How to Build a Deck Gate in 11 Steps

You’ll need to figure out what size you want the gate to be. Most gates will be about 36 to 48 inches wide. Measure the space where you plan to install a deck gate with the measurements required by local deck codes in mind.

• Measure the width at the bottom, middle, and top of where the gate will be.

• Account for a 1/2 to 3/4-inch gap on each side of where the gate will be, so it can open and close easily.

• Measure how tall you’d like the gate to be.

• Use a level on the deck surface and rail posts to adjust for any slight variations.

• Write down all of your measurements, and keep that information handy when you shop for supplies.

Failing to plan is planning to fail for any project. Before you start sawing into your wood planks, draw some sketches of the gate. You may also want to use a template you can find online to guide how your gate will look as you build it.

Whether you use a template or your sketches, write out the measurements of each piece and show how they will connect to form the gate. Make note of essential gaps, including each side of the gate and the bottom of the gate, in your diagram.

Most deck gates consist of pressure-treated wood, thanks to its resistance to rot and pest damage. With the right care, pressure-treated wood can last up to 40 years. But pressure-treated wood typically has a high moisture content and needs to acclimate to its surroundings before you can build with it. Otherwise, the wood may warp after you’ve built the gate.

Lay the wood out on a tarp or dry area with plenty of shade. Let it rest for at least 72 hours before proceeding.

Gate rails run horizontally at the top and bottom of the gate. You’ll want to turn to your measurements and gate diagram when it’s time to cut the rails.

Subtract about 1 inch from the measurement of the width of the gate opening. This will leave space for gaps and hardware. Cut a two-by-four wood plank into two pieces to match your measurements with a miter or circular saw.

The gate posts run vertically on each end of the gate, and along with the gate rails, establish the perimeter of the gate you’re building. Making the gate posts is similar to cutting wood for the gate rails.

Review your height measurements for the gate, which will be at least 42 inches tall but no more than 4 inches off of the surface of the deck. Use the miter or circular saw to cut another two-by-four according to your height measurements.

Now, it’s time to join the gate posts and rails to form the deck gate frame. First, you’ll use a miter saw to cut opposing 45-degree angles, so the rails and posts fit snugly when you screw them together.

Arrange the posts side by side, then lay the rails toward the top and bottom of the posts. The arranged wood will resemble a picture frame. Push the posts and rails together until the opposing 45-degree angled ends come together. Use a drill to screw 2-1/2-inch self-drilling exterior wood screws through the rails and into the posts.

Use at least two screws spaced equally apart for each corner of the gate. Feel free to use additional screws with equal spacing in each corner to help the gate better withstand wear and tear over time.

Balusters will fill out the center area of the gate. Space these out no more than 4 inches apart to prevent children or pets from slipping through. Determine the number of balusters you’ll need, keeping spacing requirements in mind.

Cut two-by-two pressure-treated wood boards to the same height as the gate posts with a miter or circular saw. At one end of each baluster, you can use your miter saw to cut a 45-degree angle to help the wood shed water. This is optional, though, and you can choose to leave squared ends.

Using a wood block cut to the desired spacing measurement as a guide, lay the spacer flush with one gate post. Lay the first baluster flush on the other side of the wood spacer, then use a drill and 2-1/2-inch self-drilling exterior wood screws to attach the baluster to the top and bottom rail.

Move the spacer to the opposite side of the baluster, making sure it’s flush. Then lay the next baluster and repeat until all balusters are attached.

The gate is now ready for some cosmetic upgrades and a few final touches. Sand down all surfaces of the gate with 120-grit sandpaper. You can use an orbital sander or manually sand until you have a smooth finish. 

After sanding, you can paint, stain, or seal the gate to match the style of your deck. Make sure to let the finish dry before you finish building and installing the deck gate, or you could be left with visible drips or streaks.

Cut more scrap boards to the desired height—but no more than 4 inches—where you want the gate to sit off of the deck’s floor. Lay the scrap boards across the deck floor to help you position the deck gate into place for installation. (Alternatively, you can save yourself some sawing by asking for a friend to help you hold the gate in place.)

With the gate positioned into place, use a drill and the screws included with your hardware to attach the hinges to each gate rail and the deck post.

On the opposite side of the gate from the hinges, mark a spot a least 3 inches from the top of the gate to install the gate latch. Use the screws from the hardware or 1-1/4-inch self-drilling exterior wood screws to secure the gate latch in place.