Seal the Deal: A Step-by-Step Guide on How to Seal a Deck Like a Pro!

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As a professional woodworker, I’ve worked with various types of wood over the years. There’s something undeniably beautiful about a well-maintained wood deck. It adds warmth and character to any outdoor space, making it a hub for relaxation and entertainment. 

However, maintaining that natural beauty requires diligence, and one of the essential tasks in preserving your deck is regular refinishing and sealing. In this comprehensive guide, I’ll walk you through sealing a deck, which can be broken down into two main parts: cleaning the deck and applying a sealer.

How to Seal Your Deck

1. Prepping the Deck

Before you start cleaning or sealing, removing any debris and gunk lodged between the deck boards is crucial. I recommend using screwdrivers and putty knives for this chore. It’s a small but vital step to ensure your deck’s longevity.

clean deck

Once you’ve tackled the larger debris, sweep your deck well. It might seem like a simple task, but it helps to clear away smaller particles and prepares the surface for more thorough cleaning.

Using a Deck Cleaner to Prepare the Deck

Invest in a quality deck cleaner available at your local hardware store or big box outlet to prep your deck for sealing. These cleaners are specially formulated to remove dirt, grime, and remnants of a previous sealer. Follow the manufacturer’s instructions for the best results.

Applying Deck Cleaner and Proper Techniques

Choose a cloudy day (but not rainy) to apply the deck cleaner. It prevents the sun from drying out the cleaner too quickly, ensuring it has enough time to work magic. 

You can apply the cleaner using a paint roller, a garden sprayer, or a bristle brush. Work from the bottom up to avoid spills and splatters on dry wood when dealing with wood railings and posts.

After applying the cleaner, let it sit according to the manufacturer’s instructions. Afterward, rinse thoroughly. Allowing your deck to dry completely is essential. Allot a minimum of 48 hours before moving on to the next step: applying a deck sealer.

2. Applying a Deck Sealer

Choosing a suitable deck sealer is crucial. Generally, the more opaque the sealer, the better it can withstand weather and wear. 

sealing deck

However, if you prefer a finish that lets more of the wood’s natural grain and beauty show through, opt for a lighter, more transparent sealer. Remember that clear sealers may require more frequent cleaning and resealing.

Before applying the sealer, check the weather forecast. Ideally, you’ll want a clear, two-day period with moderate temperatures between 50 and 90 degrees Fahrenheit. It will ensure the sealer has the best conditions to dry and cure effectively.

Sanding the Deck If Necessary

If your deck’s surface has any fuzzy grain raised by the cleaning process, consider sanding it to ensure the sealer penetrates the wood effectively. Use 80-grit sandpaper, and remember to sweep or vacuum the decking thoroughly when you’re done.

Applying the Sealer with a Brush, Roller, or Sprayer

Before applying the sealer, give it a good stir, but avoid shaking it. Shaking can introduce air bubbles into the finish, which you want to avoid.

You have a few options for applying the sealer: a brush, a roller, or a sprayer. Each has its advantages. While a roller is faster, a brush helps force the sealer into the wood’s open pores and grain. 

sealing deck with a sprayer

To ensure an even coat, apply the sealer to three or four boards simultaneously, working their entire length. 

3. Allowing the Deck to Dry Completely

After you’ve applied the sealer, allow your deck to dry completely. Ensuring the sealer properly cures and provides the protection your deck needs is critical.

Deck Sealer vs. Deck Stain

Deck sealer is typically a transparent coat that penetrates deep into the wood, forming a transparent film on the surface while maintaining the wood’s natural finish. 

This sealer creates a protective layer that minimizes water infiltration and locks out moisture. It reduces fungal growth and wood rot, extending your deck’s lifespan. However, the deck sealer does not offer robust protection against harsh UV rays, which can dry out the wood’s natural oils, cause fading, and lead to cracking and splitting over time.

man staining deck with Deck Stain Brush Applicator

Deck stain provides water-resistant qualities while adding pigment to the wood in varying opacities, ranging from semi-transparent to solid. Many stains offer various tones, allowing you to achieve different finished colors. 

The darker the stain, the more pigment it adds, increasing protection against UV [1] light. Deck stains are an excellent choice if you want water resistance and UV protection for your deck.


Maintaining the natural beauty of your wood deck is not just about aesthetics; it’s about preserving an essential part of your outdoor living space. Regularly cleaning and sealing your deck can significantly extend its lifespan and keep it looking stunning for years. 

Remember to choose the suitable sealer or stain for your specific needs and follow the steps outlined in this guide for a successful deck sealing project.

Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You've probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.

Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.
Robert Johnson

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