A leaning fence post never gets better on its own. It starts with a slight tilt, then the panel next to it starts to twist, and one windy night the whole bay goes over and takes the next one with it.
The good news is that one bad post doesn't mean a new fence. But you do need to fix the right thing. Before you buy anything, work out why the post has moved, because the fix for a rotten timber post is completely different from the fix for a concrete post that's tipped over in its footing.
Why is the post leaning?
Have a proper look. Push the post at the top and watch the bottom. Dig back a little soil around the base if you need to.
The timber has rotted at ground level
This is the most common one with wooden posts. The bit just above and below the soil stays damp, and over the years it goes soft. Push a screwdriver into the post at ground level. If it sinks in easily, the post is rotten and it's only the panels holding it up.
The post and its footing are moving together
If the post itself is solid but the whole lump of concrete around it rocks in the ground, the footing has failed. That's usually because the hole was too shallow or too narrow, the ground is soft clay that's moved, or there was barely any concrete in there in the first place.
The post has snapped or cracked
Timber posts can snap at the base, often where they've rotted. Concrete posts can crack, usually after a hard knock or a storm, and once the steel inside starts to show, that post is finished.
Something is pushing it
Tree roots, a heavy shrub growing through the fence, soil piled up against one side, or a neighbour's shed leaning on it. Fix the post without sorting the cause and you'll be doing it again next year.
Safety before you start
- Check for cables and pipes before you dig. Fence lines often have services running near them. Use a cable detector, and if you're not sure what's down there, find out first. Linesearch BeforeUDig is a free service for checking buried utilities.
- Take the panels out first if the post is leaning badly. A loose panel can drop or swing when you start working on the post.
- Concrete posts are heavy. Don't lift one on your own, and lift with your legs, not your back.
- Wear gloves and eye protection when you're breaking out old concrete.
Fixing a timber post
Option 1: a repair spur
A repair spur is a short concrete or steel post that you set in the ground next to the old post and bolt to it. It's a quick fix when the timber has rotted at the base but the post above ground is still sound.
It works, but it's not pretty, and the old post will keep rotting where it meets the ground. I see it as a way of getting a few more years out of a fence that's due for replacing anyway. If the rest of the fence is in good shape, I'd sooner replace the post. We stock concrete repair spurs in 3x3 and 4x4 sizes, and FENCEMATE steel repair spurs in 1.0m and 1.2m lengths.
Option 2: replace the post
This is the proper fix, and it's not as bad as it sounds.
- Take out the panels either side. If they're nailed or screwed to the post, remove the fixings carefully so you can reuse them.
- Dig out the old post and its concrete. Dig around the footing rather than trying to snap it out. Rocking the post back and forth as you dig helps loosen it. A big footing might need breaking up with a breaker bar or a hired breaker.
- Clean out the hole so it's the right depth and width for the new post. For most garden fences that's around 600mm deep.
- Set the new post using a string line from the posts either side, so it sits in line and at the right height. Check it's upright on two faces with a spirit level.
- Fill with post mix, add water and hold the post plumb while it goes off.
- Refit the panels once the post has set.
There's more in our guide on how deep to dig post holes.
Should you go back with timber?
You don't have to. If you're replacing a post anyway, you can put in a concrete post or a galvanised steel one instead. Bear in mind a slotted concrete post holds the panel in a groove, so it needs to suit the panels you've got, and it has to be in line with the posts either side. Our fence post buyers guide goes through the options.
Fixing a concrete post
Concrete posts don't rot, so when they go wrong it's usually the footing or a crack.
A concrete post leaning in its footing
If the post is undamaged but the footing has moved, you have two choices. You can dig out the whole lot and reset the post properly with fresh post mix. Or, if the post is fine but the old concrete has broken up, dig it out and reset the post in a bigger, deeper hole.
Either way the panels have to come out first. Slotted concrete posts hold the panels in the groove, so you can't straighten one with the panels still in.
A cracked or snapped concrete post
Once a concrete post has cracked through, it has to be replaced. There's no sensible repair. Take out the panels and the gravel board, dig out the old post and footing, and set a new one in the same spot.
Measure the old post before you order. Slotted concrete posts come in different heights. For a 6ft panel on a gravel board you need a 9ft post, with 2ft in the ground. If the panel sits on the ground with no gravel board, it's an 8ft post. On a slope, go one size longer. You can see our range on the concrete fence posts page, from £25.99 for a 9ft slotted post. If your gravel board took a hit as well, our concrete gravel boards slot straight in, and the gravel board buyers guide explains the sizes.
A lighter option: DuraPost
If lifting concrete posts isn't for you, DuraPost galvanised steel posts are worth a look. They're much lighter to handle, they don't rot, and they're slim enough to look tidy. You set them in post mix in the same way. Our DuraPost buyers guide explains how they fit with different panels.
Common mistakes I see
Packing it with soil. Kicking soil back round a post and stamping on it won't hold a 6ft fence in the wind.
Too little concrete. A post sitting in a shallow scoop of concrete will rock loose. Dig the hole to the proper depth.
Not checking the neighbours. If one post has rotted, the others were probably put in at the same time. Push every post on the run before you decide it's a one-post job.
Straightening a post with the panels still in. You'll crack the panel or the post. Take them out.
Concrete up to the top of the hole on timber posts. Finish the concrete just above ground level and slope it away from the post, so water runs off rather than sitting against the timber.
When to get help
Replacing one post is a good DIY job if you're reasonably fit and have a helper. I'd get someone in when:
- Several posts have gone and you're really looking at a new fence.
- The old footings are huge and you'd be breaking out a lot of concrete.
- The fence is on a slope, next to a retaining wall, or the ground is very hard.
- You can't find out what services are under the fence line.
Our fencing installation service can take it off your hands.
Get the right post first time
Send us a photo of the post and the panel on WhatsApp, and tell us the height of the fence. We'll tell you what you need, whether that's a new post, post mix, a gravel board or a few new panels to go with it. You can ring Northfleet on 01322 787312 or South London on 020 8698 4064, or order online 24/7. Check our delivery prices for your postcode, or find your nearest depot on our store locator.
Fencers and landscapers can open a free trade account for trade prices and faster collection.
FAQs
Can you straighten a leaning fence post without removing it? Sometimes, if it's a timber post and only the soil around it has moved, but it rarely lasts. For a proper fix, take the panels out, dig out the old footing and reset the post in post mix. A rotten or cracked post needs replacing.
Can a broken concrete fence post be repaired? Not really. Once a concrete post has cracked through it needs replacing. Take out the panels and gravel board, dig out the old post and footing, and set a new post of the same height.
What size post do I need for a 6ft fence? A 9ft post if the panel sits on a gravel board, or 8ft if it doesn't. Either way, 2ft goes in the ground.
