Learn how to build a horizontal wood fence in your yard with this simple DIY tutorial. Learn how to install posts and attach wood slats, spaced evenly apart, to create a custom modern-looking fence.
We installed a 3-foot-tall horizontal fence in our side yard. It’s at the top of a hill, so its purpose it to prevent people from going down the hill, not for privacy. We love the look of modern fences with the slats separated and horizontal. It looks perfect with our mid-century home. Really, though, I think horizontal fences look great with any style of home.
To be honest, this project took us years. We first took down the old, fallen-down fence back in 2015 and the chain link fence next to it. Then we realized we had 3 different types of fence posts we needed to use for our new fence and it took us a while to figure out how. Years. We just kind of ignored it for a while. Once we figured out the fence posts, we were ready to put up the wood slats. But it was post-Covid and the price of wood had sky-rocketed. So, we waited a year or two more. When we finally finished the fence, it was beautiful and it totally transformed that side of our yard.
I should also add that my husband and I built the fence together, that’s why I use “we” throughout this post. I think it might be possible to build it alone, but it would certainly be very difficult and require a lot of clamps.
Fence Posts
The posts are the backbone of a fence. They hold up the entire fence and anchor it to the ground. If you want a strong fence that will last, you need solid, sturdy posts that will stay anchored and straight and hold the weight of the fence.
If you’re starting from nothing, you’ll need to have 1/3 to 1/2 of the height of your fence posts underground to give it the required stability. So, If you want a fence that’s 3 feet tall, like ours, then you’ll need to dig a hole that’s 1 to 1.5 feet deep, and your pole should be 4 to 4.5 feet tall. Place the pole in the hole, then fill in the hole with concrete. If your posts are wood, you’ll need to make sure the concrete comes above the dirt level. Wood does not do well when it’s touching dirt. Our poles are metal, so we were able to hide the concrete with a little dirt on top.
Working with the Posts You Have
Remember we used to have two different fences in this space. One was a falling-down wood fence that had about 5 layers of peeling paint. And the other fence was a rusty chain link fence. We removed both fences but left the metal fence posts from the chain link fence. We decided to reuse the old fence posts because they were still straight and in good condition. Also, removing fence posts that have a solid concrete base is a huge pain. You often cut off the fence post instead of trying to dig up the large, and heavy, concrete anchor.
Our problem with reusing the old posts is that there were two different types of posts: round posts at the end and T posts in the middle. We also were gifted some square steel posts to use where the old wood fence had been. Since we wanted a wood fence, we needed to figure out how to attach wood to all 3 types of metal fence posts. And when we asked for help at the hardware store, the answer was, “Those are fence posts for chain link fences.” So we had to figure this out ourselves. We did it by attaching a 2×4’ to the front of each post.
Round Fence Posts
Our solution was different for each type of fence post. For the round posts, there are metal brackets made to tighten around the post and then attach to wood. Unfortunately, they are made to attach to horizontal beams, not the vertical wood posts we wanted. So, to make the wood wide enough to fit, we screwed two 2x4s together to make, essentially, a 2×8’. We screwed them together using a Kreg jig so that the joint was hidden on the inside and back.
Square Fence Posts
For the square posts, We found metal strips that we were able to bend around three sides of the posts. We used metal screws to attach the metal strips to the square post and wood screws to attach it to the 2×4.
T-Shaped Fence Posts
For the T posts, we were stumped for a while. They are obviously made to attach to a wire fence, not wood. Our solution was actually pretty easy: the square posts we had been gifted fit perfectly over the T posts. We pushed the square post into the ground as much as possible. It still wiggled just a little, but the cement anchor of the T-post kept it firmly in place.
Leveling the Fence Posts with a String
Once we had solved how to attach 2×4′ wood posts to each of our metal posts, we had to make sure all of the wood posts were the same height. The dirt was not very level, and measuring from the ground up was a good way to get a wonky fence. We needed all of the tops of the wood posts to be level. We leveled them by tying a string 1 inch below the top of the first post and threading a torpedo level onto the string. With the string pulled tight, we measured 1 inch below the second post and attached it to the metal posts, checking to make sure the string was level. We did this for all seven fence posts.
