Digging H-Brace Corner Post Holes for a Barbed-Wire Fence With a Post Hole Digger: 44 to 48 Inches Deep, Gravel in the Bottom, and a Lean Away From the Pull

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Every barbed-wire fence on a dry, rocky place lives or dies at its corners. The line posts just hold the wire up; the brace posts take the whole pull.

For an H-brace corner, dig the anchor and brace post holes about 44 to 48 inches deep, keep them barely wider than the post, drop two or three shovels of gravel in the bottom, set each post in the center, and tamp the backfill in thin layers. Lean the anchor post slightly away from the pull.

What the specs ask for

The British Columbia four-strand barbed wire fence specifications call for corner and gate brace posts 8 feet long and 5 to 6 inches thick, set at least 44 inches deep with a target of 48. They list a 10-foot horizontal rail for corner braces.

Virginia Cooperative Extension's guide to constructing high-tensile wire fences says to set anchor posts at least 3-1/2 feet deep, put two or three shovels of gravel in the bottom of each hole, and set tamped posts in the center of the hole. It also says anchor posts should lean slightly away from the direction of pull so they stand straight once the wire is tensioned.

The same Virginia guide notes that a driven post is 1.7 times as strong as a tamped one. On ground where a driver bounces off rock, a dug and well-tamped hole is the option most of us actually have.

Laying out the corner

1. Drive a stake at the corner and stretch a string down each fence line.
2. Measure out along each line for the brace post. The spacing has to match your brace rail, so cut or buy the rail first and measure off it.
3. Mark each hole center with spray paint, not a stake you will trip over.
4. Call 811 before the first bite, even out in the sagebrush.

Digging each hole

1. Wrap a band of tape on the digger handles at 48 inches from the blade tips so you can read depth without a tape measure.
2. Break the crust with straight, hard drops, then spread the handles to grab and lift. Dump the spoil on a tarp on the side away from the fence line.
3. When the blades ring on a rock, pry it loose with a digging bar and lift it out with the digger. Do not try to chew around it.
4. On caliche, pour a gallon of water in the hole and let it soak in overnight. The hard layer softens enough to cut the next morning.
5. Keep the hole only an inch or two wider than the post all the way down. A belled-out hole leaves loose fill that lets the post walk.

A fiberglass-handled post hole digger is the right tool for this depth. Fiberglass shrugs off the prying that snaps a dry wood handle in rocky ground.

Setting the posts

1. Drop two or three shovels of gravel in the bottom of each hole and tamp it flat.
2. Stand the post in the center of the hole.
3. Lean the anchor post an inch or so away from the direction the wire will pull.
4. Backfill 3 or 4 inches of soil at a time, picking out the rocks bigger than a fist, and tamp each lift hard before adding the next.
5. Mound the last of the soil around the post so water runs away from it.

The classic mistake is filling the whole hole and tamping only the top foot. The post feels solid until the wire comes tight, then it leans toward the pull and the whole corner goes slack.

Gear and next steps

Tractor Supply stocks treated brace posts, digging bars, and post hole diggers in the same aisle. A hand tamper or the flat end of the bar does the packing.

Once the corner is solid, the line posts come next; here is a walkthrough on hand-digging 48-inch gate post holes that covers the same depth on a gate.