What Is the Best Sealer for Pressure Treated Wood? 

 December 14, 2021

By  Dale Keese

Pressure treated wood is an excellent choice for outdoor furniture. While pressure treating wood already provides some protection, it still requires regular sealing against moisture which can cause mildew, splitting, and warping. But with all the sealer types out there, which works best for this type of wood?

A sealer that is water-based, offers water resistance and UV protection, and is eco-friendly or has a low VOC content is best for pressure treated wood. Solid finishes are recommended for areas that have less foot traffic, while semi-transparent is best for areas of heavy foot traffic.

There are other things to consider when selecting a sealer for your pressure treated wood. Read on below to learn more.

Choosing a Pressure Treated Wood Sealer

Sealing pressure treated wood is a simple step in maintaining its aesthetic, form, and function.

The right sealer will ensure that the wood is protected from damage caused by water, moisture, and ultraviolet rays. There are dozens of different wood sealers out there, so here’s how to choose the right one for this project.

Oil or Water-Based

When shopping around for a sealer used for pressure treated wood, you’ll discover that they come in water-based or oil-based formulas. Each of them have their own advantages and disadvantages, though most homeowners tend to prefer water-based sealers. Water-based wood sealers are usually preferred because they offer superior UV resistance, don’t have a strong odor nor do they trap moisture, and they are non-flammable.

Additionally, water-based sealers can easily be reapplied if the color fades. It’s a simple process involving just washing the surface of the wood using soap and water.

The disadvantage to using water-based sealers for pressure treated wood is that: if you don’t strictly adhere to the manufacturer’s directions in applying it, you won’t get the ideal results, and it must be applied thoroughly with caution, to avoid over-application which can result in peeling.

UV Ray Protection

If your pressure-treated wood is used outdoors, a sealer that can protect from UV rays is critical. Keep in mind that there’s no product that can provide 100% protection from the sun’s harsh rays especially in the summertime, but sealing will certainly slow down the damage caused by the sun’s rays on outdoor pressure-treated wood.

Look for sealers that explicitly state they offer ultraviolet ray protection, which can be verified based on its zinc content. Zinc is the main ingredient in sealers that offers top UV ray protection.

Water Resistance

One of the main jobs of sealers on wood is to protect it from water. That’s because water is the number 1 culprit when it comes to damage especially with changes in weather and the temperature. These all lead to wood shrinking and expanding, which then result in splitting, warping, or cracking.

If you want to be sure that the sealer you chose is truly water-resistant, you can do a bead test by sprinkling some water on the wood after it has cured from sealing. If a bead forms on the surface, then it’s water resistant.


There are 4 types of finishes available among sealers for pressure-treated wood. These are solid, semi-transparent, clear, or colored.

Solid sealers are pigmented, which can change the wood’s original color. These are recommended for vertical wood projects such as siding and fences. Meanwhile, semi-transparent finishes are ideal for areas that are exposed to heavy foot traffic such as deck boards.

Clear sealers offer some degree of protection from moisture and UV rays though don’t prevent fading, and clear sealers used on wood tend to gradually turn gray. The upside is that clear finishes enhance the natural beauty when the wood is new though it will still be prone to fading and graying.

Color finishes are more pigmented and can protect better against ultraviolet rays. There are many tones of wood colors though light hues are always best since you can alter or change it in the future, while dark stains can’t be undone. Last but not least, light tones are best for pressure treated wood in projects that are exposed to heavy foot traffic since wear and tear will not be as obvious.


Go with a sealer that is low in volatile organic compounds (VOCs), which are harmful to inhale and are also toxic to the environment, children, pets, and plants. Most water-based sealers are already low in VOC’s, but to be sure, look for a sealer that contains under 50 grams of VOCs in each liter. High-VOC sealers contain 60 to 300g/L.

Better yet, if you can find a zero VOC sealer, then that’s the best choice.

Low and zero VOC sealers tend to have better durability requiring fewer reapplications, offer better protection especially on wood edges, are easier to apply, and much easier on the lungs after application.

Best Pressure Treated Wood Sealer

There are many high-quality sealers that do a terrific job on pressure-treated wood. Here are some examples that you can find on Amazon:

-   Seal Once Nano+Poly Ready Mix Penetrating Wood Sealer
-   #1 Deck Premium Semi-Transparent Wood Stain
-   Thompsons Waterseal Solid Waterproofing Stain

Other Considerations

While those are the best features to look for in a sealer for pressure-treated wood, here are some additional considerations:

Stain and Sealer for Pressure Treated Wood

Stains and sealers are two completely different products.

Wood stains affect its color, but will not protect the substrate. That’s why a stain won’t offer any protection against moisture and ultraviolet rays. However, a sealer protects without changing the color of the wood.

There’s no need to choose among the two if you want the benefits of both a stain and sealer. There are many two-in-one formulas out there that can improve the color of the wood while protecting it.

Type Of Wood

It’s also important to use a sealer that is compatible for the type of wood you have. Some products are designed for soft wood, while others are meant for use on hard wood. To be sure, read up on the manufacturer’s directions.

Generally speaking, clear sealers work best on all new decks since they enhance the beauty of the natural grains.

Drying Time

Different types of sealers have different drying times, and the range is wide.

They vary from an hour to as long as 12. Regardless, it’s critical that you apply the sealer when the temperatures are ranging from 60 to 90 F, with a maximum of 50% humidity. This helps ensure that the drying time is as quick and efficient as possible.


With these guidelines, you’re now ready to seek out the best sealer for your pressure treated wood projects.

Frequently Asked Questions

How often should pressure treated wood be sealed?

Pressure treated wood should be maintained with routine sealing as soon as construction of it has finished, followed by reapplication every year or so.

You can also conduct a simple test if the substrate is ready for resealing. Just pour a minute amount of water on the surface, and if it beads up, then that means it’s still properly sealed. On the other hand, if the wood absorbs the water, it’s time to reseal it.

Is it better to stain or seal pressure treated wood?

Sealing and staining pressure treated wood are two different processes.

The primary function of sealing is to protect the substrate, especially from moisture, mold and mildew, UV rays, and rotting. However, staining pressure treated wood can offer some form of protection against the same damages. Stains have a pigment or a tint and in some cases, it can help prevent UV rays from penetrating or rotting the wood.

Sealers do a better job at protecting the wood from moisture, while stains are usually more effective at preventing graying and rotting wood caused by exposure to the sun’s rays. Its efficacy at protecting from UV rays depends on the thickness of the color.

Stains reduce the visibility of wood grains, making it suitable for fir, pine, spruce, plywood, fences, OSB decks, or other similar surfaces. Meanwhile, sealing is recommended for certain types of wood such as mahogany, teak, or cedar since the process enhances its natural color and wood grain.

Depending on what you need, one may be better than the other but these days you can already opt to use a stain + sealer in one.

About the author

Hey, I'm Dale Keese.. thanks for reading.. hopefully this article can save you some time and trouble with your sealing job. I'm also in the process of making some video walk-throughs for youtube so check back soon! thanks

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