Fence Repairs That Last: How to Set Posts Correctly (Depth, Drainage, and Footing Tips)

If your fence keeps leaning after every storm or sagging a few months after a “fix,” the problem usually isn’t the boards—it’s the posts. Fence posts are the structural backbone of the entire line. When they’re set too shallow, poorly drained, or out of plumb, even the best rails and pickets won’t stay straight for long. In this guide, you’ll learn why repairs fail when posts aren’t set correctly and exactly how to set fence posts so your repairs actually last.

Why Most Fence Repairs Fail

When a fence fails, the failure almost always begins at the post. That’s because posts do the heavy lifting:

• Transfer wind loads and weight into the soil
• Resist lateral forces that cause racking and lean
• Establish alignment, height, and gate function across the fence run

If the foundation (your post and footing) is wrong, cosmetic repairs won’t hold up. Think of replacing a warped picket on a leaning post like putting a fresh tire on a bent axle—short-lived at best.

The Forces Working Against Your Fence

• Wind pushes panels like sails, stressing posts at ground level.
• Freeze–thaw cycles expand and contract soil, lifting poorly designed footings (frost heave).
• Water pooling around wood posts accelerates rot and loosens backfill.
• Soft or disturbed soil settles over time, creating wiggle that turns into a lean.

Common Post-Setting Mistakes That Sabotage Repairs

1) Holes Too Shallow

• Rule of thumb: set posts at least one-third of the above-ground height and below the local frost line.
• Typical depths: 24–30 inches for 6-foot fences; 36 inches or more for taller, wind-exposed, or gate posts.
• Shallow posts rock loose quickly in wind and freeze–thaw cycles.

2) Wrong Footing Choice (or Poor Design)

• Concrete collars are strong but can trap water if shaped like a cup.
• All-gravel footings drain well and are serviceable in sandy/loamy soils, especially for wood posts.
• Best practices:

- Wood posts: gravel base for drainage, optionally a concrete collar in the upper third for rigidity, and a crowned top to shed water. - Metal/vinyl posts: full concrete footings are common—bell the base and slope the top.

3) No Drainage Around the Post

• Water + wood = rot, and water + freezing = heave.
• Add 3–4 inches of angular gravel at the base of each hole and slope the top of concrete away from the post. Avoid “birdbaths” that hold water.

4) Out of Plumb and Unbraced During Set

• Posts must be plumb in both directions. Even a small lean compounds across the run.
• Without temporary bracing, posts drift while backfilling or while concrete cures.

5) Poor Backfill and Compaction

• Loose soil settles, creating movement and gaps.
• Backfill in 6–8 inch lifts and tamp each layer; use angular gravel when possible for better lock-up.

6) Inconsistent Spacing and Underbuilt Gate Posts

• Overspanned panels flex in wind and overload posts.
• Gates concentrate load: use larger posts (6x6 wood or steel), deeper footings, quality hinges, and robust latch backing.

7) Wrong Post Material or Treatment

• Non-rated lumber rots fast in ground contact.
• Use UC4A/UC4B pressure-treated wood; seal cut ends with end-grain preservative.
• Consider steel posts with wood adapters for wet, clay, or high-wind sites.

8) Reusing Disturbed Holes

• Old holes often have poor bearing capacity.
• Enlarge and bell the base, or shift a few inches to bite undisturbed soil.

The Right Way to Set Fence Posts

Plan and Layout

1. Call before you dig to locate utilities.
2. Verify property lines, setbacks, and HOA/code requirements.
3. Stretch a tight string line to establish alignment and mark consistent post spacing (commonly 6–8 feet depending on panel type).

Dig the Correct Depth and Diameter

• Depth: below the frost line or at least one-third of fence height.
• Diameter: about 3x the post width (a 4x4 post often needs a 10–12 inch hole). Bell the bottom wider to resist uplift.
• Tools: clamshell digger, power auger, digging bar; shape by hand in rocky soils.

Choose Gravel vs. Concrete Based on Soil and Fence Type

• Well-draining soils (sand/loam): compacted gravel footings can be durable, drain well, and simplify future replacements.
• Heavy clay or poor drainage: use a gravel base plus a concrete collar; crown the top to shed water.
• Tall fences or high-wind areas: deeper holes, belled footings, and concrete are typically warranted.
• Wood posts: keep end grain dry; consider post sleeves or steel posts with wood rails for longevity.

Set, Plumb, and Brace

• Add 3–4 inches of compacted gravel to the hole bottom.
• Insert the post, align to the string line, and check plumb on two faces with a 2- or 4-foot level.
• Brace with stakes and kickers before backfilling so the post can’t drift.

Backfill and Cure Correctly

• Concrete: pour in lifts, rod or vibrate to eliminate air pockets, and slope the top away from the post. Allow at least 24–48 hours before loading; longer in cold weather.
• Gravel: add in 6–8 inch lifts and tamp aggressively. Re-top after the first heavy rain if it settles.

Adapt to Tough Sites

• Slopes: step the fence and keep posts plumb; adjust rail heights rather than tilting posts.
• Soft/peaty ground: increase depth and diameter; consider helical anchors or steel posts.
• Coastal/high-wind zones: tighter spacing, deeper/belled concrete footings, and upgraded gate posts.

Diagnose Your Fence: Repair or Replace?

Ask these questions before you start fence repair:

• Is the post structurally sound? Probe at and below grade. Punky or waterlogged wood should be replaced.
• Is failure due to shallow depth or poor backfill? Re-setting in a proper footing could solve it.
• Are multiple posts failing? Labor savings often favor a rebuild with correct spacing and footings.
• Are gate posts leaning or undersized? Upgrade to larger posts and deeper, reinforced footings.

Quick rule: Repair if the post material is solid and you can correct depth/drainage. Replace if rot, rust-through, undersizing, or widespread failure is present.

Tools and Materials Checklist

• Post hole digger or power auger
• Level (post level or 2–4 foot) and a tight string line
• Angular gravel (3/4 inch), fast-setting or standard concrete mix
• Stakes and scrap lumber for bracing
• End-grain preservative for cut wood posts
• Galvanized or powder-coated hardware; heavy-duty hinges and latches

Pro Tips to Make Repairs Last Longer

• Pre-plan gate locations and overbuild them—this is where most fences fail.
• Seal all cut ends of pressure-treated lumber to slow moisture uptake.
• Don’t rush the cure. Loading posts too soon introduces a permanent lean.
• In clay soils, drill small weep holes through the concrete collar away from the post or use a gravel chimney to promote drainage.

Conclusion: Solid Posts, Solid Fence

Most repeat fence repairs fail for the same reason: posts weren’t set correctly. Get the fundamentals right—depth below the frost line, proper diameter and bell, real drainage, true plumb with bracing, and well-compacted backfill—and your fence will stay straight through storms and seasons.

Ready to fix that leaning fence for good? Start by inspecting your posts and planning a proper footing. If you’d rather not dig in, consult a local fence contractor and ask exactly how they set posts (depth, drainage, and footing). A solid answer now saves you from another repair later.