How to Build a Horizontal Fence for a Modern Look

Begin your fence construction by mocking up a layout in your yard. Use a string line and stakes to mark the fence line. Next, identify your post locations. Measure the distance between each post so each board runs from the center of one post to the center of the next. 

For example, if your plan calls for 6-foot-long boards, space each post 6 feet and 3 1/2 inches apart to account for the length of the board and the 3½-inch width of each four-by-four post. As you measure, mark each post hole location with spray paint. 

As you plan your layout, prep your yard. Clear away any brush to make way for your new fence. Use a shovel and metal rake to smooth out any sharp changes in slope, leveling your lawn to make installation easier.

Use a post-hole digger to dig holes at your marked post hole locations. As a general rule of thumb, your posts should be 2 feet longer than the fence. If you’re building a 6-foot-high fence, you’ll need to use 8-foot posts. A 4-foot-high fence would require posts that are 6 feet long. 

Since you’ll add a 6-inch layer of gravel to the bottom of each post hole, you’ll need to dig each hole 30 inches deep. The diameter of the post holes should be about three times the width of the post to ensure it has a solid base that can support the weight of each fence panel. 

Add about 6 inches of gravel to each post hole, then tamp it down. The thick layer of gravel will help drain rainwater away from the base of the post and prevent wood rot. 

Mix the concrete, then pour it around the fence posts, packing it, so it’s slightly above ground level. Use your trowel to slope the concrete away from the wood to prevent water from pooling around the post. Make sure the post is plumb with your post level. 

You’ll need to build a temporary support for the post to ensure it stays plumb while it cures. Attach a scrap two-by-four to the post about a foot from the ground. Drive a wood stake into the ground about a foot away from the base of the post then attach the other end of the two-by-four to the stake. Add a second brace to the post that creates a 90-degree angle with the first brace. Give the post one more check with your post level, then leave it alone for two days to dry and cure.

With a vertical fence, the rails are responsible for holding up the pickets. While posts take over that job with a horizontal fence, the rails still serve an important purpose by adding stability. You’ll install two rails between each post, one near the top of the fence and one near the bottom. 

Nail rail hangers into the sides of the posts. Cut the top rail to length, place it in the hangers, and secure it with nails. Hold off on installing the lower rail bracket until you install most of the horizontal boards. 

While one-by-six boards are the most common lumber for a horizontal fence, you can also use one-by-four and one-by-eight boards or a combination of different sizes.

Cut your boards to the correct measurement using a chop saw or circular saw. Again, they should go from the center of one post to the center of the next. Attach the boards to the posts using hot-dipped galvanized nails or deck screws. 

As you add boards, leave at least a ⅛-inch space between each board so the wood can expand and contract. Otherwise, they’ll push against each other and buckle when absorbing moisture in humid or rainy weather. Continue working your way down from the top, using spacers between the boards to create those necessary gaps until you’re within a few inches of the ground. 

Leave a buffer of a couple of inches between the bottom board and the ground to prevent rot. Before installing the last board, attach the bottom rail bracket and rail so the lowest board on the fence conceals the rail from view.

Some of the most vulnerable parts of any wood fence are the tops of the posts. That’s because their cut ends can absorb a lot of water, leading to rot. Add post caps to each post. The caps will keep rain off your post tops while adding aesthetic flare to your fence.  

Consider adding trim to each post to give your fence a finished look. Trim consists of a board that runs up the entire post to hide the seam created by the butting ends of the fence boards. Attach the trim using nails, then use wood filler to cover the nail heads.

If you’re going to put the money and effort into erecting a horizontal fence around your property, you’ll want to take measures to ensure it stands as a testament to your fence-building prowess for as long as possible. One of the best ways to do that is by sealing your fence to defend it against rot and the sun’s harmful UV rays. 

If you’re installing a cedar or hardwood fence, seal your wood fence right away to prevent the sun from fading the color. If you’re using pressure-treated pine, you’ll need to allow the wood to dry out for a few months, so the wood will accept the sealer. 

While you can use a roller and paintbrush to apply the sealant, the job will go much faster with a paint sprayer.