How to Seal a Deck: A Comprehensive DIY Guide for Homeowners

Are you looking to protect the beauty of your deck? Read along as we take you through the process of how to seal a deck. Discover the secrets to maintain your deck!
Veda Yalamanchili
Veda Yalamanchili
Last Update:
April 9, 2024

Deck maintenance is a crucial aspect of home improvement that often goes unnoticed. A well-maintained deck enhances the aesthetic appeal of your outdoor space and increases the wood's longevity. One of the most effective ways to protect your deck from weather elements and keep it looking new is by sealing it. Sealing a deck involves various steps, including cleaning, sanding, and applying a sealer. This guide aims to provide homeowners with a comprehensive understanding of how to seal a deck, ensuring it remains an enjoyable outdoor space for years to come.

Benefits of sealing a deck

Sealing a deck goes beyond just enhancing the appearance of your outdoor space. By applying a high-quality deck sealer, you are extending the life of your wooden deck by protecting it from harsh weather conditions, UV rays, and moisture damage. This means fewer repairs and maintenance costs in the long run, saving you time and money.

Furthermore, sealing your deck can improve its safety by providing additional traction and minimizing the risk of slips and falls. With a sealed deck, you can enjoy outdoor activities with peace of mind knowing that you have taken steps to create a safer environment for yourself and your loved ones. Overall, sealing your deck is not only a smart home improvement investment but also a practical way to enhance both the beauty and functionality of your outdoor living space.

Understanding Your Deck

Before sealing or staining your deck, it is crucial to understand the type of decking material you have. Wood decks require more maintenance than composite decking, as they are prone to rot and decay if not properly protected. It is essential to inspect the condition of your deck before deciding on whether to seal or stain it, especially if it is a weathered deck.

One other thing to understand is the type of wood used during deck installation. Different types of wood require different treatment methods. For example, natural wood decks require different treatment compared to pressure-treated wood. Or, If your deck is made from a durable hardwood like cedar or redwood, it may require a different approach compared to a softwood like pine. So knowing what kind of wood your deck is made of is essential for achieving optimal results.

For a new wood deck, sealing helps protect the wood from moisture and UV damage, extending its lifespan. On the other hand, staining can enhance the natural beauty of the wood while providing some protection against the elements. Understanding these differences can help you make an informed decision on how best to care for your deck and keep it in top condition for years to come.

Preparing for Sealing a Wooden Deck


Before you begin the process of sealing your deck, it’s important to gather all the necessary tools and materials. This includes:

Safety Measures:

Cleaning Your Wooden Deck

Before you can apply a sealer, it’s crucial to ensure your deck is clean and free of any dirt, grime, or splinters. Here’s how to clean your deck:

How to Clean Your Deck

How to clean a deck
  1. Remove Debris: Start by removing any loose debris from your deck surface. This includes leaves, twigs, and dirt that may have accumulated over time.
  2. Pressure Washing: Use a pressure washer or a garden hose with a high-pressure nozzle to wash the deck. This will help remove any stubborn grime that’s stuck to the deck surface. If you’re using a power washer, be sure to keep the pressure low to avoid damaging the wood.
  3. Scrubbing: For any tough spots that the pressure washing didn’t remove, use a scrub brush to clean the area. Be sure to scrub along the wood grain to avoid causing any damage.
  4. Check for Splinters: Once the deck is clean, check for any splinters or rough spots. These can be sanded down to create a smooth surface for the sealer.

Using a Deck Cleaner

If your deck is particularly dirty or has mildew, you should use a deck cleaner. Here’s how:

  1. Apply the Cleaner: Most deck cleaners come in a concentrated form that you dilute with water. Apply the cleaner to the deck surface with a sprayer or a paint roller.
  2. Let it Soak: Allow the cleaner to soak into the wood for the amount of time specified on the product label. This gives the cleaner time to break down any dirt or mildew.
  3. Scrub and Rinse: After the cleaner has soaked, scrub the deck with a brush to remove the dirt, and then rinse the deck thoroughly with a garden hose or pressure washer.

Cleaning your deck properly not only helps the sealer adhere better but also enhances the overall appearance of your deck. Remember, a clean deck is the first step towards a beautifully sealed deck.