Prepping the Wood for the Fence
Since wood is a natural material, if it’s untreated, it will eventually break down and deteriorate. Just like a tree in the forest. Mother Nature turns wood back into dirt that can be used by the next generation of trees. We don’t want our fence to break down, though. So we coated the wood with a finish. We painted the fence posts on all sides with a Urethane, oil-based finish. More about that later. Then we laid out all of our fence boards and painted the top and all of the sides. The back side we left unfinished, to be painted after they were put up on the fence.
We used cedar fence boards that measure 1×8 inches and are 8 feet long. The 8 feet is because our fence posts are a little less than 8 feet apart. The 1×8 is because that’s the standard (read: cheaper) size that they come in. And cedar because cedar is a great, rot-resistant wood to use outside. Plus, it’s beautiful. However, we wanted thinner wood slats on our fence to make it more modern. So we used a table saw and ripped each board in half, so that it measure 4-inches across. Actually, 3.5 inches because wood measurement names and the actual measurements are a little different because wood shrinks when it dries.
Attaching the Fence Top Row
To start attaching the fence slats, we did the top first to make sure it was perfectly level. We clamped the end of a slat to our first post so that it covered the top of the post by about an inch. (Since it’s a modern style, we wanted the posts not to show much.) Then we held the other end of the slat up the the next post and placed a 4-foot level on top of the slat, adjusting until it was perfectly level. We had pre-drilled holes, so once it was level, we attached it to each post with two screws. Then we clamped the next board to the second post and continued.
Since we were using pre-existing fence posts, they were all slightly different distances apart. That meant we couldn’t pre-cut all the slats to the right size. Each time we would hold the slat up to the post and, using a square, draw a line across the slat at the center of the post board. We ended up with sort of an assembly line: Hold the board up to the posts, mark the length, cut the slat with the miter saw, pre-drill the holes, level the board, and screw it onto the fence post.
To pre-drill the holes, we made a jig. The jig was just a small piece of wood that we could hold onto the end of the slat that had holes already drilled in it right where we needed our screw holes to be. It was a lot easier just to hold the jig on the wood than to measure where the screw holes needed to be each time. We couldn’t just eyeball where the screws needed to be or they might be too far from the end and off the fence post or they might be too close to the end and split the wood.
That first row of slats definitely took the longest. Each slat was checked and double-checked. With the first row put on straight, the rest of the wood went up pretty quickly.
Installing the Fence Slats with Spaces
To make the spaces between each board, we needed a spacer. You can buy spacers, but it was easy and cheap to make our own. I wanted the space between each 3.5-inch board to be half an inch. So we cut three small pieces of wood half an inch wide. Each time before we put up a new slat (after the first row), I taped a spacer on the fence post below the lowest slat. Then we pushed the new slat up to the spacer and screwed it on. Easy peasy. Well, except that the spacer gets stuck sometimes if the slat is too tight. But it wasn’t hard to wedge the spacer out with a flat-head screwdriver.
Protecting the Wood
Once all of the wood slats were attached, the fence looked finished. But we still needed to coat the last side with Urethane to protect the wood. Just a note, I prefer to use an oil-based urethane instead of water-based latex to protect outdoor wood. Oil-based finishes hold up longer and resist water better. Unfortunately, it’s becoming harder and harder to find oil-based products in hardware stores. I found that Varathane makes a Spar Urethane that is oil-based.
Whatever type of finish you use, you will need to reapply the finish over time. The reason I prefer an oil-based finish is that it last longer and I can wait another year or two before I need to reapply a coat of urethane. I’ve found that water-based finishes often need to be reapplied every year when used outside. Whatever you use, make sure you use the same finish every time. You don’t want to paint latex over an oil-based finish or vice versa. It causes so many problems.
If you used wood posts that go into the ground, you might want to read my post about protecting wood from dirt. An old friend who was a contractor for decades taught us how to keep wood safe from rot and termites if it touches the dirt.
Finished Fence
I love looking outside at our beautiful fence. Every morning when I eat breakfast, my view is looking at that side year. The new, modern fence totally transformed the space. Plus, our new windows really improved my view too. Now I’m excited to start planting and landscaping that area.
