Wire fences always operate under some kind of tension — that’s why corners and curves need stronger bracing than posts that sit along the fence line. If corners can’t resist this constant inward pull, they’ll eventually tilt and cause the fence wire to sag. This is especially true with high-tensile fences, though all fencing types need solid bracing.
When it comes to resisting the forces of fence tension, you have three options: a traditional multipost corner, a weighted wooden crib and a little-known but highly effective option called an “earth anchor.”
Corner Posts: Multipost Corners
Two or three 6- to 8-inch-diameter wooden posts are connected with diagonal or horizontal posts and tightly twisted wire. This arrangement keeps the ends of the posts vertical, despite the lateral pressure exerted by the pull of the fence wire. A single post would tilt under this strain, no matter how deeply it was set in the soil.
Corner Posts: Weighted Cribs
Multipost corners work well, but only if you have more than 3 feet of soil. In fields where the dirt is shallower than that, weighted cribs are the most reliable option. These use a series of criss-crossed 4- to 6-inch-diameter rot-resistant logs, spiked together to create a vertical cage covering a 3- to 4-foot-wide square area. Fieldstones are loaded into the crib, creating a sturdy anchor that can last up to a half century. Cribs are an ideal way to support gates on shallow soil, too.
To make one, clear the area of stones and brush, lay down your first pair of logs and then add a second pair on top, fastened with 8- or 12-inch galvanized spikes. Make sure additional levels rise plumb by using a 4-foot level at the corners. Keep building until the sides are 4 to 5 feet tall and then fill the structure at least half full with fieldstone.
Corner Posts: Earth Anchors
If you have plenty of soil but don’t want to install multipost corners, then consider using an earth anchor. This is a steel shaft with an enclosed eye on top and a 4-inch-diameter screw-shaped bottom. Set the point against the soil, put a crowbar through the eye and then turn the anchor clockwise. As the screw tip digs into the ground, it draws the whole anchor into the soil with it. Keep turning until only the eye remains visible. With the coarse threads of the device buried 2 or 3 feet deep into undisturbed soil, the earth anchor will stay secure even if the surrounding soil freezes and heaves. Simply run four or five strands of 12.5-gauge fence wire back and forth from the post to the eye in the top of the anchor and then twist the wires as a group to apply tension. As long as the shaft of the earth anchor is aligned with the brace wires, the anchor will not pull out.
If you have a traditional multipost corner in heavy clay soil that pushes the posts up due to frost heave, install an earth anchor as additional support. The earth anchor will protect the end posts against any amount of frost heave, and your problem will be solved.
Read more: Choosing the correct type of perimeter fence depends on the type of livestock you keep, your terrain and other factors. Learn more about different types of homestead fencing in Types of Fences for the Homestead.