Cracked concrete fence posts can be repaired, but it is important to identify the underlying cause of the damage before attempting to fix it. DIY enthusiasts can repair minor damage with epoxy putty, while more severe damage may require a complete replacement of the post. In either case, it is important to ensure that the new post is properly supported and that the concrete is mixed correctly. To repair minor damage, start by removing any concrete from the iron drill bits.
Then, activate the epoxy putty and fill the damaged hole, crack or corner with it. Press as much epoxy as possible into the area and use a towel to soften it and press it inward to fill the crack. If the pole has a decorative square base, try to form the epoxy in that shape. Allow the epoxy to sit for at least two hours before moving on.
For more severe damage, you'll need to shore up the fence on all sides of the bad post and place blocks under the rails. Then, dig a new post hole right next to the old one and cut the old pole one or two inches above the ground. Remove the pole without concrete and lift it with an assistant. Clean out the hole while making sure that the fence is plumbed.
Typically, ⅓ to ½ of the fence post should be able to sit comfortably in the pit with an additional 6-inch depth that will be filled with gravel for proper drainage. When using concrete tools, such as a manual concrete mixer, it is important to follow all instructions for both the mixer and concrete mix itself. Start shoveling it into the hole, surrounding the pole with concrete. When they are tight, trim them to the level of the concrete and apply a transparent silicone putty bead to seal the joint.
In cases of acute damage or even mild chronic damage where the underlying factor has been treated and alleviated, a rapid fence repair product may be a better choice than attempting to repair it yourself. If an entire fence post is only a year or two away from needing replacement, then it would make more sense to complete that replacement immediately rather than repair it.