Make a payment on the website. We accept payment plans through Payfirma.

How to Replace Rotted Deck Boards: DIY Guide on How to Fix Rotting Deck



Table of Contents

Ready To Start Your Project?

Absolute Home Services is here to help! Whether you're in need of expert landscaping, handyman services, deck and fence work, or painting, our team has the skills and experience to get the job done right. Don't wait any longer to start creating the home you've always wanted.

A well-maintained deck enhances both the beauty and functionality of your home, offering a versatile space for relaxation and entertainment. However, if your deck is suffering from rot, it can quickly become an unsightly safety hazard. With this guide, you'll gain the knowledge and confidence to replace those damaged boards yourself and restore your deck to its former glory.

At Absolute Home Services, we specialize in a wide range of renovation services, including comprehensive deck and fence services. Our team possesses in-depth knowledge of all aspects of wood decking and can expertly handle deck and fence installation, renovation, and maintenance.

We're eager to share our expertise to help you tackle any rot-related issues you may be facing. Follow our step-by-step instructions to ensure your deck is not only safe but also a source of pride and enjoyment for years to come.

Why Your Deck Might Be Rotting: Understanding the Causes of Decay

Even the sturdiest wood decks are susceptible to rot over time. The main culprit is prolonged exposure to moisture, which creates an ideal breeding ground for fungi like mold and mildew. These organisms thrive in damp environments and can rapidly break down wood fibers.

Several factors contribute to excessive moisture buildup on your deck:

  • Lack of protection: Unsealed or untreated wood, as well as decks with worn-out stains or sealers, are more likely to absorb moisture.
  • Poor drainage: When water pools on your deck or doesn't drain properly, it can saturate the wood and promote rot.
  • Improper flashing: Incorrectly installed flashing, particularly where the deck meets your house, can allow water to seep into the structure.
  • Ground contact: Decks built too close to the ground or near bodies of water are at a higher risk of rot due to increased moisture exposure.

Dry rot: This particularly destructive form of rot is caused by fungi that feed on the cellulose in wood, leaving it brittle and weak. Dry rot can spread rapidly and is especially concerning because it can continue to thrive even without a constant source of moisture. Once established, it can generate its own moisture, quickly weakening the entire deck structure and potentially spreading to your home.

Recognizing the Signs of Decay

Vigilance is key when it comes to protecting your deck from rot.

Keep a watchful eye out for these telltale signs:

  • Discoloration: Look for unusual patches of gray, white, or dark spots on the surface of your decking boards.
  • Soft or spongy texture: Gently press on the wood in various areas. If it feels unusually soft or gives way easily under pressure, rot may be present.
  • Cracks and splinters: As rot weakens the wood fibers, boards become more prone to cracking and splintering.
  • Musty odor: Decaying wood can sometimes emit a distinct, musty smell.
  • Insect activity: Termites and other wood-boring insects are drawn to decaying wood, so signs of infestation could indicate underlying rot.

Remember, consistent deck maintenance and early detection are keys to keeping your decking intact and saving on repair!

Recognizing the Signs of Decay

Deciding When to Repair or Replace a Rotting Deck

The extent of the damage will determine whether a simple repair or a full deck replacement is necessary. If you detect rot early and only a small area of a board is affected, you might be able to patch it. However, if multiple boards are compromised or the rot has reached the deck's support structure, replacement is the safest course of action.

Material matters: Wood deck boards generally require replacement more frequently than composite decking, which is naturally resistant to rot.

Choosing Replacement Boards

Choose the same type of wood or a compatible material as your existing decking boards.

  • Pressure-treated wood: This is the most common and budget-friendly choice, offering adequate protection against rot and decay.
  • Composite decking: While more expensive, composite decking boasts superior durability and rot resistance, making it a worthwhile investment for long-term performance.
  • Capped composite decking: This option combines the strength of composite materials with an additional protective layer for enhanced resistance to the elements and fading.

