5 Best Treated Lumber Sealers


Looking for the Best Treated Lumber Sealer? We’ve done the legwork for you. Our guide cuts straight to the chase, highlighting the top wood sealers on the market that combine durability, aesthetic appeal, and ease of use. These products protect against UV rays and moisture, ensuring your outdoor wood stays looking great and lasts longer.

Applying wood stain to new wooden fence with a paintbrush.

Dive into our recommendations to find the ideal sealer for your deck, furniture, or fence and keep your outdoor wood in top condition season after season.

1. Seal-Once Marine Premium Wood Sealer

Seal-Once Marine Premium Wood Sealer

Seal-Once Marine steps up as the guardian of your wood structures, tailored specifically for harsh marine environments. Ideal for docks, swing sets, outdoor furniture, and decks frequently exposed to water, this premium sealer not only promises but delivers. Its water-based composition is a nod to eco-friendliness with no compromise on effectiveness—ultra-low in VOCs, non-toxic, and completely odorless.

Cleaning a wooden deck using a high-pressure water sprayer.

By penetrating deep into the wood, it creates a robust barrier that is both flexible and breathable, crucial for maintaining wood integrity. It skillfully prevents mold, mildew, and wood rot, stabilizes against warping, and lets the wood age naturally into a charming silver-gray. Safe for aquatic life and convenient for cleanup with just soap and water, Seal-Once Marine ensures your wood structures are protected, functional, and visually pleasing for up to a decade on vertical surfaces and six years on horizontal ones. It’s more than just a sealer—it’s a crucial investment for the long-term beauty and durability of your waterside retreat.

Jim, Florida: “Living near the coast, I always struggled with the salty air degrading my deck. Seal-Once has completely changed the game for me. It’s been two years, and my deck still looks fantastic!”

Sandra, Michigan: “I applied Seal-Once on my swing sets and outdoor furniture. Love that it’s eco-friendly and odorless. It’s held up beautifully through several harsh winters.”

Application Tips and Tricks

  • Preparation: Ensure the wood is clean and dry. Remove any previous coatings or debris. Allow new wood to weather for a minimum of six months to open up the grain for better penetration.
  • Ideal Conditions: Apply in dry conditions with temperatures above 50°F. Avoid direct sunlight during application to prevent rapid drying.
  • Maintenance: Clean the surface annually and check for areas that need touch-ups. Reapply every 2 to 3 years or as needed.

2. Ready Seal 515 5-Gallon Pail Pecan Exterior Wood Stain and Sealer

Ready Seal 515 5-Gallon Pail Pecan Exterior Wood Stain and Sealer

Ready Seal 515 is your straightforward, no-nonsense ally in the world of wood preservation, perfect for any exterior wood project needing a touch of pecan-colored charm. This oil-based stain not only beautifies with a semi-transparent finish that highlights wood grain and texture but also serves as a protective sealer. What sets it apart is its “Goof Proof” application system—there’s no need for primer, back brushing, or worry about uneven streaks or laps.

Wooden pergola with lattice design overlooking a backyard.

You can apply it with a sprayer, roller, or brush at any temperature, and it self-blends seamlessly on the wood surface. Initially dark, it settles into its true color within about two weeks, offering a long-lasting defense against mold, mildew, and harmful UV rays. The surface needs to be clean and dry, but once prepped, applying Ready Seal is a breeze, providing durability and beauty without the fuss. It’s particularly convenient in states with PaintCare recycling regulations, ensuring every step from application to disposal is handled with environmental responsibility.

Mark, Texas: “Absolutely love the no-fuss application of Ready Seal. The color matured beautifully on my cedar fence without any streaks or laps.”

Elaine, California: “The Goof Proof claim is real. I refreshed our backyard deck using Ready Seal, and it was forgiving even for a novice like me.”

Application Tips and Tricks

  • Preparation: Do not thin or dilute. Apply to dry wood free of dirt, mildew, and previous stains or sealers.
  • Ideal Conditions: Works in any temperature range, but avoid applying in direct sunlight or on extremely hot days to ensure even absorption and prevent lap marks.
  • Maintenance: Periodic reapplication every 2 to 3 years is recommended, depending on exposure to elements and foot traffic.

3. Thompson’s WaterSeal

Thompson’s WaterSeal

Thompson’s WaterSeal is a jewel in the crown for anyone looking to enhance and protect their outdoor wood surfaces. This transparent waterproofing stain not only enriches your wood with a smoothly tinted hue but also allows the texture to remain visible, providing a natural yet polished look. Engineered to exceed industry standards, it battles against water damage and shields your wood from the harsh realities of UV rays with its advanced polymer technology, ensuring the color remains fade-resistant throughout the year.

Staining a deck with a brush next to a sliding door.

