Spring Fencing Projects - Repairs and New Fences
Published on Thu, 03/12/2020 - 9:49am
Spring Fencing Projects - Repairs and New Fences
By Heather Smith Thomas
Post permanent pasture fences for cattle utilize barbed wire, net wire or multiple strands of high tensile electric wire, stretched tightly and secured to well-set posts. In some kinds of terrain, however, a jack fence (poles/rails nailed or screwed to jack legs) is more feasible than trying to set posts in deep mud or solid rock. Any pole fence will need periodic maintenance to make sure none come loose, and poles/rails will need to be replaced; the lifespan of a wood fence is usually 20 years or less. A properly built wire fence will last longer.
The key to a good wire fence is good braces. Michael Thomas (Thomas and Son Custom Fencing, at Baker, Idaho) says a barbed-wire fence can be built in nearly any kind of terrain, as long as you match bracing to the terrain. “In flat country you can go a lot farther between braces, but if geography is variable you need to put in more braces. Don’t stretch wire through low places or over high places without bracing,” he says.
It’s important to tie off the wire at a brace, securing it solidly to the brace posts rather than just stapling it to the posts. “When we rebuild fences for people and have to take apart and remove the old fence and build a new one, we often find the wires were not secure. Though they went to the trouble to put in braces at appropriate locations, they didn’t break the wire to pull to the brace; they just run the wire by and stapled it to the brace posts. This defeats the purpose of the brace because there is some give and movement of that wire. You need a solid attachment to the brace posts; otherwise you are putting all your faith in just the staples and they eventually work out. The wire will have some give through the staple even before it comes out,” says Thomas.
In low spots, like a deep gully, a good brace will generally hold the fence down if the posts are well set, without additional anchors. “We don’t use anything less than 6-inch diameter posts for braces in that kind of country, and you need at least a 5-inch post for braces. Smaller posts don’t have as much anchor quality,” he says.
“In washes and gullies that have washed to bedrock, your chances of setting a secure post are limited. Sometimes you can set two posts—one on either side of the rock. This gives you something secure to pull the wire to in that low spot. In extreme cases, where we can’t set posts, we gather rocks (in rocky terrain) to make a rock basket as an anchor for the fence in that low spot.”
When stapling wire to posts, a two-inch barbed staple works better than 1½ inch staples. “The small ones are cheaper but won’t stay in as long. I recommend a 2-inch minimum, and the barbed ones won’t pop out as readily. Weather takes staples out eventually, no matter what they are, so the longer the shanks, the longer they last before they come out. Frost pushes them out, and wildlife hitting the fence can pop them out,” Thomas says. The better you can build it the first time, using good materials, the longer the fence will last and the less maintenance it will take.
Posts should always be adequately treated (enough treat to penetrate deeply into the wood and not just superficially) and far enough up the post so that the treat extends above ground level when the post is set. “Sometimes you want a post deeper, to make sure it will hold in a certain situation, but there’s no point in setting it deeper than the treat line, or it won’t last. A post generally rots off at ground level, rather than below the ground,” says Thomas.
Posts tend to last longer in dry ground and dry climates, but the biggest factor in how long a post lasts is the treat—to keep the wood from rotting—and the greatest risk area for rot is at ground level. “Water itself is not as hard on wood posts as continual exposure to sunlight, oxygen, and water. That combination breaks down wood. In our reconstruction jobs, we’ve pulled thousands of old posts out of the ground, and the points on driven posts looked as good as the day they were put in, even in a swamp, yet the post was rotting off at ground surface where it meets the air. That’s the environment where all the conditions that deteriorate wood (including bacteria) are maximized, and why you should never sink a post down past the treated level. The treated portion should extend at least a couple inches aboveground after the post is set,” he says.
Properly treated round wood posts and poles are the preferred choice of the agricultural industry for fencing and other ranch and farm products. These materials are also popular for ranch perimeter fencing, and are frequently specified by highway and park departments.
Pressure treatment is the process where chemical preservatives are forced into wood cells in an enclosed cylinder or retort, to provide protection against decay, fungi and insects. Only Wood that is adequately dry prior to treatment will accept proper chemical penetration and retention. Wood cells full of moisture cannot accept proper chemical penetration. Premature failure of round wood fence posts primarily occurs because of improper preservation procedures.
The lifespan of a typical wood post can increase up to tenfold when treated properly with a preservative. Treated posts and poles are strong, good looking, easy to install, maintenance free and lasts a long time. Properly treated wood is safe when used in accordance with the environmental protection agency (EPA) and industry-approved guidelines.
The advantage to metal posts is that they don’t rot. Even though they may rust they last much longer than wood. “When fencing for livestock, use heavy duty T-posts. There are several different qualities; the heavy-duty ones will outlast the others because they won’t be easily bent. You can afford the good ones if you buy the right height (not paying extra for extra length of posts if you don’t need a really tall fence),” says Thomas.