Replacing Deck Boards: A Step-by-Step Guide

Required Tools & Equipment

  • Circular saw
  • Speed square
  • Drill with driver bit
  • Pry bar (nail puller or cat's paw)
  • Hammer
  • Tape measure
  • Safety glasses
  • Work gloves

Required Materials

  • Replacement deck boards
  • 2-1/2-inch deck screws
  • 3-inch galvanized deck screws
  • Joist hangers (if needed)
  • Flashing (if needed)
  • Wood sealant or stain (optional)
Replacing Deck Boards: A Step-by-Step Guide

Step 1: Assess the Damage

Start by thoroughly examining your deck. Check the surface boards, the underlying structure (joists, beams, and posts), and the ledger board (where the deck connects to your house). Look for signs of rot: discolored or soft spots, cracks, or a spongy texture. A firm poke with a screwdriver or pry bar can help identify weak areas.

Knowing the extent of the damage will help you decide if you can get away with patching a few spots or need to replace entire boards.

Step 2: Measure and Mark

Once you've identified the problem areas, measure the damaged sections of the deck boards. Plan your cuts so the ends of the new boards will rest directly on a joist for optimal support. Use a speed square and a pencil or chalk to mark your cutting lines accurately.

Step 3: Remove the Damaged Boards

Gently pry up the damaged boards using a pry bar. If a board is being stubborn, you can score it with your circular saw to make it easier to remove.

Pro Tip: Don't put new boards directly over rotten wood. This traps moisture and invites the rot to return.

Step 4: Check the Foundation: Joists, Beams, and Posts

With the old boards removed, you have a clear view of the supporting structure beneath. Carefully examine the joists, beams, and posts for any signs of damage, such as water stains, rot, or insect activity.

Use a screwdriver or similar tool to probe for soft spots, which could indicate hidden decay. Addressing any structural issues now is essential for a safe and long-lasting deck repair.

Step 5: Reinforce with Support Cleats or Joists

Adding support cleats or joists provides extra stability for your new decking.

Here's how:

  1. Prepare the cleats/joists: Cut two 12-inch sections of 2x4 lumber. Pre-drill pilot holes to prevent splitting.
  2. Position and secure: Place the cleats or joists flush against the inside face of the exposed joists, aligning the tops. Secure them using 2-1/2-inch deck screws.

Optional: If you find loose connections or weak points in the deck frame, reinforce them with additional joist hangers.

Step 6: Install Flashing for Extra Protection

Before you lay down the new boards, take the extra step of installing flashing. This simple measure can significantly protect your deck from future moisture damage. Cut a piece of flashing tape to fit over the installed cleats.

If possible, lift the adjacent decking board and slide the flashing underneath it as well. This creates a watertight seal between the cleat and the joist, preventing water from pooling and minimizing the risk of rot.

Step 7: Measure Twice, Cut Once

For a seamless fit, carefully measure the gap left by the removed boards. Ideally, use a single board to span the distance, leaving a 1/8-inch gap at each end for drainage. Be sure to center the cuts over joists for maximum support. If replacing multiple boards, stagger the cuts in relation to neighboring boards for added structural strength.

Once you've double-checked your measurements, cut your replacement board to the exact length needed.

Step 8: Prepare and Weather the New Board

Before installing your replacement board, consider applying a stain or sealant for added protection and a more seamless appearance. Pre-treating the board allows for easier and more even coverage, helping it blend seamlessly with the rest of your deck. In fact, giving your entire deck a fresh coat of finish is a great way to achieve a cohesive look.

Step 8: Prepare and Weather the New Board

Here are some additional tips for a professional finish:

  • Match the wood: Opt for the same type of lumber for your replacement board to avoid any noticeable patches.
  • Weathering: If your existing deck has a naturally weathered patina, you can create a similar effect on your new board before installation by using a solution of baking soda and water.

Step 9: Install and Secure the Replacement Board

Carefully inspect the new board for any warping or cupping. If you notice any, position the board with the crowned side facing up when installing. This helps prevent water from pooling and reduces the risk of further cupping as the wood ages. If there's no visible warping, examine the end grain and install the board with any curvature facing upwards.

