Cure for the Common Fence

Image Gallery iStockPhoto.com/Debi Bishop

Travel any country road, and you’ll see plenty of fences with sagging wires or mesh so loose that all but the most timid livestock will laugh at them. Focus on the corners, and you find posts that appear to rise miraculously out of the ground, tilting precariously. Fence failures such as these are commonplace, but most of those sagging wires are caused by an anchor (corner or end) post being pulled from the ground by the tension of the wires themselves.

Well-braced fence ends and corners aren’t rocket science, but you need to consider a little physics, or follow the advice of experts, to get them right. And sometimes 6 inches make all the difference between a lifelong fence installation and one that fails in a few years.

Why bother with braces?

The typical tensioned-wire fence exerts a minimum of 1,000 to 1,500 pounds of pull on an anchor post. Likewise an anchor post serving as a corner post must withstand that much pull in two directions. Soil movement due to temperature and moisture fluctuation, and livestock or wildlife collisions with the wire can easily increase the pull to 2,500 pounds or more.

Obviously, the magnitude of these loads is more than an average post can bear for any extended period, but, with a bit of thoughtfully placed bracing, a 6-inch-diameter wooden end post will offer an anchor capable of withstanding temporary pulling loads up to about 6,000 pounds.

A brace by any other name …

Many brace styles have been used successfully around the world. A few rely on an earth anchor or deadman (such as a large rock or log) buried in the ground and wired to the anchor post opposite the pull imposed by the fence. While these are inexpensive and easy to install, they are not effective when the fence follows or ends on property lines because they extend outside the enclosed area (they are also easy to trip on, catch mowers and injure livestock).

Other brace styles use a combination of vertical posts, horizontal or diagonal rails and wire to help anchor the fence. These are installed in the fence line between ends or corners, so they are perfect for perimeter fences that follow property lines.