Fencing in difficult terrain has options

A log fence is one of the many alternatives producers have when fencing in difficult terrain. | HEATHER SMITH THOMAS PHOTO

Building a good permanent fence can be challenging in rocky, frozen or swampy ground when it’s impossible to dig post holes efficiently, or set posts with a tractor-mounted post-pounder.

Most fences for cattle use barbed wire, especially for large pastures. A good barbed-wire fence is effective and cheaper to build and maintain than rail fences or netting, and lasts longer if properly installed.

Jason Nelson, who ranches in southern Alberta, does custom fencing, and says the key to a good barbed-wire fence is good braces.

In easy terrain on straight stretches without corners, Nelson puts a brace every quarter mile — at the end of every roll of wire.

“Low spots require additional braces, however, to make sure the tight wire doesn’t pull up posts. When we go through a gully we put a brace at the top on each side, but with small gullies we just put large-diameter eight-foot posts through the low spot,” he says.

Then the main wires can go straight across, with additional wires in the low spot.

“I also use eight-foot posts for my braces (so they can be set deeper) and make a 12-foot angle brace (going from the top of one post to the bottom of the other). These hold very well,” says Nelson.

Michael Thomas, a custom fence-builder near Baker, Idaho, generally secures rocks to the bottom wires in a deep gully or makes a rock basket at the bottom to anchor those wires.

If terrain is too rocky to drive wood posts, Nelson uses metal T-posts or posts made from sucker rod, with wire hooks welded on.

These usually drive down through rocks and don’t bend easily.

“We set wires in the hooks and take a pipe wrench and give the post a quarter turn and it locks the wires into place,” says Nelson.

Thomas says the options in rocky ground include digging holes with a backhoe, chipping away the rock (if it’s a formation that will chip and break), prying rocks out with a hand bar, or using a roto-hammer electric drill that runs off a portable generator.

“This works for drilling small diameter holes into solid rock to insert a steel post, or even a bigger hole for a brace post,” says Thomas.

In rocky terrain where it’s not too steep and there are surface rocks, he creates an above-ground basket/cage of rocks as a brace to anchor the fence. Stacked rocks can be secured with net wire, or a wire cage can be made to hold the rocks.

“A cage three to four feet in diameter makes a solid anchor to secure your wire and stretch it from there,” he says.

If terrain is too rocky to set wood posts, steel posts can usually be inserted deeply enough to hold, using rock baskets every so often for braces.

A jack-hammer hydraulic post pounder can usually pound wood posts through a foot or more of frost, and pipe posts will go even deeper. | HEATHER SMITH THOMAS PHOTO

When using a post pounder to set wood posts along a challenging fenceline, builders can use a metal “post” to create a pilot hole. The metal post will often go down through rocky ground if it’s not solid bedrock, pushing aside the rocks, or penetrating frozen ground, whereas a wood post would be forced out of line or shatter.

Thomas uses a seven-foot metal pilot post to create holes for wood posts in difficult conditions.

“The pilot post is only about three inches in diameter and creates a hole to start the wood post into. The pilot post is solid enough that you can drive it into just about anything but solid rock. The pointed bottom part is solid steel three feet long, and the rest is hollow, like well casing,” says Thomas. This makes it a little lighter to carry around.

“The top has a solid cap for the post pounder to hit. Drive that pilot post down as far as you can, then pull it out with a tractor loader. When you create a pilot post, make sure you have a way to hook a chain to it and pull it back out. Insert a wood post into the pilot hole and drive it — forcing it into the slightly smaller hole — and the post will be very solid and secure,” says Thomas.

Some people use pipe posts — oil field drill steel pipe is great for making braces in rough terrain and won’t burn in a wildfire.

Oil field pipe is surplus and can be purchased reasonably. It comes in 30- to 33-foot lengths but can be cut into post lengths with an electric hand-held band saw. With a jack-hammer type hydraulic post pounder, pipe can be driven into any terrain — solid rock, frozen ground or bogs.

On steep slopes Thomas uses a pounder mounted on a skid steer because it has better stability than a tractor.

In steep areas, Nelson uses a pounder mounted on the back of a track machine that can go up steep slopes without tipping over.

“You just walk beside this machine and drive it from the ground with a joy stick; you don’t have to be on it to drive it. This is safer, especially going through areas where it’s too steep to take any kind of vehicle or tractor,” he says.

“It’s handy for one person fencing alone because you can drive it as you walk beside it, and stop it where you want to set a post.”

This can save time and labour and one person can set a lot of posts.

Metal posts can often work when a fence has to go through wet areas and sloughs where it would be difficult to drive wood posts.

“I’ve had to do some fencing through bogs, and used seven-foot T-posts. They went far enough down to hit solid ground where they could hold,” says Nelson.

In some situations where the bog is too deep to hold posts, a person can build an above-ground jack fence.

This is often best accomplished in a dry season, or in winter when the bog is frozen, so builders can get around without sinking into the mud.

With a jack-hammer hydraulic post pounder a person can usually pound wood posts through a foot or more of frost, and pipe posts will go even deeper. When setting wood posts through deep frost, a metal pilot post to start the hole can help.

If frost is too deep for driving posts, fire is a common way to thaw ground for post holes. Some people burn an old tire over the spot that needs to be thawed, burning at night so the ground is thawed underneath by morning. But burning tires is illegal in most regions, and fumes from the smoke are toxic and nasty-smelling. There’s also no way to control the fire; wind might spread it to dry grass, buildings, or haystacks.

A safer way to thaw ground is with a metal “oven” to contain the fire over each spot.

Old metal tubs or half barrels can be turned into “ovens” to thaw frozen ground before driving in posts. | HEATHER SMITH THOMAS PHOTO

Old metal tubs or half barrels work well. A cutting torch can be used to create small vent holes along the bottom edge (to draw air in, to keep the fire going) and a five-inch-diameter hole in the top of each oven for the smoke to go out. A screen over the smoke hole, weighted down with rocks, contains any sparks or embers.

Fires can be set under several ovens, letting them burn while working on other parts of the fence, and the ground underneath may be thawed within a few hours.

“In places where frost is really deep, scoop out the embers after the fire dies down, dig down through the thawed dirt, put ember/coals back in, and add more wood,” says Thomas.

The ground underneath a metal “oven” may be thawed within a few hours. | HEATHER SMITH THOMAS PHOTO

Another alternative in difficult terrain is a jack fence,(buck fence) or worm fence.

A worm fence is created by stacking logs or large-diameter poles on one another, interlocking in two directions. The finished fence is a continual series of corners/angles.

A jack fence (poles nailed/screwed onto jack legs) works well where ground is too rocky or boggy to set posts, but in windy country must be anchored so it won’t blow over.

“To keep it from tipping over, hang a large rock under one of the jacks every so often, or make a small rock basket under some of the jacks, with the jack secured to it,” Thomas says.

This brace was built at the top of a hill. | HEATHER SMITH THOMAS PHOTO

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