How to Build a Deck Gate

Wooden decks have become a staple accessory on homes from coast to coast and for good reason. They’re a relatively inexpensive way to add usable square footage to the exterior of your home and can easily be built at a variety of heights to accommodate any home’s elevation. Because of this, decks often feature stairs that can sometimes be pretty high off the ground. For this reason, many homeowners opt for a deck gate to block access to the stairs.

Whether you want to ensure your children and pets stay safe while playing on the deck or simply want to keep them from wandering away, a DIY deck gate is the perfect solution. Not only is this easy-to-build gate the cherry on top of a beautiful wood deck, but it will give you the peace of mind you need to truly enjoy your deck with your family, friends, and pets. With the right tools, beginner DIYers and experts alike can easily tackle this project, but it’s important to heed the local building codes to guarantee the safety of your gate.

Before You Begin

Before purchasing your supplies, head out to your deck and thoroughly inspect the existing wood components. Are the boards and railings sound? If not, do whatever it takes to get the deck up to snuff before continuing. Tighten loose boards, replace rotting wood, and snug up screws. Even the safest, best-built deck gate will fail if attached to an already failing deck. While you’re at it, plan on resealing the deck if it’s in need of a seal coat.

While measuring the deck’s opening, use a level to check the posts on each side for plumb. If the posts are slightly out of plumb, take this into account and mount the gate and hinges accordingly. If the posts are dramatically out of plumb, this may require replacing or repairing the posts before attaching a gate.

Check Your Local Building Codes

Once you’ve measured your deck’s opening to create your supplies list, please take a look at the building codes to ensure you’re following them.

Here are the specifications you should follow:

Minimum gate height: 42 inches
Maximum baluster spacing: 4 inches
Maximum height from deck floor when closed: 4 inches
Must open into deck rather than out
Must be secured to top and bottom rails with strap hinges
Self-latching clasps must be a minimum of 3 inches from the top of the gate

Always check with your specific local building codes before moving forward with the construction of your gate.

Safety Considerations

For most DIY enthusiasts, the process of building a deck gate isn’t too intimidating. In fact, experienced DIYers could likely design and build a deck gate with little effort. However, it’s very important to pay attention to building codes when adding improvements to your home.

The building codes are in place to ensure the safety of your deck for you, your family, your pets, and your guests. Failing to build your gate according to code will not only result in marks on a future home inspection, but it will also jeopardize the safety of the gate. Follow the steps carefully and only make modifications if they stay within the bounds of the building code.

While a properly built deck gate will undoubtedly make your deck a safer place for kids and pets to play. However, once your deck gate is installed, small children still shouldn’t play on a deck without adult supervision.

Equipment / Tools

Miter saw or circular saw
Tape measure
Pencil
Speed square
Level
Drill
Drill bits
Staining or painting supplies
Orbital sander

Materials

2×4 x 8-foot pressure treated pine boards
2×2 x 8-foot pressure treated pine boards
2-1/2-inch self-drilling exterior wood screws
1-1/4-inch self-drilling exterior wood screws
2 Gate strap hinges
Self-latching gate clasp
1/4-inch x 1-1/4-inch lag bolts (optional)
1/4-inch washers (optional)
All-in-one staining deck sealant or exterior latex paint
120-grit sanding pads
Scrap wood

This deck gate design is based on a standard wood deck following building codes. Aside from the parameters set by the code, the specific lengths and heights may be different on your deck. Pay close attention to the instructions and modify these measurements as needed. Additionally, the materials list presented above is a rough guide and should be modified to suit your needs.

Acclimate the Wood

Newly purchased pressure-treated boards can sometimes have a high moisture content. This wood will be extra heavy and can even feel wet to the touch. To avoid warping and shrinking after construction, allow the wood to acclimate in a dry, shaded area for at least 72 hours before using for your project.
Cut the Gate Rails

The gate rails are the horizontal support boards on the top and bottom of the gate. The length of these will be determined by the width of your opening. Once you find that width, subtract one inch to account for hardware and clearance, then use a miter saw or circular saw to cut a 2×4 into two pieces matching the length you come up with.
Cut the Gate Posts

Cut two gate posts from another 2×4 board. The gate posts are the vertical members at each end of the gate. Their length will be determined by your desired height for the gate, with a minimum height of 42 inches and a maximum distance of four inches from the deck surface. So, a 42-inch tall gate that sits four inches from the deck surface will require two 38-inch posts.
Build the Frame

Assemble the frame by screwing the rails to the posts. To do this, place the posts on your work surface side by side. Stack a rail at the top and a rail at the bottom, then adjust until the corners meet. Screw through the rails into the posts with 2-1/2-inch self-drilling exterior wood screws, checking for square as you go. Each corner should have at least two equally spaced screws.