Sanding Your Wooden Deck

Sanding your wooden deck

Sanding is a crucial step in the deck sealing process. It not only smoothens the surface of your deck but also opens up the wood grain, allowing the sealer to penetrate deeper and adhere better. Here’s why sanding is important and how you can do it:

Importance of Sanding

Sanding your deck serves multiple purposes:

How to Sand Your Deck

Here’s a step-by-step guide on how to sand your deck:

  1. Choose the Right Sandpaper: The first step in the sanding process is to choose the right sandpaper. For most decks, a 60 to 80-grit sandpaper should be sufficient. This range provides a good balance between removing the old finish and smoothing the wood. However, if your deck is made of a softer wood, you might need finer grit to avoid damaging the surface. The goal is to remove any old finish and rough spots without creating new ones.
  2. Prepare Your Sander: If you’re using a power sander, it’s important to ensure it’s in good working condition before you start. Check the sander for any signs of damage or wear, and make sure it’s clean and free of dust. Attach the sandpaper to the sander securely, ensuring it’s flat and smooth. This will help you achieve a consistent finish.
  3. Start Sanding: Now, you’re ready to start sanding. Begin at one end of the deck and work your way to the other, sanding along the length of the deck boards. Make sure to sand all areas of the deck, including the railings and edges. Always sand in the direction of the wood grain to avoid damaging the wood. This also helps to remove any minor blemishes or stains.
  4. Clean Up: Once you’ve finished sanding, it’s time to clean up. Use a broom or a vacuum cleaner to remove the dust and debris from the deck. This is an important step because any dust left on the deck can mix with the sealer and create a rough, unattractive finish.

Remember, sanding is a crucial step in the deck sealing process. Don’t skip it if you want a smooth, durable, and effective seal on your deck.

Applying the Sealer

Applying deck sealer

Once you have all the tools and cleaned the deck, you can start the sealing process. But, before you start, protect the areas around your deck using plastic sheeting or something similar. This includes covering plants and other surfaces that you don’t want to get stained by the sealer.

Now, let’s move on to the main task - applying the sealer. Here are some step-by-step instructions:

  1. Start with the Railings: It’s always a good idea to start with the railings before moving on to the deck boards. This strategy prevents any drips or spills from the railings from landing on a freshly sealed deck, ensuring a neat and clean application process.
  2. Use the Right Technique: The technique you use to apply the sealer can significantly impact the final result. Whether you’re using a paintbrush, roller, or sprayer, make sure to apply the sealer evenly across the entire deck. An even application ensures all areas of the deck are adequately protected. Also, always follow the direction of the wood grain for the best results. This technique allows the sealer to penetrate deeper into the wood, providing a more durable and long-lasting seal.
  3. Don’t Forget the Details: While it’s easy to focus on the larger areas, don’t forget about the small details, like the spaces between deck boards. These areas are often overlooked but are just as important. Sealing these spaces helps prevent water damage and rot, extending the life of your deck.
  4. Drying Time: After you’ve applied the sealer, it’s crucial to let it dry properly. The drying time can vary based on the type of sealer used, the weather conditions, and the wood’s moisture content. Always follow the manufacturer’s instructions regarding drying time to ensure the sealer cures properly.
  5. Second Coat (Optional): Depending on the condition of your deck and the type of sealer used, a second coat might be necessary. If so, wait for the first coat to dry completely before applying the second coat. This step ensures the sealer adheres properly and provides maximum protection.

By following these steps, you can effectively seal your deck and protect it from the elements, ensuring it remains beautiful and durable for years to come.

Wooden Deck Maintenance Tips

Deck maintenance tips

Maintaining your wood deck is just as important as sealing it. Regular maintenance ensures that your deck stays in good condition and prolongs its lifespan. Here are some tips on how you can maintain your new deck or the old one that you just sealed:

Regular Deck Maintenance

  1. Keep Your Deck Dry: Water can cause damage to your deck over time. After a rain shower, sweep away the water to keep your deck dry.
  2. Use a Brightener: A deck brightener can restore the natural color of your deck and remove any discoloration caused by sun exposure or mildew.
  3. Check for Mildew: Regularly check your deck for signs of mildew, especially in shaded areas. If you find any, use a mildew cleaner to remove it.

Protecting Your Deck from the Elements

Your deck is constantly exposed to the elements, which can cause damage over time. Here’s how you can protect your deck:

  1. Shield from UV Rays: Prolonged exposure to direct sunlight can cause your deck to fade. Use a deck sealer with UV protection to shield your deck from the sun’s harmful rays.
  2. Avoid Direct Sunlight: If possible, build a pergola or install a shade sail to protect your deck from direct sunlight.
  3. Use a Preservative: A wood preservative can protect your deck from rot, decay, and insect damage. Apply a preservative after sealing your deck for added protection.

By following these maintenance tips, you can keep your deck looking its best and ensure it lasts for many years. Remember, a well-maintained deck not only looks good but also provides a safe and enjoyable outdoor space for you and your family.


In conclusion, deck sealing is an essential step in maintaining its beauty and longevity. By following the steps outlined in this article, you can protect your deck from damage caused by moisture, UV rays, and other environmental factors. Regular maintenance and resealing will help to ensure that your deck remains in top condition for years to come. Remember to choose a high-quality sealant and apply it according to the manufacturer's instructions for best results. Take the time to seal your deck properly now, and enjoy a beautiful outdoor space for many seasons ahead. 

Now that your deck is sealed, are you ready to seal your fence? Read more about sealing a wooden fence here. 

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