Slide the replacement board into the prepared space, ensuring a consistent 1/8-inch gap between it and the adjacent boards. This gap allows for proper drainage and prevents moisture buildup.

Pre-drill pilot holes at each end of the board, about 3/4 inch from the edge and centered over the support cleats. If the board spans multiple joists, drill additional pilot holes accordingly. Then, secure the board firmly to the cleats and joists using 3-inch deck screws.

Pro Tip: Maintain a consistent appearance by using the same type of screws and spacing as the rest of your deck. This attention to detail will give your repair a polished, professional look.

How to Prevent Future Deck Damage

A little preventative maintenance goes a long way in protecting your deck and extending its lifespan.

Here are some essential steps to keep your deck in top shape:

  • Regular cleaning: Sweep away debris and leaves to prevent moisture buildup and staining.
  • Sealing and staining: Apply a sealant or stain to your wood deck every few years to protect it from the elements and prevent rot.
  • Improved drainage: Ensure water doesn't pool on your deck by addressing any drainage issues. This might involve adjusting the slope, adding gutters, or installing drainage channels.
  • Annual inspections: Conduct a thorough inspection of your deck each year to identify any signs of wear and tear, such as loose boards, rusty fasteners, or cracking wood.
How to Prevent Future Deck Damage

The Cost of Replacing Deck Boards: DIY vs. Professional

The cost of replacing rotting deck boards can vary significantly depending on several factors, including the extent of the damage, the type of decking material you choose, and whether you opt for a DIY approach or hire a professional contractor.

The DIY Advantage: If you're only replacing a few boards or refreshing the appearance of a structurally sound deck, doing it yourself can be a cost-effective solution. You'll save on labor costs and have the satisfaction of completing the project yourself.

Contractor Costs: For more extensive repairs or replacements, hiring a contractor may be necessary. The cost of professional deck repair or replacement can range from $800 to $3,000 or more, depending on the size of your deck and the materials used.

Material Costs: The price of decking boards varies depending on the type of material:

  • Pressure-treated lumber: This is the most affordable option, but it may require more frequent maintenance.
  • Cedar: Naturally resistant to rot and decay, cedar is a more expensive but durable choice.
  • Composite boards: Although the most expensive upfront, composite decking offers exceptional durability, low maintenance, and a longer lifespan.
The Cost of Replacing Deck Boards: DIY vs. Professional

Additional Costs: Remember to factor in the cost of screws, stains, sealants, and any other necessary materials when budgeting for your deck repair or replacement project.


Replacing rotted deck boards may seem daunting, but with the right guidance and a little elbow grease, it's a project well within reach for the average DIY enthusiast.

By following our step-by-step instructions and using the right tools and materials, you can restore your deck to its former glory and create a safe, inviting outdoor space for years to come. However, we understand that not everyone has the time, tools, or inclination to tackle DIY projects.

If you prefer to leave your deck repair in the hands of experienced professionals, Absolute Home Services is here to help. As a top home improvement contractor in Canada, we specialize in a wide range of repairs and renovations, including deck restoration and replacement.

Our team of skilled craftsmen will ensure your deck is not only beautiful and functional but also built to withstand the test of time.

Don't let rotting deck boards dampen your outdoor enjoyment. Take action today and transform your deck into a space you'll be proud to show off. Whether you choose the DIY route or enlist our expert services, we're committed to helping you create a home that reflects your unique style and enhances your lifestyle. Get your free quote today!

DIY or Hire a Pro? Making the Right Choice for Your Composite Deck Project

This is a crucial decision that will impact the cost, timeline, and quality of your deck project. Here's a breakdown to help you decide.

Ready To Start Your Project?

Absolute Home Services is here to help! Whether you're in need of expert landscaping, handyman services, deck and fence work, or painting, our team has the skills and experience to get the job done right. Don't wait any longer to start creating the home you've always wanted.


No items found.