Repairing and Replacing Fence Posts

Fence-building and home improvement expert Jeff Beneke explains the process of repairing and replacing fence posts that have decayed or rotted.

| February 14, 2014

  • Drive shims into the footing on all four sides of the post.
    Illustration by Melanie Powell
  • Trim the shims level with the footing and caulk around the top to seal the joint.
    Illustration by Melanie Powell
  • In order to repair decayed fence posts, wood blocks and a temporary brace are used. The new post is bolted to the decayed post, stretching 2 to 3 feet above the ground and using 1/2 inch by 8 inch carriage bolts.
    Illustration by Melanie Powell
  • If a post resists being pulled out, attach a 2 x 4 lever to it with a lag screw. With one end supported by a wood or concrete block, lift the other end up to pull up the post.
    Illustration by Melanie Powell
  • To set a new post in an oversize hole, set the post in a fiberboard form and then fill the form with concrete.
    Illustration by Melanie Powell

Good neighbors make good fences and good fences require good planning, materials and construction. The Fence Bible (Storey Publishing, 2005) acts as a reference to construct and repair any fence that might be right for your property, with an explanation of project options and detailed step-by-step instructions from fence-building and home-improvement expert Jeff Beneke. The following is excerpted from chapter eight, “Repairing Fences and Gates.”

You can purchase this book from the MOTHER EARTH NEWS store: The Fence Bible

Correcting Footing Failures 

If the posts have loosened or fallen out of plumb, it is likely due to a problem with the footing or backfill. Concrete footings can crack or heave, and a tamped earth-and-gravel footing can soften over time. A failed concrete footing is hard to repair, and the best solution is to replace the fence post and footing. You can tighten the hold of an earth-and-gravel footing by digging out as much of the backfill as you can, replumbing the post, then backfilling and tamping. You might also try fastening pressure-treated shims to all sides of the post before backfilling and tamping.

If a concrete footing seems secure but the post has shrunk away from the concrete and loosened, drive pressure-treated shims into the concrete on all four sides of the post, checking for plumb as you do so. When the shims are tight, trim them level with the concrete and run a bead of clear silicone caulk around the top to seal the joint. This may not provide a long-term solution, but it can buy a few more years.

Mending fence posts that have decayed

Rotted posts can be replaced, with new posts being set in new footings in the same location as the old ones. But on some fences, this can be a challenging job that requires a lot of work and threatens the strength and integrity of the rest of the fence. In that case, it often makes better sense to try and reinforce the old post with another, partial post.

Begin by shoring up the fence on both sides of the bad post. Place blocks beneath the rails at the very least, and for a high and heavy fence I suggest you brace the top rail and infill from both sides. Remove the backfill down to the bottom of the post or, with a concrete footing, dig a new posthole right next to the existing one. Cut the old post off an inch or two above ground level. Remove the post; if the post is set in concrete, you should be able to wiggle it loose and lift it out with a helper or two. Clean out the hole, and make sure the fence is plumb.

2/23/2015 5:32:54 PM

My fence in my backyard has started to come loose. Turns out the footings are to blame for the wobbly fence. I took your advice on how to fix this problem by driving pressure-treated shims into the concrete, and that seemed to work. Is this a permanent fix or just a temporary one?

11/18/2014 3:05:50 PM

Try this easy method to replace rotted fence posts without digging -

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