Whether sprucing up a weather-worn deck or sealing a brand-new fence, this product simplifies the application process. It can be applied to both damp and dry wood, adapting flexibly to your project’s needs. For optimal results, start with a clean surface, free from dust, oil, and previous coatings. Once prepped, Thompson’s WaterSeal goes on smoothly, offering a robust barrier that not only preserves but enhances the wood’s natural charm. Ideal for a range of wood types, this stain stands out for its easy application and lasting beauty, making it a top choice for both DIY enthusiasts and professional builders alike.

Derek, Washington: “I used Thompson’s on my patio and was impressed with how well it allowed the wood’s texture to show through while protecting against rain.”

Amy, New York: “This stain was easy to apply even on damp wood, and it’s kept my garden furniture looking great. Plus, it’s really held its color well against the sun.”

Application Tips and Tricks

  • Preparation: Clean the wood thoroughly with a deck cleaner to remove mildew and residues. Allow the wood to dry completely.
  • Ideal Conditions: Apply on a clear day with temperatures between 50°F and 90°F. Ensure there’s no rain forecast for at least 24 hours.
  • Maintenance: Inspect annually and reapply as needed, especially in high-traffic areas or regions with severe weather conditions.

4. #1 Deck Premium Semi-Transparent Wood Stain

#1 Deck Premium Semi-Transparent Wood Stain

Step up your outdoor wood care with #1 Deck Premium Semi-Transparent Wood Stain, a top-tier choice for safeguarding and beautifying your decks, fences, and outdoor furniture. This dual-action formula serves as both a stain and sealer, providing a shield against damaging UV rays while enhancing the wood’s natural appeal. Choose from four stunning semi-transparent shades—Natural, Cedar, Light Walnut, and Dark Walnut—each designed to dry to a flat, natural-looking finish that lets the original wood texture shine through.

Finished wooden deck with railing in a backyard.

Not only does it protect your wood from the usual wear and tear and UV damage, but it also makes maintenance a breeze with its water-based composition, ensuring easy cleanups and low odor during application. Covering 100-150 square feet with just two wet-on-damp coats, this stain extends the life of softwoods like cedar and redwood, keeping them vibrant and strong through seasons of sun and rain. It’s the perfect blend of durability and aesthetic charm, making your wood installations not just visually appealing but structurally sound for years to come.

Carlos, Arizona: “I’ve tried various brands, but #1 Deck really makes my deck pop while protecting it. The UV protection is top-notch!”

Rebecca, Ohio: “The application was straightforward, and I’m thrilled with the natural finish. It’s protected my porch beautifully through seasons of snow and rain.”

Application Tips and Tricks

  • Preparation: Sand smooth surfaces for better absorption. Clean all surfaces thoroughly to remove old finishes and debris.
  • Ideal Conditions: Best applied in mild temperatures between 50°F and 80°F. Overcast days are ideal to prevent quick drying.
  • Maintenance: Clean the surface regularly and reapply every few years or when signs of wear and fading appear.

5. Rust-Oleum Varathane Spar Urethane

Rust-Oleum Varathane Spar Urethane

Rust-Oleum Varathane Spar Urethane is the shield your outdoor wood surfaces need against the elements. Whether it’s furniture, doors, windows, or fences, this water-based urethane enhances the natural beauty of the wood while providing formidable protection. With a crystal clear, satin finish that resists yellowing, your wood maintains its pristine appearance longer. Its standout feature is its superior weather and UV resistance, ensuring your outdoor installations remain unscathed by the sun’s harsh rays and inclement weather.

Garden bench being stained on a patio next to garden tools.

Application is a breeze—drying to the touch in just 30 minutes and covering up to 87 square feet per quart. You can apply three coats in a single day, making it exceptionally time-efficient. The non-yellowing formula not only preserves the wood’s natural charm but also adds to its durability, protecting it from scratches, stains, and moisture. Low odor and no visible brush strokes mean your projects stay clean and smooth, reflecting true craftsmanship. For those looking to maximize protection while minimizing effort, Rust-Oleum Varathane Spar Urethane offers an ideal solution—robust, reliable, and remarkably clear.

Neil, Florida: “The best for any wood that faces lots of sunlight and moisture. It dries fast and doesn’t yellow over time.”

Jenna, Minnesota: “I applied it to our outdoor window trims, and the finish is as clear and beautiful as day one. Plus, the low odor was a big plus for us.”

Application Tips and Tricks

  • Preparation: Sand the surface lightly if previously finished, and ensure it’s free of dust and oils. Apply a minimum of four coats for the best protection.
  • Ideal Conditions: Apply in temperatures between 55°F and 90°F, in low humidity to avoid trapping moisture under the finish.
  • Maintenance: Use mild cleaners for routine cleaning. Inspect annually and apply an additional coat every few years to maintain optimal protection.

