To build a rail fence, or any other fence for that matter, isn’t complicated. There are a few fundamentals to follow, no matter what type of fence you want to build, or how long you want it to be. And overall, it’s a process that follows common sense every step of the way. So let’s start with a quick checklist of tasks you need to complete before you ever dig your first post hole.
Know your boundaries
The last thing you want to do is build your fence on your neighbor’s property. So no matter how sure you are, make sure you refer to a legal property description of your land showing the exact property line locations.
Get any needed permits
Your project may or may not need them, depending on the zoning laws of the municipality where you live. And while you’re at it, check to see if there are any zoning laws regarding height, length, style, materials, etc.
Mark any utility lines
Call 811 for Common Ground Alliance (CGA). CGA is a non-profit organization with 1,400 members and sponsors that launched the “Call Before You Dig” campaign several years ago. Call 811 and your underground utility lines will be marked for free. Be sure to mark where you intend to build your fence with white flags so the utility markers know where to focus their attention.
Sketch it out
The height and length of the rail fence will allow you to determine how many posts and rails you need. This sketch will also give you a visual reference guide to follow, which may come in handy, no matter how crude it may be.
Acquire your materials
If you’re planning a particularly long fence, you may or may not want to acquire all the materials at once. That’s up to you. But always remember, once a rail is cut, it’s cut forever. If you plan to have your fence turn any 90-degree corners, you’ll want to include specially cut corner posts to accommodate rails running in two directions.
Time to start measuring
Now you’re ready to carefully measure and mark the location for your support posts, starting with the corner posts.
Drive a heavy wooden stake into the ground a couple feet past where you want to locate each end or corner post. Tie a length of heavy twine to the corner stake 12 inches (30.5 cm) above the ground and stretch it tightly to the other end stakes. If you’re building a rather long fence, you’ll want to limit this to a manageable length, one that will allow you to stretch the string good and tight.
If you want to make sure the corner is square, use the 3-4-5 method. Place a piece of tape on one string 3 feet (91.4 cm) from the stake in one direction. Place another piece of tape 4 feet (121.9 cm) from the stake on the other piece of string. Now, measure the distance between the pieces of tape. It should be 5 feet (152.4 cm). If it isn’t, adjust the angle until the distance between the two pieces of tape is 5 feet (152.4 cm).
Next lay out your rails on the ground along each run, overlapping each end by 6 inches. Where the rails overlap is where you’ll dig your post holes. Mark those spots with stakes or spray paint. Mark each post hole location the same distance from the string line. About 12 inches.
The posts you’ve bought to build a rail fence should already have holes cut out for the rails to fit in. Clearly mark each post 36 inches (91.4 cm) up from the bottom. You’ll use this mark to make sure you set each post the correct depth by aligning it with the string you’ve set 12 inches (30.5 cm) off the ground. This way your post will be set 24 inches (61 cm) deep and all the rail holes should be the same distance off the ground as well. As you begin setting your posts, add some gravel to each hole as needed to bring the depth up to 24 inches (61 cm) and to provide good drainage and footing for the post.
Time to dig your post holes.
Digging post holes can either be a piece of cake or a pain in the back depending on a few variables – most notably, the type of soil you’re digging in, the number of holes you have to dig, and the tool you’ll be using to dig them.
Digging post holes by hand is hard work, even under the best conditions. If you’re only digging five or six holes in fairly soft soil, it might take you 30-45 minutes per hole to complete the job. If the soil is rocky or heavy clay, it could take longer. So in this video, we’re using a Rotomec PHD400 Post hole Digger (US CA) with PHA106 6-inch Auger (US CA). We’ve attached that package to a John Deere 4066R (US CA) Utility Tractor.
Dig your post holes at the ground marks you made earlier. Measure from the bottom of the hole up to the string that is 12 inches (30.5 cm) off the ground. Use a tamping tool to compact any loose soil at the bottom of the hole. Add gravel as necessary to make the hole 24 inches (61 cm) deep. In case you hit a large rock that won’t budge, you can cut up to 6 inches (15.24 cm) off of the bottom of the post, giving you about 18 inches (45.72) of actual depth. Posts set less than 18 inches (45.72 cm) deep, however, can’t be counted upon to be as stable as they should be.
Starting at your first corner, set the specially notched corner post upright in the hole and make sure its depth is correct and the rail holes are pointing in the right directions. Then start filling in the hole with dirt until the post becomes somewhat stable. Using a level, adjust the post until it is plumb all around. Concrete is the most dependable filling material, though 24 inches (61 cm) of well-compacted soil is acceptable.
Once the post is set, place the notched rails in their respective holes and make sure the holes you’ve dug for the next posts are in the right spots. Then set those posts following the same steps you used for setting the corner post. Place the notched rails in those posts, and proceed in that fashion with the rest of the fence.
And remember, always read the Operator’s Manual before operating any piece of equipment and follow all operating and safety instructions.