, cedar is the local wood and the premium can be under 20%. In the Midwest and Southeast, pine is milled down the road and cedar is trucked in; the premium there can approach double. Labour is the same either way, which is why the gap shrinks on installed price and widens on materials.

For that money you get, in order of how much it matters: boards that stay flat, a fence that does not need immediate finishing to look acceptable, roughly 5–10 more years of board life, and a colour most people prefer. What you do not get is a longer-lived fence overall — unless the posts are treated.

Where the premium is worth it

• A privacy fence you will look at every day from the house
• Anywhere you intend to leave the wood unfinished and let it grey
• Horizontal designs, where board flatness is the whole look — see horizontal fences→
• Regions where cedar is local and the premium is small

Where treated pine is the better buy

• Any fence you plan to paint or solid-stain — the colour hides the species
• Back and side boundaries nobody looks at closely
• Budgets where the cedar premium would otherwise come out of post depth or gate hardware
• Short-horizon ownership, where 10–20 years is plenty

Most experienced crews will build this without being asked; the point of knowing about it is so that you can check the quote for it.

• Posts: pressure-treated, UC4A minimum (ground contact), UC4B where the soil stays wet. 4×4 for fences to 6 ft; 6×6 or steel for 8 ft, gates, and corners.
• Rails: either. Treated rails are cheaper and hidden; cedar rails are lighter and match. Rails do not touch the ground, so rot is not the issue — sag is, and that is a span question.
• Boards: cedar, with the heartwood face out where you can choose. Ask which cedar — Western red and northern white are the common fence species; incense and Port Orford turn up regionally.
• Fasteners: hot-dip galvanized or stainless throughout. Not electro-galvanized, not bright.
• Base: keep cedar boards an inch or two off the soil, or run a treated kickboard along the bottom to take the splash.

A quote that says “cedar fence” and nothing about the posts is worth one question. If the posts are cedar, you are paying the premium in the one place it works against you.

This is the detail most likely to be wrong on a cheap fence and invisible for two years. Modern treatments — ACQ and copper azole replaced arsenic-based CCA — are copper-rich and corrosive to ordinary steel. Plain or electro-galvanized nails in treated wood rust at the shank, and the board loosens. Cedar has the mirror problem: its tannins react with plain steel and bleed black streaks down the face of the board from every nail head.

The answer is the same for both: hot-dip galvanized or stainless steel. It costs a little more per box and nothing per foot that you will notice. Ask for it by name, and if the crew is using a nail gun, ask what is in the coil.

Cedar does not need a finish to survive — the oils that resist rot are in the wood whether or not you stain it. A finish on cedar is for colour: unfinished, it goes silver in a year or two, evenly, and many people prefer it. Treated pine benefits more from a finish, because treatment protects against rot and insects but not against the sun and water cycling that cause checking — and it cannot be finished until it has dried, which is two to six months after installation. Stain it wet and the finish peels.

The full decision — stain, seal, paint, or leave it — is in should you stain your fence?→

If the goal is a fence that never needs a finish and never warps, the honest comparison is not cedar against pine — it is wood against vinyl→ or composite→, both of which cost more up front and nothing in refinishing. And if posts are the worry, steel posts under wood boards remove the rot question entirely for a modest premium — see post materials→.