Why Fence Posts Always Rot at Ground Level

Look at any failed timber fence and the damage is in a band a few inches either side of the soil line. There is a reason, and it points at the fix.

The wet-dry cycle

Wood fully buried stays saturated and rots slowly. Wood in open air stays dry and lasts. The band at ground level does both repeatedly, and that cycling is what breaks the fibres down.

Add the fungi and insects that live in that top few inches of soil and you have the perfect conditions for failure in one narrow band.

What makes it worse in Torrance

Sprinklers. A head throwing onto the base of a fence keeps that band permanently damp through months when it should be drying out.

Mulch and soil banked against the boards do the same thing. Both are easy to fix and both add years.

Concrete is not automatically the answer

A post set in concrete with no drainage sits in a bucket of water after rain. The concrete holds the moisture against the timber rather than keeping it out.

Gravel at the base of the hole, so water can escape downward, matters as much as the concrete around it.

Steel posts

A galvanised steel post inside a timber cover removes the failure point entirely, because there is no wood in contact with soil.

It costs more up front. On a long run, or anywhere irrigation reaches the fence line, it is usually the cheaper decision over twenty years.

Catching it early

Push each post firmly at chest height once a year. Any give means the section below ground has gone, whatever the visible timber looks like.

One post replaced early is a morning. Three posts replaced late is a new fence.