What is it?

Deck Sealer /
What is it?

Deck sealers are used to protect wooden decks and preserve their appearance. The barrier the deck sealer forms over the wood keeps moisture out and discourages the growth of substances such as mold or mildew. Meanwhile, its clear appearance enables the beauty of the wooden deck to shine through.


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What does it do?

What Are the Benefits of Deck Sealer?

A wooden deck can add plenty of value to your home. You can build it just outside of your home and over your yard to create a gorgeous lounge area. Building a deck close to a swimming pool or a nearby body of water also helps create more beautiful vistas around your home.

Wooden decks can be susceptible to damage though. They require diligent maintenance if you want them to retain their beauty for an extended period of time. That’s where deck sealers come in.

Deck sealers are tasked with accomplishing two things. Those two tasks are protecting the wooden deck and maintaining its appearance.

Let’s focus on the protection first. Upon applying the deck sealer, it quickly penetrates the wood and starts to form a barrier. This barrier is essential because it keeps moisture away from the wood.

Excess moisture is not good for wood. It can cause significant contraction and expansion, thus leading to the wood sustaining damage over time. The damage can manifest itself in the form of gaps and signs of buckling showing up on the wooden surface. The wood itself may also start to rot if it’s continually exposed to moisture.

Furthermore, a moist piece of wood is weaker than its dry counterpart. One wrong step onto a soaked wooden deck and you may end up with a broken panel. You can protect the wooden deck better against those potential problems by using a sealer.

What the sealer also does is hamper the growth of some unwanted organisms on your wooden deck. Of particular concern are mold and mildew.

Mold and mildew do not compromise the structural integrity of the wood, but they can cause other problems. For one, they can produce spores that trigger allergic reactions. As mold and mildew grow, they can also leave behind unsightly marks on the wood.

wet wooden deck

The good news is that sealers can stop the growth of mold and mildew on your wooden deck. Since those organisms need moisture to grow, they won’t be able to take root on your deck.

The other main benefit of applying a deck sealer is that it doesn’t change the appearance of your wooden deck. If you’ve invested heavily in building a deck from high quality wood, you probably want to showcase it. Deck sealers allow you to do exactly that.

Since deck sealers feature a clear appearance and become almost invisible after application, they don’t interfere with the look of your wooden deck. You can effectively allow the craftsmanship that went into the construction of your wooden deck to speak for itself by treating it with a sealer.

what are the types?

Should You Use an Oil-Based or Water-Based Deck Sealer?

While shopping for a deck sealer, you’ll eventually be faced with a decision. You’ll either have to choose between purchasing an oil-based sealer or a water-based product.

Both products have their advantages and disadvantages, so you need to choose carefully if you want to get the best option for your deck. Consider the following factors below when making your decision.


Generally speaking, both oil-based and water-based deck sealers are now capable of lasting for a long time. Not too long ago, the oil-based variants had a clearer edge in terms of longevity, but that’s changed with the arrival of new water-based sealers.

Still, there’s an argument for using an oil-based sealer depending on where you live. In areas where the temperatures can reach extreme levels, a water-based sealer is more susceptible to being damaged. Oil-based sealers are not as vulnerable to those extreme temperatures.

Compatibility with the Environment

Using environmentally friendly products is always a good idea. Water-based sealers would be the better choice in that regard. They contain fewer hazardous compounds and are generally safer to use around homes and yards.


How user-friendly a specific product is should be an important consideration for inexperienced DIYers. Both oil-based and water-based sealers can be regarded as the more user-friendly option depending on what matters most to you.

If you’re more worried about even application and ensuring that just the right amount of sealer is present on the deck, then the oil-based products are for you. Once they hit the surface, it’s easy to smooth them out and accomplish even distribution.

That said, getting the deck ready for an oil-based sealer can take more time because it won’t be as effective if the surface has even a small amount of moisture. In contrast, water-based sealers can work fine even if the surface is still somewhat damp.

In terms of maintenance, it’s also easier to vouch for the water-based products because they can be washed easily with soap. You’ll need special products if you want to clean an oil-based sealer.


Though both types of sealers excel at showing off the beauty of the wooden deck, they do accomplish that in slightly different ways. Water-based sealers are more about emphasizing the rich color of the wood. The oil-based sealers are better for giving the deck a nice shine that complements the appearance of the wood used.


You cannot ignore prices when shopping for deck sealers. Oil-based sealers have a definite advantage here. They are significantly cheaper than their water-based counterparts and stand out as more cost-effective options if you have plenty of surface area to cover.


Frequently Asked Questions

How Do Deck Sealers and Deck Stains Differ from One Another?

Whereas deck sealers are more focused on protecting the wood without altering its appearance, deck stains have no qualms about changing the surface’s color. Deck stains are even sold in different colors in order to allow homeowners to pick the best choice for their home.

Deck stains also have an edge over sealers because they offer better protection against UV rays. The presence of pigmentation inside deck stains is responsible for creating that protective barrier.

How Long is a Deck Sealer Expected to Last?

As noted earlier, the longevity of your deck sealer can be affected by where you live and which type you’re using. In places where temperatures can get extreme, oil-based sealers have a better chance of holding up.

Even then, the sealer you applied will probably be effective for about a year. It’s a good idea to apply a new coat of sealer once a year has passed.

How Many Coats of Deck Sealer Need to Be Applied?

You can find deck sealers that provide more than adequate protection even with a single coat. Prioritize those as much as possible. If you cannot find that type of deck sealer, you will probably have to apply two coats to ensure that the wooden surface is protected.

What Are the Limitations of Deck Sealers?

You’re banking on the deck sealer not to change the appearance of the wood so counting its neutral look as a disadvantage would be unfair. The real blind spot for deck sealers is that they struggle to protect against the harsh UV rays coming from the sun.

Because deck sealers feature no pigmentation, they don’t offer much in the way of resistance against UV rays. Over time, those UV rays can start to take the sheen off your wooden deck and even distort its appearance.

One potential solution would be to use deck sealers that offer UV protection. However, it’s important to point out that even those products cannot shield your deck completely from the powerful rays of the sun. They can slow down the warping and the fading, but the damage will still get through.

What's next?

Now that you know what deck sealer is and what type you need for the job your working on.  It's time to choose a product.