Homeowners have always struggled to keep outdoor wooden structures looking like they did on the showroom floor. UV rays, water, and mildew will eventually cause wood to rot. Fortunately, there’s a tried-and-true way to extend the life of this natural material. Wood sealer is a protective coating that is easy to apply and provides long-lasting protection.
Top 5 Outdoor Wood Sealers
| Image | Product | |
|---|---|---|
Editor's Choice | Thompsons WaterSeal Advanced
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Best Bargain Option  | Rain Guard Premium Water Sealer
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Best Clear Wood Sealer  | Thompsons WaterSeal Waterproofing Wood Protector
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Best for Composite Decks  | Defy Crystal Clear Composite Deck Waterproofing
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Best End Sealer  | Anchorseal 2 Logs and Lumber Sealer
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1. Thompsons WaterSeal Advanced – Editor’s Choice
Thompson’s WaterSeal Advanced is a maximum strength waterproofer and natural wood protector. The coating resists mildew growth, UV damage, and fading. It’s perfect for natural wood decks, fences, and furniture. You’ll notice significant improvements after just one coat.
Trusted for Years
Thompson’s Water Seal has earned customers’ trust by delivering quality products since 1920. They are continuously vetted by professionals. The large light-blocking jug can be resealed over and over again. Keep a bottle of WaterSeal Advanced on hand. You’ll always be prepared to preserve your outdoor wood projects.
Versatile
WaterSeal Advanced is one of the few sealers that can be applied directly to wet wood. With WaterSeal, there is no reason to dance around the weather. Most homeowners say they were able to apply this sealer in one day. The water-based formula can be applied with a paint pad, brush, sprayer, or roller. There’s no need for you to stir the product before applying it to your project.
It dries in two hours. Each gallon offers 150 to 400 square feet of coverage.
A single coat protects wooden decks for three years and wooden fences and siding for four years.
This maximum strength waterproofer produces long-lasting beading. Not to mention, it helps stop mold growth and damage from UV rays.
This semi-transparent formula is available in four different wood stain colors. You can use Thompson’s color guide to find the stain that is right for your exterior wood project.
A Few Issues
This water-based sealant contains minimal chemicals. It’s safe to use around children, pets, and plants.
Unfortunately, this product will peel and flake if it is applied over a loose stain. Users should take care to thoroughly clean their work surface before applying WaterSeal Advanced.
PROS
- Resistant to UV rays and 100% waterproof
- Maximum strength offered with a single coat
- Can be applied directly to damp or dry wood
- Easy to clean with soap and water
- Available in a variety of wood stains
CONS
- Treatment is slick when wet
2. Rain Guard Premium Water Sealer – Best Bargain Option
Rain Guard Premium Water Sealer is fortified by Micro-Lok, proprietary additives that allow the wood to absorb this solvent-based sealant. It creates a powerful hydrophobic barrier. Once treated, wood can not be affected by anything. According to the manufacturer, this barrier is impervious to rain, UV light, freezing temperatures, salt, dirt, and more.
This sealer can be used on virtually all porous wood surfaces. It is completely clear. As such, it will not alter nor enhance the appearance of wood. The formula is safe to use around people, pets, and plants. What’s more, it’s ready to use right out of the package.
Effective
A single gallon of Rain Guard Water Sealer can cover as much as 200 square feet of wood. Keep in mind that you need to apply at least two flood coats to achieve maximum protection. Temperatures must be somewhere between 40 and 80 degrees Fahrenheit at the time of application. The manufacturer recommends that you apply Rain Guard Watersealer using a low-pressure airless sprayer, such as those used for lawn and garden products.
This impressive product repels water.
It protects exterior wood from rot and decay. What’s more, it stops the spread of mildew, mold, and more. This product works well on wood, but it can also be applied to a variety of other surfaces, including driveways, exterior walls, and walkways.
Fights Against Sunlight
This formula contains UV-blocking stabilizers. The sealer will not yellow from exposure to sunlight. A single application is good for at least five years. Rain Guard’s five-year guarantee backs up this claim.
The powerful Rain Guard formula manages to do all this while remaining 100% eco-friendly. This water-based, low-VOC, low-odor formula is safe to apply. The main ingredients include a silane siloxane blend, Micro-Lok, and water.
