How long does a fence last: cedar to vinyl

Lifespan by material

There is no honest single number for a cedar fence, or any fence. What the evidence does support is which part of each fence gives out first — and for wood that is almost always the posts, not the boards.

Cedar. The Forest Products Laboratory's Wood Handbook ranks western redcedar heartwood as very resistant to decay — and says untreated sapwood of essentially all species has low resistance. Its own footnote warns that decay resistance may be less in ground contact and in warm, humid climates. That is the case for the mixed build: cedar boards above, treated posts below.

Pressure-treated pine lasts as long as its rating matches where it sits, which the next section covers. Vinyl, composite, aluminum and chain link do not rot, so their lives end at footings, hardware, impact and coatings — vinyl vs wood and chain link vs wood compare them on cost too.

The post decides, and it decides at grade

A wood fence fails at the soil line. Above it the post dries between rains; well below it the soil is stable; in the band either side of grade the wood stays wet. The handbook's threshold is simple — decay can be prevented from starting or progressing if wood is kept below 20% moisture content — and a post at grade rarely is.

That is why the rating on the tag matters more than the species. The American Wood Protection Association's use categories, as summarised in the handbook, put fence pickets and rails in UC3B (above ground, fully exposed) and fence and deck posts in UC4A (general ground contact). UC4B is for ground contact where components are critical or difficult to replace, or the decay hazard is high.

What kills a fence first

1. 01The wrong post rating. An above-ground board or post in soil. YellaWood lists fence posts as a ground-contact use and excludes above-ground stock used in contact with the ground.
2. 02A collar that holds water. A dished or flush concrete top pools water against the timber, and a post end bedded in a concrete cup cannot drain. Crown it and put gravel under the end.
3. 03Sprinklers. The same warranty excludes above-ground wood wetted on a frequent or recurrent basis by watering systems. A sprinkler that hits the fence every night is a ground-contact exposure.
4. 04Soil, mulch and leaf litter against the boards. Excluded too: wood where soil, vegetation or debris may build up against it, and above-ground wood installed less than six inches above final grade on permeable supports.
5. 05Cut ends. A fresh cut exposes wood the treatment may not have reached. YellaWood will not warrant posts or boards cut, bored or routed after treatment, and requires an end-coat preservative on cuts in Douglas-fir and hem-fir.
6. 06Weathering. The handbook notes that weathering can be as much a factor in the long-term life of decks and fences as decay — checking, splitting and warping, which a finish that slows moisture movement helps keep down.

The collar detail is drawn out step by step in how deep fence posts should be, and the bag count for a properly sized hole is the post concrete calculator.

Making it last longer

At build time, which is where most of the life is decided: ground-contact posts, gravel under each post, a crowned collar, boards held clear of the soil, every cut end sealed, and hot-dip galvanized or stainless fasteners. The handbook singles out end grain on fences and railings — seal it during construction, or a film finish traps the water it lets in.

Every year: pull soil, mulch and leaves back from the bottom of the boards, aim the sprinklers away, and push a screwdriver into each post at grade. Gate posts first — they carry the most load, and the gate hardware on them stays square only while the post does.

On its own schedule: a penetrating finish slows the wetting and drying that checks and splits boards. For saw-textured cedar siding — the closest row in the handbook's table to a fence picket — its estimate for a semi-transparent stain is 4–8 years. Size the job with the fence stain calculator, and see stain vs paint before you reach for a solid colour.

Repair or replace

Repair when the posts are sound and the trouble is above them: a split picket, a loose rail, a sagging gate, a worn finish. Boards and rails are cheap and replaceable one at a time. One soft or leaning post on an otherwise sound line is a post replacement, not a fence replacement.

Replace when the posts are going as a group — several soft at grade, the line leaning in one direction, collars heaving — because every new board you hang is then hung on a structure that still has to come out. Price the rebuild with the fence cost calculator, and compare it with the life you would get from each material before you choose. The same frame-versus-surface logic runs through how long a deck lasts.