How to Repair a Leaning Fence Post
Straighten and secure a leaning wooden fence by propping it plumb, excavating around the compromised post, bolting a heavy-duty repair spur, and pouring fresh concrete.
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🧰 Required Tools & Equipment
- ✓ Post hole spade
- ✓ Spirit level
- ✓ Cordless drill and driver bits
- ✓ Claw hammer
- ✓ Trowel
- ✓ Socket wrench set
📦 Materials & Supplies
- ✓ H4 treated timber repair spur (100x100mm)
- ✓ Fast-setting concrete mix (2-3 bags)
- ✓ Galvanised coach screws with washers (M10 x 150mm)
- ✓ 2x4 timber props (approx. 2m long)
- ✓ Timber ground stakes
- ✓ Clean water
⚠️ Safety Checkpoints & Warnings
- • Check for underground utilities (gas, power, water) before digging around the post base.
- • Wear heavy work gloves and safety glasses when handling timber and power tools.
- • Wear an N95 dust mask and waterproof gloves when mixing and placing dry concrete.
📋 Step-by-Step Guide (6 Steps)
Brace and Plumb the Fence
Push the leaning fence back into vertical alignment while monitoring a spirit level against the post face. Drive a wooden stake into the ground 1.5 meters away on the leaning side. Screw a 2x4 prop from the top third of the fence post down into the ground stake to lock the fence plumb.
- • Spirit level bubble is centered on both the front and side faces of the post.
- • Diagonal 2x4 timber prop is firmly screwed into both the post and the driven ground stake.
- • Only checking plumb on one side of the post.
- • Relying on hand pressure without securing a solid ground prop before digging.
Excavate Around the Damaged Post Base
Use a post hole spade to dig out soil and broken concrete around the leaning post. Clear a trench roughly 200mm wide and at least 450mm deep along the side where the repair spur will sit. Expose solid wood beneath any surface rot and clean loose dirt from the post cavity.
- • Clean, deep hole beside the post reaching at least 450mm depth.
- • Soil and loose debris cleared away from the post face to reveal solid wood.
- • Digging a wide shallow hole rather than a deep, narrow trench.
- • Leaving loose soil at the bottom of the excavation.
Position and Clamp the Repair Spur
Lower the treated timber repair spur into the excavated hole tight against the sound face of the fence post. Ensure the spur extends at least 400mm into the ground and 400mm above ground level. Clamp or temporarily hold the spur flush against the post while confirming vertical alignment.
- • Repair spur rests flat against the post face with no large gaps.
- • Spur extends both deep into the hole and well above the ground line.
- • Placing the spur on the rot-weakened side without checking for solid core timber.
- • Setting the spur too high so it lacks ground embedment.
Bolt the Spur to the Existing Post
Drill pilot holes through the repair spur into the solid timber of the original post above the ground line. Drive M10 galvanised coach screws fitted with washers through the spur and deep into the post using a socket wrench or impact driver. Install at least two to three screws staggered vertically.
- • Galvanised coach screws pulled tight with washers flush against the timber.
- • Spur and post locked firmly together with zero play when shaken.
- • Skipping pilot holes, causing the treated spur to split along the grain.
- • Placing screws too close together in a straight line instead of staggering.
Pour and Crown the Concrete Footing
Fill the excavated hole around the spur with fast-setting concrete mix and clean water according to package directions. Tamp the wet mix with a timber offcut or rod to eliminate voids. Shape the top surface with a trowel into a slight slope shedding water away from the timber base.
- • Concrete fills the cavity to ground level around the spur.
- • Top surface is smooth and sloped downward away from the timber edges.
- • Leaving a dish or trough around the post that collects rainwater and accelerates rot.
- • Pouring dry mix without sufficient water penetration.
Cure and Remove Temporary Braces
Allow the concrete footing to cure undisturbed for at least 1 to 2 hours before removing support braces. Unscrew the 2x4 prop from the fence post and ground stake, then pull the stake out. Perform a final firmness test by pushing gently on the fence line.
- • All temporary braces and ground stakes removed from the work area.
- • Fence stands straight, plumb, and rigid under moderate manual pressure.
- • Removing braces before fast-setting concrete has fully hardened.
- • Yanking braces off and stripping screw holes in the fence rails.
Credit: inspired by an original tutorial by Mitre 10 New Zealand — watch the original on YouTube.
Don’t have everything?
- No H4 treated timber repair spur? Heavy-duty steel fence post repair anchor / spur bracket
- No Socket wrench set? Adjustable crescent wrench
- No Post hole spade? Narrow trenching shovel or heavy garden spade