A Few Limitations
Don’t expect to use this sealer on painted wood. According to the manufacturer, painted surfaces are a no-go for Rain Guard products. Since it’s only available in clear, colored tints are off-limits too. Since it is completely colorless and texture-free, you wouldn’t even know it’s there. Some consumers add colorants to the mixture to darken or tint it.
PROS
- Guaranteed coverage for up to five years
- 200 square feet of coverage per gallon
- Contains advanced UV stabilizers
- Long-lasting, non-yellowing formula
- Safe for people, pets, and plants
CONS
- Only available in clear
3. Thompsons WaterSeal Waterproofing Wood Protector – Best Clear Wood Sealer
Thompson’s WaterSeal Waterproofing Wood Protector is a super-durable clear wood sealer. It prevents water damage while maintaining the natural color of the wood.
It’s our top choice for decks, fences, and outdoor furniture that has a natural wood finish.
A Trusted Company
As previously mentioned, Thomson’s products are some of the most trusted in the industry. This century-old company is dedicated to developing excellent wood sealers and household improvement products. On top of that, all of their sealants are made and packaged in the United States.
A Crystal Clear Coating
We were impressed with the way water beaded on our deck after a single application of clear WaterSeal. However, some customers found that WaterSeal coatings did not fair as well as advertised when exposed to UV light. We also found that the application conditions were a bit over the top. When you add in prep and cleaning, it takes several days to properly apply a coat of WaterSeal. That said, the hard work is well worth it in the end.
PROS
- Clear coat that resists mildew and UV damage
- Comes in a durable metal can with handle
- Satisfaction guaranteed
- Protects surfaces while maintaining wood’s color
CONS
- Cannot be applied to damp wood
- Does not help with humidity issues
4. Defy Crystal Clear Composite Deck Waterproofing – Best for Composite Decks
We know what you’re thinking. You do not need to seal new composite decks. However, you should seal aging composite wood materials. This extremely durable waterproofing sealer prevents the unsightly black stains that develop on composite decking that is exposed to water.
Nano-Particle Technology
Defy Crystal Clear Composite Deck Waterproofing is fortified with UV-blocking zinc particles. These proprietary additives prevent color fade and fungal growth. A single application can extend the life of your composite deck by decades.
A Versatile Product
The crystal-clear finish won’t alter the look of your wood. While it is designed for use with composite decking, it can also be used on natural materials. Each 1-gallon container offers up to 200 feet of coverage. The product is inexpensive and easy to apply. Be sure to clean your deck before sealing.
PROS
- Water-based clear composite deck sealer
- Fortified with zinc nano-particle technology
- Extremely durable resins
- Easy to maintain, just apply a new coat on top of existing treatments
CONS
- For composite decks only
5. Anchorseal 2 Logs and Lumber Sealer – Best End Sealer
Our last pick is designed to preserve the ends of lumber and logs. It is proven to prevent 90% of end checking and splitting. The product is made from equal-parts water-based wax and plant-based polymers. As such, you’d be hard-pressed to find a greener product. What’s more, it’s proven to extend the life of exotic hardwood decking.
Prevents Drying Splits
Exotic hardwood decks are a huge investment. This is why we always recommend that homeowners take the time to seal the ends of their decking. End protection is too often overlooked. A single application of Anchorseal adds years of life to decks and other outdoor wood products. It also preserves the look and structural integrity of exterior structures.
Hazard-Free Applications
The water-based formula does not contain chemical solvents. It’s safe to use around people and animals. You can clean it with a basic mixture of soap and water. You can apply the formula with virtually any painting tool, including a brush, roller, or sprayer. However, a high-powered sprayer produces the best result. A gallon of the formula offers roughly 100 square feet of coverage. However, coverage fluctuates depending on the application method and wood species.
PROS
- Anchorseal is for sealing the ends of logs and lumber
- Water-based wax and plant-based polymer formula
- Prevents 90% of drying splits
- Can be applied using a variety of methods
CONS
- Container is very flimsy
How to Choose the Best Outdoor Wood Sealer. Some Real-Life Tips
Now that you are familiar with some of the top exterior wood sealers, you’re probably wondering how to choose one for your project. Keep in mind that some products are designed to work on specific kinds of wood.
