How to Build a Shadow Box Fence in 8 Detailed Steps

Grab an extra set of hands and get to work mapping out the fence in your yard. Drive a stake in at each fence corner location using a mallet, then add a few stakes intermittently along the fence perimeter. 

Have a helper hold a spool of line string while you extend it from one stake to the next, pulling it taught and looping it once around each stake as you go. 

Next, mark your post holes using spray paint. Begin with the corner posts and then move along the fence line from there. Add a post at intervals that match the width of your shadowbox panels. If your plan calls for 8-foot-wide panels, then your posts should measure 8 feet apart on center. Be precise with your hole locations, and mark each spot with a large “X” so it remains visible as a point of reference while you’re digging. 

While an 8-foot distance between each post is fine, you can go with a shorter span to produce a sturdier fence. If you opt for the shorter distance, remember you’ll need to purchase more posts. You’ll also be digging more holes and mixing more cement.

Depending on how large your fence is, you’ll likely be doing a lot of digging. A 165-foot fence with 8-foot-wide panels will have around 20 posts. While you can certainly dig all those holes with a post-hole digger and a shovel, you’ll save time and effort (and a post-project trip to the chiropractor) by springing for a gas-powered auger rental, which costs about $90 a day. 

Whether you choose a shovel or an auger, dig to the right depth and diameter. A good rule of thumb is to dig to a depth that’s one-third the height of the fence. So, if your fence is 6 feet tall, your hole should be 2 feet deep. Since you’ll add 6 inches of gravel at the bottom of each hole for drainage, you’ll need to dig to a depth of 30 inches. 

Make the diameter of each hole between 10 and 12 inches, which will allow you to add enough concrete to create a sturdy base for each post. 

While digging those holes, soak the bottom 2 feet of the posts in a sealant that contains copper naphthenate. You can accomplish this by standing up the posts in a bucket of sealer three or four at a time for about an hour. It’s extra work, but it will help prevent the parts of the fence posts that are underground from rotting.

Begin by filling each hole with a 6-inch layer of gravel, which will help drain water away from the post and prevent wood rot.

After mixing the concrete, place each post in the ground and have someone hold the post plumb while you pour in the concrete. Add concrete until it’s about 4 inches below ground level. Don’t fill the entire hole with concrete, or it will be visible after you're done with the fence installation. 

You can’t count on the posts to stand up perfectly straight while the cement dries, so you’ll need to create braces for them. Nail two pieces of scrap one-by-twos about a third of the way up the sides of the post so that they extend diagonally to the ground about 1 foot or so from the post’s base. 

After positioning the braces, check once more to ensure the post is plumb before moving on to the next hole. While this process can seem tedious, especially if you're installing a lot of posts, you’ll be happy you took the extra time to make sure each one is standing up straight when it’s time to install the fence panels. After the cement is dry, pack soil into each hole until it’s level with the ground.

You’ll install three rails (also called stringers) that run from post to post to support the fence pickets. If you’re building a 6-foot-high fence, mark the location for the first stringer 10 inches off the ground, the second one 33 inches off the ground, and the third one 56 inches off the ground on each post.

To make the process go faster, mark these measurements on a one-by-two, then use it to transfer the measurements onto each post.

Install each two-by-four stringer horizontally so that both sides of the rail are flush with the outside face of the posts. Have your helper hold up one end of the rail while you fasten the other using two 3 1/2-inch wood screws and your power driver. Hold each screw at a 30-degree angle so that the screw goes through the rail and into the post.

With the rails in place, it’s time to make your fence look like a fence by installing the pickets. 

Start at one corner of the fence. Place a 2-inch-thick block of wood on the ground under the location of the first picket. The block will serve as a spacer and buffer. If the pickets come into contact with soil, they’ll be much more likely to rot.

Place your first picket on the spacer block and against the rails. Check that the picket is level and plumb, then attach it using either two nails or screws at each of the three rail locations. 

Before you install the next picket, you’ll need to create a simple jig that will act as a spacer. Make the jig by nailing a scrap piece of wood to the back of a two-by-four. Hang the jig from the top rail of the fence using the piece of wood you nailed to it. Slide the jig against the first picket you installed, then slide the new picket up against the jig and attach it. 

Continue this process as you move down the length of the fence for perfect 3 1/2-inch spacing between each picket.

After completing one side of the fence, move to the other side. Starting at one of the fence corners, center the first picket over the gap created by the pickets you already installed on the other side of the fence and attach it with fasteners. Use your jig to install the remaining pickets as you did with the first side.

Given the time and effort you put into installing your fence, you’ll want to go the extra mile to protect it from the elements by staining and sealing it.

When you can stain and seal your fence depends on the material. If you chose cedar or redwood, stain the fence right away to preserve its rich deep red color. If you went with pressure-treated pine, you’ll have to wait about two months for the wood to dry out before it will accept stain and sealer. 

After sealing your fence, add post caps to the fence posts or cut off each fence post top at an angle with a reciprocating saw to prevent rain from collecting on the cut ends and soaking into the wood.