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Fix a rotten fence post

We'll brace safely, remove rot at the soil line, set a new post on a proper footing, and reattach the fence—or tell you when utilities or heavy construction need a contractor.

Troubleshooting · Home maintenance
3–8 hours (plus concrete cure)
What you'll need
  • New pressure-treated post (match size)
  • Shovel, pry bar, reciprocating saw (optional)
  • Stakes, 2x4 braces, exterior screws
  • Bagged concrete mix, water, wheelbarrow (if pouring)
  • Level
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Steps

Goal: Confirm rot, keep the fence standing while you work, remove the failed post, and set a durable replacement.

Brace and strip

Goal: Support the fence and free the rotten post without collapse.

  • Stake-brace both sides. Remove rails and pickets from the post. Label parts if reusing.

When to get help

Call a contractor if you uncover unexpected utilities, cannot get a plumb post in the hole, or the fence is a shared boundary requiring permits.

For leaning without rot, see Fix a leaning fence.

Verification

  • New post is plumb and matches neighbor post height at the top rail.
  • Concrete is cured before heavy gates or tension wire load that post.
  • Soil drains away from the post base after typical rain.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm rot Probe at soil line; mark post.
  2. Brace and strip Brace panels; detach rails from post.
  3. Remove and re-set Dig out old post; set new post plumb.
  4. Concrete and rehang Pour or compact; reattach rails and gate.
  5. Contractor Utilities, rock, or heavy panels.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Post size and spacing
  • Rot depth and whether rails were affected
  • Hole depth and footing type
  • Concrete batch and cure wait
  • Steps already tried

Is the post soft or rotten at the soil line?

Probe with a screwdriver—crumbly fibers mean replacement.

Rotten: brace and replace. Sound: you may only need alignment from Fix a leaning fence.

Yes No

You can change your answer later.

Post is sound

If the wood is firm, see Fix a leaning fence for plumb and footing issues without full replacement.

Done

Brace, remove, and replace the post

Stabilize the span, dig out the old post, set new treated wood, pour concrete.

Brace panels, detach rails, remove rot, set a new post plumb, pour concrete, then reattach when cured. Good: fence is rigid and plumb. Bad: utilities or rock—call a contractor.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why do fence posts rot?
Wood stays wet where it enters the soil—splash, irrigation, and capillary wicking. Non–pressure-treated wood, shallow concrete that holds water against the wood, and poor drainage accelerate rot.
Can I repair a rotten post without replacing it?
Epoxy or partial wraps rarely last in ground contact. For structural safety, remove the rotten section and set a new pressure-treated post on a proper footing. Short-term bracing is only to keep the fence safe until replacement.
When should I call a pro for a rotten post?
Call a contractor if you must dig near utilities, the fence is tall or tied to masonry, or neighbors share the boundary and need coordinated repair.

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