Proper Fence Brace Construction
By Kyle Bading and Randy Lenz, Stay-Tuff Fence
The foundation of every good fence is its bracing. Without solid, well-built braces, your fence will fail. Braces come in a variety of configurations depending on the purpose, number of posts and soil type. The purpose of the brace is to withstand the force of the fence load and transfer it to the surrounding soil. A brace is needed at corners, on either side of a gate, and at every point where the fence starts or stops.
The main parts of an end brace include:
- End Post — this is the anchor of the fence and the post the fence wire is attached to.
- Brace Post — this is the second post in the fence and used in conjunction with a cross member to hold the end post in place.
- Cross Member — this can be wood or pipe and connects the brace post to the end post and allows the two posts to share the load of the fence.
- Brace Pins — used to hold the cross member in place. 1/2” or larger hot dip galvanized pins work best. Screws, nails, bolts, smaller pins, etc., will make a weaker connection that will not hold up over time and should be avoided.
- Twitch Wire — this ties the two posts together and transfer forces between the posts. Without a twitch wire, the entire brace will lean in the direction of the fence pull. Two wraps of 12.5-gauge high tensile smooth wire work best. Using an inline strainer instead of a twitch stick makes for easy tightening during installation and easy adjustment/re-tightening if needed.
Braces can be built from either wood or pipe. If using wood, never use milled lumber such as landscape timbers or 4x4s. They will not withstand the forces on the brace and will warp over time. Always use treated round posts. Be sure not to cut into the post, either to notch for the brace or cut off the top; this opens up the protection and will prematurely weaken the post. Pipe should be galvanized or painted. To paint an un-galvanized post, always treat it with OSPHO or other rust treatment prior to painting.
The best method to install posts is driven. This is because a driven post can withstand greater force than one placed in a drilled hole filled with soil or one set in concrete. If driving is not an option, drill a hole and fill it with the soil that came out of the hole and tamp well. If using concrete, fill the hole half full of concrete and put tamped soil on top. Even with concrete, the posts must be placed deep enough or movement will occur. For loose or sandy soils, the posts must be deeper and you may consider a 3-post brace, sometimes called a Double H brace, to spread the load and keep the brace from sliding.
Post depth is also critical. For a 4-foot fence, the posts should be at least 3.5 to 4 feet in the ground. For loose or sandy soils, the depth would need to be increased. For an 8-foot fence, the posts should be 5 to 6 feet.
The distance between the end post and brace post is critical to the success of the brace as well. The spread between the posts must be at least 2 times the height of the fence, but 2.5 times is better. In other words, for a 4-foot tall fence, the distance between the posts must be no less than 8 feet, and preferably 10 feet.
“Proper Fence Brace Construction” is excerpted from the February 2017 issue of The Cattleman magazine.