Comparative Analysis of Top Treated Lumber Sealers

FeaturesSeal-Once MarineReady Seal 515Thompson’s WaterSeal#1 Deck PremiumRust-Oleum Varathane
DurabilityHighModerateHighHighVery High
Eco-FriendlinessVery HighModerateModerateHighHigh
Ease of ApplicationEasyVery EasyEasyEasyVery Easy
UV ProtectionExcellentGoodGoodExcellentExcellent
Water ResistanceExcellentGoodExcellentExcellentExcellent
Ideal forMarine WoodGeneral WoodOutdoor WoodSoftwood TypesOutdoor Wood Surfaces
VOC LevelsUltra-LowLowModerateLowLow
Aesthetic FinishTransparentSemi-TransparentTransparentSemi-TransparentClear
Safety (Pets/Plants)SafeSafeSafeSafeSafe


  • Seal-Once Marine is best for those near water bodies, offering superb eco-friendliness and excellent durability, ideal for harsh marine conditions.
  • Ready Seal 515 stands out for its cost-effectiveness and extremely easy application, making it a great choice for beginners and large projects.
  • Thompson’s WaterSeal offers solid water resistance and is ideal for those who prefer a natural wood appearance with a transparent finish.
  • #1 Deck Premium is perfect for softwoods, providing great UV protection and a balance of aesthetics and durability.
  • Rust-Oleum Varathane excels in areas with high exposure to sun and moisture, providing the best durability with a crystal clear finish that doesn’t yellow.


In conclusion, selecting the right wood sealer is essential for protecting and enhancing your outdoor wood projects. From docks to decks, furniture to fences, the right sealer not only extends the life of your wood but also improves its appearance, making it withstand the rigors of weather and wear. Each of the sealers reviewed offers unique benefits, whether it’s eco-friendliness, ease of application, or durability against UV rays and moisture. By considering the specific needs of your project and the qualities of these top picks, you can ensure that your outdoor wood remains vibrant and durable for years to come. Armed with the right information and products, you’re now ready to tackle any wood sealing project with confidence and achieve professional-grade results.


  1. How often should I reapply the wood sealer?
    The frequency of reapplication varies depending on the product, the climate, and the wood’s exposure to elements. Typically, reapplication is recommended every 1 to 3 years. Always check the manufacturer’s guidelines for the best results.
  2. Are these sealers safe for use around pets and plants?
    Most modern wood sealers, especially water-based ones, are non-toxic and safe for use around pets and plants. However, it’s important to allow the sealer to fully dry before allowing pets or people to come into contact with the treated surfaces. Always verify the safety information on the product label.
  3. Can I use these sealers on any type of wood?
    While most sealers are versatile enough to be used on a variety of wood types, certain products are better suited for specific woods like cedar, redwood, or pressure-treated pine. Check the product specifications to ensure compatibility with your particular wood type.
  4. What is the best way to apply wood sealer?
    Wood sealers can be applied using a brush, roller, or sprayer. For best results, follow the manufacturer’s application instructions. Ensure the wood is clean, dry, and free of old finishes for optimal adherence.
  5. Do I need to apply a primer before using a wood sealer?
    Most modern wood sealers are designed to adhere directly to the wood without the need for a primer. However, some specific products might require a primer to enhance the durability and effectiveness of the sealer, especially on highly porous woods.
  6. What should I do if the sealer starts peeling or flaking?
    Peeling or flaking usually occurs due to improper application or preparation. To fix this, remove the old sealer completely using a stripper or sander, clean the surface thoroughly, and reapply the sealer according to the manufacturer’s instructions.
  7. Are there any environmental considerations with using wood sealers?
    Eco-friendly wood sealers are available, which are formulated to have lower volatile organic compounds (VOCs) and are less harmful to the environment. Look for products with environmental certifications or those labeled as low-VOC.

We hope this guide has illuminated the path to finding the perfect wood sealer for your outdoor projects! Your deck, patio furniture, and fences deserve the best protection and care, and we’re confident that one of these top picks will suit your needs perfectly.

Do you have experiences with any of these products, or is there another sealer you swear by? We’d love to hear from you! Drop a comment below to share your thoughts and tips with fellow readers. If you found this article helpful, please consider sharing it with friends or on social media. Your feedback helps us improve and provide even more valuable information in the future. Happy sealing!

David Murray
David Murray
Forestry Author

I'm David Murry, a forestry equipment specialist with a focus on chainsaw operation. With over 13 years of experience, I've honed my skills in operating and maintaining a wide range of machinery, from chainsaws to log splitters. My passion for the outdoors and commitment to sustainable forestry drive my work, which emphasizes safety, efficiency, and staying updated with industry advancements. Additionally, I'm dedicated to sharing my expertise and promoting environmental awareness within the forestry community.


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