The short answer
If the post is sound but its footing has moved, dig around it, straighten it and re-set it in fresh concrete. If the timber has rotted at ground level but is solid above, bolt a concrete repair spur alongside it. If the post is rotten or snapped, replace it – ideally with a concrete post. Fix it quickly, because a leaning post puts strain on its neighbours.
Fence posts lean for a few reasons: the timber has rotted at ground level, the post was not set deep enough, the soil is soft or has been disturbed, or wind and a heavy panel have gradually levered it over. Whatever the cause, a leaning post pulls on the panels either side and can bring a whole section down in the next storm.
Before deciding on a repair, push the post and look closely at the base.
Diagnose the problem
Push a screwdriver into the timber just below ground level. If it sinks in easily, the post has rotted and straightening it will not last.
- Does the whole post and concrete rock together? The footing has moved – the post may be re-settable
- Is the timber soft or crumbling at ground level? The post has rotted
- Has the post snapped? It needs replacing
- Are several posts leaning? The whole fence may be near the end of its life
Three ways to fix it
Re-setting: remove the panels either side, dig around the post, break away the old concrete if needed, straighten the post and set it again in fresh concrete or post mix. This works when the post itself is sound.
Repair spur: a short concrete post is set in the ground beside the existing post and bolted to it. The spur takes the load, so a post that has rotted only at ground level can carry on for years. It is quick and much cheaper than replacing the post.
Replacing the post: if the post is badly rotted or broken, take it out and fit a new one. Swapping to a slotted concrete post prevents the same problem returning.
Temporary support
If you cannot fix it straight away, prop the fence with a timber brace screwed to the post and staked into the ground on the leaning side, and remove any trellis or climbers adding weight. Do not leave it too long – a strong wind can take the whole section.