Published · By Frank DeLozier, Owner & Master Fence Builder
A post set plumb, braced, and locked in a concrete collar, the difference between a fence that lasts and one that leans.
To set a fence post that won’t lean, dig a hole about three times the post’s width and roughly a third of its height deep, add gravel for drainage, plumb the post and brace it, then fill with concrete and slope the top to shed water. In Oklahoma, depth and concrete are what beat the wind.
How to Set a Fence Post in Concrete
Tools
- Post hole digger or power auger
- Level or post level
- Tape measure
- Wheelbarrow (for mixed concrete)
- Temporary braces and stakes
Materials
- Fence post (wood or steel)
- Gravel
- Concrete mix (fast-set or standard)
- Water
- 1
Dig the hole
Dig about three times the width of the post and roughly a third of its above-ground height deep. In Oklahoma we go to the proper depth so wind cannot lever the post out.
- 2
Add a gravel base
Put a few inches of gravel in the bottom of the hole so water drains away from the post base instead of pooling against it, which is where wood rots first.
- 3
Set and plumb the post
Place the post on the gravel and use a level on two adjacent sides to get it truly plumb. A post level that wraps the corner makes this easier.
- 4
Brace the post
Attach temporary braces to two sides and stake them to the ground so the post cannot drift out of plumb while the concrete sets. This is the step DIYers most often skip.
- 5
Pour the concrete
Add concrete around the post, either dry fast-set mix topped with water, or wet-mixed concrete, filling the hole and working out air pockets. Recheck plumb as you go.
- 6
Slope the top to shed water
Mound and slope the top of the concrete slightly away from the post so rainwater runs off instead of sitting against the wood.
- 7
Let it cure before building
Leave the braces on and let the concrete cure per the bag’s directions before hanging rails, pickets, or a gate. Give gate posts extra time before hanging a heavy gate.
Why Fence Posts Lean in the First Place
A leaning post is almost always a footing problem. The usual causes are a hole that was too shallow, a post set without concrete, no bracing while the concrete cured, or water and expansive clay soil working the post loose over the seasons. In Oklahoma, wind then finishes the job.
The good news is that every one of those causes is preventable at install. Get the depth, the concrete, the bracing, and the drainage right, and the post has no reason to lean. That is the entire goal of setting a post well.
How Deep and Wide Should the Hole Be?
Two rules of thumb cover it: bury about a third of the post’s total length, and dig the hole about three times the width of the post. For a 6-foot fence that means a hole in the 24- to 36-inch range and roughly a foot across for a standard 4x4 post.
Depth resists wind by giving the post leverage against being pushed over, and width gives room for a solid concrete collar rather than a thin, crack-prone shell. In high-wind Oklahoma, we lean toward the deeper, wider end of those ranges.
Gravel, Concrete, and Drainage
The order matters: gravel first, then the post, then concrete. The gravel base lets water drain down and away from the post instead of collecting at the base, which is the number-one spot a wood post rots. The concrete collar above it locks the post against wind.
Finishing the top of the concrete with a slope away from the post keeps rain from pooling against the wood. These small drainage details are what let a properly set post last for decades instead of rotting out at the ground line.
Bracing While the Concrete Cures
Bracing is the step that separates a plumb post from a crooked one, and it is the step most DIYers skip. Concrete does not grab instantly, so without a temporary brace a post will drift out of plumb before it sets, and then it is crooked for good.
The fix is simple: screw two braces to adjacent sides of the post, angle them to stakes in the ground, and check plumb one more time before you walk away. Leave them on until the concrete has set. Five minutes of bracing prevents a permanent lean.
Wood vs. Steel Posts: Setting Differences
Wood posts are traditional and economical, but their weak point is the ground line, where moisture and clay can cause rot over time, so drainage and a sloped concrete top matter most with wood. Pressure-treated posts resist this better than untreated.
Galvanized metal posts sidestep ground-line rot entirely and add wind resistance, which is why we use them on every wood fence we build rather than offering them as an add-on. They are set the same way, deep, plumb, braced, and in concrete, but you do not have to worry about the post rotting where you cannot see it.
Setting Gate and Corner Posts
Gate and corner posts carry more than a line post, so they are set deeper, in wider holes, with more concrete, and braced carefully. A gate post supports a swinging weight that constantly tries to pull it out of plumb, and a corner or end post anchors the pull of the fence.
Under-setting these is the top cause of sagging gates and leaning corners. Giving them extra depth and concrete up front is far cheaper than resetting them later, so they are the posts to over-build.
Setting Posts in Rocky or Hard Clay Ground
Not every hole digs easily. Much of the OKC metro has hard clay, and some areas hit rock, which slows the digging and can tempt a shortcut on depth. Resist it, because depth is exactly what resists wind, and the ground that is hardest to dig is often the ground where a shallow post fails soonest.
A power auger makes clay far easier than a hand digger, and for rock a rock bar or a rented auger with a rock bit gets through. If you genuinely cannot reach full depth because of solid rock, a wider hole and more concrete can partly make up for it, but get as deep as the ground allows. In the worst spots, this is a good reason to hand the job to a crew with the right equipment.
How to Reset a Leaning Fence Post
If a post is already leaning, you do not always have to replace the whole fence. A single leaning post can often be reset: dig out around it, straighten and re-plumb it, brace it, and pour fresh concrete, the same way you would set a new one. Done right, the reset post is as solid as the day the fence went in.
The catch is diagnosis. One leaning post from a shallow original set is a straightforward reset; a whole line leaning, or a post rotted through at the base, is a sign the fence needs more than a patch. We repair leaning posts and failing sections across the metro, and we will tell you honestly whether a reset will hold or the run needs rebuilding. Either way, catching a leaning post early, before it drags the neighboring panels out of line, keeps the fix small and inexpensive.
When to Call a Pro
Setting one or two posts is a reasonable DIY task. Setting a whole fence worth of posts, plumb, evenly spaced, and deep, in Oklahoma clay and wind, is where the work adds up and small errors compound into a wavy, leaning fence.
If you want the posts, and the whole fence, done right and backed by a warranty, that is our job. Metro Fence places posts to the proper depth and wet sets them in concrete across the OKC metro, with a one-year workmanship warranty on every install. A free on-site estimate is always available.
Good to Know
Frequently Asked Questions
In Oklahoma, concrete is the more wind-resistant choice, so we set posts in concrete over a gravel base. The gravel handles drainage and the concrete handles the load. Gravel-only setting can work for light fence in calm areas but offers less resistance to wind.
Fast-set concrete firms up in about 20 to 40 minutes, enough to remove braces, but keeps gaining strength for a day or more. Standard concrete cures over several days. Let posts set before hanging rails and pickets, and give gate posts extra time.
The usual causes are a hole set too shallow, no concrete, no bracing while it cured, or expansive clay soil and poor drainage working the post loose. In Oklahoma, wind then pushes it over. Proper depth, concrete, drainage, and bracing prevent it.
Yes. Concrete does not grab instantly, so without temporary braces a post will drift out of plumb before it sets and end up crooked for good. Brace two sides to stakes, check plumb, and leave the braces on until the concrete has set.
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