How to Replace a Deck Board

Kamron Sanders
·5 min read

Wood decks see a lot of wear and tear over the years. Sun damage, rot, and wear from general use can cause wood to decay and split, posing safety risks and creating visual eyesores. Luckily, you don't have to build an entirely new deck just to repair a small section of damage.

While significant damage might justify a total overhaul, many issues can be remedied by simply replacing the boards in question. This patching method can save you significant time and money and, if done properly, you'll hardly even be able to tell the new wood from the old. Follow the steps below to learn how to replace damaged deck boards and get back to enjoying your outdoor space.

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When to Replace a Deck Board

The thing you need to consider when determining whether your deck should be patched or fully replaced is the scope of the damage. Is the damage limited to just a few boards? If so, there's no question that patching is the best route. However, keep in mind that the full scope of the damage can be hidden by the deck boards, so it's incredibly important to take a look beneath to inspect the health of the joists.

Oftentimes, damage on the surface is indicative of damage beneath the surface. If deck boards are rotting in a specific spot, there's a good chance that the joists beneath them are rotting as well. This shouldn't be cause for more concern, as most damaged joists can easily be patched as well.

How to Choose a Replacement Board

Choosing wood for your deck patch is as simple as measuring the existing boards and buying boards that match those measurements. Most decks are constructed using 5/4 boards, which are 1-1/4 inches thick. The tricky part can be matching the wood species, which will greatly improve your chances of matching the look of the existing boards.

While decks can be made from a wide variety of woods, most are constructed using cedar, redwood, or pressure-treated yellow pine. To aid in finding replacement boards that match, cut a piece from the boards you're replacing and take them with you to the lumberyard or hardware store. Match the looks and smell with the boards you're purchasing. If you're not confident in your ability to do this, ask for a worker to assist you to ensure you get the right deck boards.

Bob Stefko

How to Replace a Deck Board

Follow along with these quick and easy steps to learn how to replace damaged deck boards with sturdy new ones.

What You'll Need

  • Deck boards

  • Pressure-treated 2x4s

  • Tape measure

  • Speed square

  • Pencil

  • Jigsaw

  • Thin jigsaw blade

  • Drill

  • Drill bits

  • Galvanized 16d nails or 3" exterior framing screws

  • 2-1/2" deck screws

  • Hammer

  • Cat's paw

  • Deck stain and sealant

Step 1: Assess the Damage

Before you begin ripping up the damaged deck boards, familiarize yourself with the full scope of the damage. If you see damage on the top of the deck, look for damage beneath the deck. Compromised joists will need to be structuralized as part of the repair.

If the joist has minimal damage, you can often get by with a section of joist material sistered to the damaged joist. Just be sure to secure the sistered joist to a portion of solid wood at least 1 foot past the damaged area using 16d nails or 3-inch exterior framing screws. If the joist is significantly damaged, you might need to sister the joist across its entire length.

Warning: If your joists are significantly damaged, consult a licensed contractor before moving forward with your repair.

Step 2: Plan Your Cuts

Start by using a speed square to mark the board flush alongside the joist. To find the joist, simply look through the cracks between the boards. Repeat the marking process on the other end of the damaged board section, making sure you leave at least one healthy joist between the ends you're cutting.

Step 3: Cut Out Damaged Boards

Carefully cut the damaged boards from the deck using a jigsaw. Hold the jigsaw straight and refrain from cutting into the joist below.

Step 4: Remove Boards

Remove the damaged section. If the board is nailed to the healthy joist and is difficult to remove, use a tool called a cat's paw to dig into the wood and remove the nails.

Step 5: Add Support Cleats

The ends of the new boards will be supported by cleats on each joist. To add these cleats, cut a 2x4 to at least 1 foot in length and nail or screw it into the joist just below the removed board. Repeat on the other end of the removed section. To prevent splitting, drill pilot holes using a drill bit slightly smaller than your fastener.

Tip: While the joist is exposed, seal any damaged or unsealed areas to protect from future rot.

Step 6: Measure and Cut Replacement Boards

Measure the length of the removed section and cut a replacement deck board to this length.

Step 7: Install Replacement Boards

Slide the replacement deck board into place and secure it using 2-1/2-inch deck screws. Position the board with any obvious cupping facing upward, so the board sheds water rather than holding it. If you see no obvious cupping, inspect the end grain and aim any obvious curvature upward.

Step 8: Stain and Seal the New Boards

Stain and seal the new boards to match your existing boards. For the best results, sand, stain, and seal your entire deck after installing the replacement boards.

Related: The 9 Best Deck Stains to Protect and Revive Your Deck

How to Prevent Future Deck Damage

Now that you've completed your deck repair, it's important to perform the proper maintenance to prevent future damage. Stain and seal your deck annually or biannually for the best protection. Additionally, look for reasons that your deck was damaged in the first place. Are there gutters draining on your deck or leaky spigots? Resolve any issues to ensure your deck last for years to come.