Warning

One of the easiest ways to compromise the strength and structural integrity of a deck gate is to use the wrong fasteners or simply not enough of the right fasteners. While one screw will create a tight hold in a wood joint, gates are stressed from all different directions once mounted. It’s better to overdo it than to risk failure of the gate later on.
Measure for the Balusters

Now that the gate’s frame is assembled, you can measure for the balusters. Since the building code specifies a maximum distance of four inches between balusters, we’ll use this number as our guide. Measure the space between each post and use this to determine how many balusters you’ll need if you space them four inches apart.
Cut the Balusters

Once you determine how many balusters you need, cut 2×2 boards to the same length as your gate’s posts. On one end of each baluster, cut a 45-degree angle. This will create a more finished look and help the balusters shed water, protecting the delicate end grain.
Fasten the Balusters to the Frame

Flip the gate so that the post side is facing upward and arrange your balusters accordingly to mockup the spacing. Begin attaching the balusters angled-side-up using 2-1/2-inch self-drilling exterior wood screws.

If your gate’s width doesn’t allow for an even amount of balusters, start in the center and work outward toward each side.

Tip

For quick and easy spacing, cut a scrap piece of wood to the length of your desired baluster spacing. Place the board between balusters as you fasten them.
Sand All Surfaces

Use an orbital sander fitted with 120-grit paper to sand all surfaces until smooth, removing all splinters and rough edges.
Set the Gate in Place

This step will be easier with a helping hand to hold the gate in place. However, even with a helping hand, perfectly fastening the gate to the deck can be difficult. To make accurate installment a simpler process, we recommend mocking up the positioning before attaching the hinges.

To do this, cut and stack scrap boards to the exact height you wish for the gate to sit above the deck (we decided on four inches in step two). Place the stacked scrap boards next to each deck post and place the gate on top. Adjust the gate until it sits exactly where you want it.
Attach the Hinges

Starting at the top, place the open strap hinge so that one side hits the gate rail and the other hits the deck post, with the hinge point positioned in the void between the rails. Use a small level to ensure the strap is leveled, then fasten using the included hardware.

If no hardware is included with your hinges, use 1/4-inch by 1-1/4-inch lag bolts fitted with washers. Mark the hinge’s position and drill pilot holes before securing.

Repeat on the bottom hinge.
Attach the Self-Latching Gate Clasp

On the side opposite the hinges, attach a self-latching gate clasp using 1-1/4-inch self-drilling exterior wood screws. In accordance with the building code, place the clasp a minimum of three inches from the top of the gate.

Tip

Adding a wooden stopper to the post where the clasp is located will take stress off of the clasp and strengthen the gate when in the closed position. To add this, start with the gate in the closed position. Cut a small piece of wood, screw it to the post outside of the gate, and flush against the front of the gate. For added strength, add a top and bottom stopper. This addition will help prevent the clasp from wearing and falling out when the gate is slammed or blown shut by strong wind.

How to Seal or Paint a Deck Gate

While pressure-treated boards are indeed intended for exterior use, their lifespan will be cut short without proper sealing or painting. Eventually, moisture and sun damage will compromise the strength of the boards.

Pressure-treated decks need to acclimate outside for at least 30 days before they’re sealed. Whether you just need to seal your new gate or are resealing your entire deck in the process, wait at least 30 days after you install the gate before sealing. Failure to do so will result in poor penetration by the sealant.

Love the look of a painted gate? No problem. Contrary to popular belief, pressure-treated wood can be painted, you just have to follow the proper steps for painting pressure-treated wood. If painting, this acclimation process is even more important, as painting pressure-treated wood before it has fully dried and acclimated will result in bubbling paint.

Ways to Dress Up a Basic Deck Gate

To take your deck gate to the next level, consider adding a few visual upgrades. As long as you refrain from making changes that go against the building code, you can swap out the balusters for black metal balusters for a little contrast, add lattice over top of the balusters, or even add a diagonal support piece across the balusters to give your gate a farmhouse aesthetic.

If you wish to miter the frame to give your gate a more custom-built look, this is definitely a viable alteration. We recommend adding corner braces on the inside corners of the frame to further strengthen the gate.

When to Call a Professional

If you’re at all concerned about the structural integrity of your deck or deck gate, it’s wise to consult with a professional to ensure you, your family, your pets, and guests stay safe. A carpenter will be able to inspect the deck and make any necessary repairs to compromised materials.

When to Replace a Deck Gate

If properly sealed as needed, a well-built deck gate should last for years to come. However, if you notice rot, loose hardware, or otherwise failing components, these issues should be addressed immediately. In many cases, failing components can be repaired or replaced without replacing the entire gate. If at any point you notice the deck components surrounding the gate failing, address these issues immediately.