Waterproofing
Your exterior wood sealer must offer some sort of protection against water. Even chemically treated posts and composite decking are susceptible to water damage. Wood will rot and warp after excessive exposure to moisture. A waterproof coating will preserve the appearance and integrity of exterior wood surfaces. A quality waterproofer will cause beading.
Other Protections
Many exterior wood sealers contain UV-blocking additives, such as zinc particulates. Exposed wood surfaces will become faded and discolored after prolonged exposure to ultraviolet light. Sunlight can also cause exterior wood surfaces to split and warp.
Some products also prevent dark stains caused by mildew, fungi, and dirt.
Formula Basics
Many homeowners prefer to work with clear water-based sealers. These products do not alter the appearance of wood. They also tend to contain less chemical solvents. As a result, they are environmentally friendly and safe for use around kids and pets.
On the other hand, polyurethane sealants are made up of resins and sealants. They are not as eco-friendly as water-based products. However, they are undeniably durable. Not to mention, you can easily clean them with a mixture of soap and water.
Aesthetics
Most wood sealers fall into one of three categories: clear, semi-transparent, and tinted. You can choose a sealer than preserves the natural look of wood or one that brightens the wood’s appearance. Some sealants add color while still showing off some of the wood’s natural grain. It’s important to choose a sealer that will not yellow or develop blush.
Furthermore, look for a sealant that will not flake or peel over time.
Solid stains tend to offer more coverage than clear and semi-transparent sealers. Of course, the latter finishes do an excellent job of showing off wood’s natural texture and grain.
Ease of Use
Always allow the wood to dry before applying sealer. Waterproof barriers work both ways. Moisture trapped under a coat of sealant is especially detrimental. Wood should also be cleaned before it is sealed. In some cases, you will need to strip the surface of the preexisting finish.
Coverage
Check the expected coverage rate of your exterior wood sealer. Use that ratio (typically the number of square feet per gallon) to determine how many bottles of product you need to complete your project. Keep in mind that most exterior wood sealers dry quickly, leaving behind a durable film. You may need to rent a power sprayer if you have a lot of areas to cover. You might also want to consider the total cost of the product when tackling a large exterior project.
Keep in mind that coverage rates are often impacted by the porosity and condition of the wood. Older, softer woods require more product. Whereas, the product spreads more evenly on new hardwood.
FAQs
When should I use sealer?
All exterior wood should be sealed. Some people even choose to apply sealant under alternative finishes. Exterior wood structures are especially sustainable to UV and water damage. You can extend the life and look of your decks, fences, and other exterior wood projects with a sealant.
Can you apply wood sealer to wet wood?
Some sealants can be applied to wet wood. However, it is always preferable to apply a sealant to clean, dry surfaces. Read instructions thoroughly to ensure you prep and apply your sealant in the best possible manner.
How often do decks need to be sealed?
In most cases, decks need to be resealed every three years. You can perform a simple splash test to see if water beads up on the surface of the wood. If the water penetrates the wood, it’s time to apply a new coat of sealer. Many homeowners overlook the need to seal chemically treated and composite woods. If your exterior deck or fence is fading, warping, or rotting, then it is already succumbing to the elements.
How should I apply deck sealer?
The answer to this question depends on what product you are using. In general, exterior wood sealants can be applied with a variety of painting tools, including brushes, rollers, pads, and sprayers. Most wood sealers dry rapidly. It is important to use an application method that you can perform quickly.
Why should I seal my exterior wood?
Natural wood is attractive, but it’s difficult to maintain the look of wood that is exposed to the elements. Sealants protect against aesthetic and integral issues. Sealed wood is far less likely to crack, warp, rot, or split. It’s also less likely to change color or fade. A single bottle of wood sealant could help you avoid pouring thousands of dollars into future repairs.
Final Thoughts
We hope our guide helped you to find the exterior wood sealer that’s right for you. Our favorite happens to be Thompson’s WaterSeal Advanced. This impressive water-based sealer is super versatile and easy to apply. Not to mention, it doubles as a wood stain. However, there are lots of other amazing exterior wood sealers. Hopefully, our guide helped you to hone in on a product that is perfect for your exterior wood project.
Did you use an exterior wood sealer recently? Let us know how it went.
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