How to Seal Your Deck & Best Deck Sealers

The surface of your wooden deck can be damaged by extreme heat and cold if it doesn't have a protective coating. Sealing and staining are both ways to protect and keep your deck in good shape, but sealing has some benefits that staining doesn't.


Deck Sealer

Deck sealer is usually a clear coat that soaks deep into the wood and forms a clear film on the surface while keeping the natural look of the wood. By getting into the wood, the sealer makes a protective layer that helps keep water out and keeps moisture from getting in. Fungal growth and wood rot can both shorten the life of your deck, so it's important to use this protective finish. Deck sealer slows down the damage caused by water, but it doesn't do a good job of protecting against UV rays. Even with a sealer, direct sunlight will eventually dry out the natural oils in the wood, which will cause it to fade and crack and split.


Read more: How to Avoid, Prevent and Repair Deck Joists Rot


Deck Stain

Deck stain also makes the wood resistant to water, and it can add color to the wood in different ways, from being semi-transparent to solid. Also, many stains come in many different colors, so you can get a wide range of colors when you're done. Since stains have color added, they are better at blocking UV light and offer more protection than a sealer alone. In fact, the darker the stain, the more pigment is added, which protects your deck even more.


Applying Deck Sealer to a Wood Deck

To get the best seal possible, make sure your deck is clean before you put on the sealer. Make sure to get rid of all the dirt, dust, grime, and mildew. Check out our step-by-step guide to learn how to clean or pressure wash a deck the best way.

Before we talk about how to seal a wood deck step by step, there are a few things to keep in mind. First of all, don't put deck sealer on in direct sunlight, because the finish will dry too fast. The sealant needs time to soak into the wood well. Also, if you have a brand-new deck made of treated wood, you should wait a few weeks to stain it. This will give the wood time to dry out completely, which will help the stain soak in better. You're now ready to start!

Step 1: Check the forecast

Make sure you have at least two days of dry weather with temperatures between 50 and 90 °F before you start to seal your deck. This will make sure that the best seal is made.

Step 2: Clear the deck

Probably goes without saying, but you don't want to start sealing your deck with furniture, plants, and other items all over the place.

Step 3: Sand (if needed)

You may need to sand your deck before sealing it to make sure the sealer gets into the wood well. Sanding takes time, but it is often necessary. You can speed up the process by using a pole or palm sander, but make sure to sand in the direction of the wood's grain. When you sand, always wear a safety mask so you don't breathe in sawdust.

Step 4: Remove debris

After sanding, you'll want to make sure there are no loose pieces of wood on the whole deck. That means cleaning between the cracks and making sure the deck is completely dry.

Step 5: Stir sealer

Make sure to stir the sealer before you use it. DO NOT shake. If you shake the finish, bubbles may form.

Step 6: Apply sealer

Use a paintbrush, roller, or sprayer to spread a thin coat of paint over two to three boards. You can always add another thin coat later, as it will go on and dry better than one thick coat.

To make the best coat possible, back-rolling may also be needed. For this, you need one person to put on the seal and another to use a roller or broom to spread out puddles and work the finish into the wood well.

Step 7: Repeat & fine tune

Step 6 must be done for the whole deck. Use a finer paintbrush to apply the sealer to cracks, railings, and steps, which are hard to reach.

Step 8: Let it dry

Before using the deck, let it dry completely.

Best Deck Sealers

Protecting your deck is much cheaper than building a new one, so don't leave it out in the weather, which will cause it to wear down, rot, and grow mildew. To make your deck last longer, take action early and often with good deck stains and sealers.

But how do you know which deck stains and sealants are the best? Which ones can you count on to stand up to the weather and everyday use? Some of the best deck sealers on the market are listed below:

Thompsons Waterseal Advanced Natural Wood Protector

Thompsons is one of the best water seals on the market, so it will protect your deck from mildew and water damage. It will also help prevent long-term UV damage and color fading.

ECO-SAFE Wood Treatment – Stain & Preservation by Tall Earth

Tall Earth's ECO-SAFE Wood Treatment is great because, as long as your deck is clean, it can be used right away without any special preparation. You only need one coat to protect yourself; you don't need to put on more than one.

Rust-Oleum Coppercoat Wood Preservative

This EPA-approved deck sealer has all the benefits of a good sealer and also keeps termites and ants away from your deck. After you put it on, you might see a thin, clear green layer, but it will go away over time.

CabotStain Australian Timber Oil Penetrating Oil

CabotStain is a high-quality sealer that will go deep into even the hardest types of wood. Unlike most other sealers, it has iron oxide pigmentation that can help protect wood from UV damage.

Thompsons Waterseal – Transparent Stain

This deck stain and sealer combo is the best of both worlds. It gives the deck a transparent color and makes the surface waterproof to protect it from mildew, rot, and mold. It is easy to use and dries quickly after being applied.

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