When it comes to keeping your deck looking great and standing strong year after year, choosing the right deck sealer is a game changer. Your deck faces all kinds of weather—from harsh sun and heavy rain to freezing winters and humidity. Without proper protection, wood can crack, warp, fade, or even start to rot. That’s why using a high-quality deck sealer is so important: it acts like a shield, locking out moisture, blocking harmful UV rays, and preventing mildew and mold.
But with so many deck sealers on the market, how do you know which one really works? Some claim to offer all-day waterproofing, others promise lasting UV protection, and some boast eco-friendly formulas. Sorting through all these claims can feel overwhelming, especially when you just want to get your deck sealed without hassle.
That’s why we put the 7 best deck sealers to the test. We carefully examined how well each product protects wood against water damage and sun exposure, how easy it is to apply, how long it lasts, and how it affects the look and feel of your deck. Our goal was to find sealers that provide real, long-lasting protection without complicated application or breaking the bank.
Whether you have a classic wood deck, pressure-treated lumber, or composite materials, there’s a sealer on this list that fits your needs. From the heavy-duty, marine-grade Seal-Once Marine Premium Wood Sealer that offers deep waterproofing and mildew resistance, to Rust-Oleum Varathane Spar Urethane, a great value option with solid UV protection, we’ve covered all the bases. We also highlight favorites for pressure-treated wood, the best waterproofing sealers, and easy-to-use concentrates perfect for beginners.
In this guide, you’ll find detailed reviews breaking down the pros, cons, and specs of each sealer. We’ll also walk you through what to consider before buying, how to apply sealers correctly, and answer common questions about deck maintenance. By the end, you’ll have all the info you need to choose the right deck sealer with confidence—so your outdoor space stays beautiful and protected for seasons to come.
Ready to see which deck sealer topped our list? Let’s dive in!
| Category | Product |
|---|
| Best Overall | Seal-Once Marine Premium Wood Sealer |
| Best Bang for the Buck | Rust-Oleum Varathane Spar Urethane Deck Sealer |
| Pressure-Treated Wood Pick | Thompson’s WaterSeal Transparent Wood Sealer |
Best Overall- Seal-Once Marine Premium Wood Sealer
If you want the best all-around protection for your deck, Seal-Once Marine Premium Wood Sealer stands out. Designed originally for marine environments, this sealer offers incredible waterproofing and mildew resistance while still allowing the wood to breathe.
What We Like
- Outstanding water and mildew resistance
- Breathable formula prevents peeling and cracking
- Non-toxic and eco-friendly
- Penetrates deep into wood for long-lasting protection
What We Don’t Like
- Higher price point than others
- Longer drying time (up to 24 hours)
Product Specs
- Coverage: 150-200 sq. ft. per gallon
- Dry time: 24 hours
- VOC: Low
- Application: Brush, roller, or sprayer
Best Bang for the Buck- Rust-Oleum Varathane Spar Urethane Deck Sealer
Rust-Oleum’s Varathane is a fantastic budget-friendly choice that doesn’t compromise on quality. It offers solid UV protection and a durable finish, perfect for decks exposed to strong sunlight.
What We Like
- Affordable price
- Excellent UV resistance to prevent fading
- Easy application and quick drying
- Clear finish that enhances wood grain
What We Don’t Like
- Less water resistance compared to premium options
- Can be a bit glossy for some tastes
Product Specs
- Coverage: 200 sq. ft. per gallon
- Dry time: 4-6 hours
- VOC: Medium
- Application: Brush or sprayer
Pressure-Treated Wood Pick- Thompson’s WaterSeal Transparent Wood Sealer
Thompson’s WaterSeal is a classic choice for pressure-treated wood decks. It offers reliable waterproofing and is widely available in stores.
What We Like
- Great waterproofing performance
- Dries clear with a natural wood look
- Easy to find at most retailers
- Fast drying time
What We Don’t Like
- Limited UV protection
- May need more frequent reapplications
Product Specs
- Coverage: 250 sq. ft. per gallon
- Dry time: 2-4 hours
- VOC: Medium
- Application: Brush, roller, or sprayer
Best for Waterproofing- Thompson’s WaterSeal Clear Wood Sealer
For those who want maximum water protection, this clear sealer from Thompson’s shines. It forms a strong barrier that keeps rain and snow out, perfect for wet climates.
What We Like
- Excellent water repellency
- Maintains natural wood appearance
- Fast drying and easy to apply
What We Don’t Like
- Minimal UV protection
- Requires frequent touch-ups in sunny areas
Product Specs
- Coverage: 250 sq. ft. per gallon
- Dry time: 2-4 hours
- VOC: Medium
- Application: Brush, roller, sprayer
Best with UV Protection- Defy Composite Deck Sealer
Defy stands out for protecting decks from sun damage with its advanced UV blockers. It’s a great pick if you live in a sunny region or have a deck exposed to direct sunlight most of the day.
What We Like
- Superior UV protection
- Water-based, low odor, and eco-friendly
- Enhances natural wood colors
- Mildew resistant
What We Don’t Like
- Slightly higher price
- Needs two coats for best protection
Product Specs
- Coverage: 200 sq. ft. per gallon
- Dry time: 6-8 hours
- VOC: Low
- Application: Brush or roller
Best Longevity- Olympic Maximum Oil-Based Clear Waterproofing Sealant
If you want a sealer that lasts a long time without peeling or cracking, Olympic Maximum’s oil-based formula is a winner. It penetrates deeply and forms a durable protective layer.
What We Like
- Long-lasting protection (up to 3 years)
- Deep penetration for wood preservation
- Water and mildew resistant
What We Don’t Like
- Strong odor during application
- Longer drying time (24+ hours)
- Oil-based, so cleanup requires solvents
Product Specs
- Coverage: 150-200 sq. ft. per gallon
- Dry time: 24 hours
- VOC: High
- Application: Brush or sprayer
Easiest to Use- Eco Advance Exterior Wood Water Repellent Concentrate
For first-timers or those who want a quick, simple option, Eco Advance’s concentrate is a breeze. It’s diluted with water, making cleanup easy and safe.
What We Like
- Easy to dilute and apply
- Low odor and eco-friendly
- Good water repellency for the price
- Concentrate lasts a long time
What We Don’t Like
- Less durable than premium sealers
- Needs reapplication every year or so
Product Specs
- Coverage: Variable depending on dilution
- Dry time: 4-6 hours
- VOC: Low
- Application: Brush, roller, sprayer
Before Buying Deck Sealer
Choosing the right deck sealer isn’t just about picking the most popular or cheapest option. Consider your deck’s wood type, local climate, and how much time you want to spend maintaining it. Some sealers excel in waterproofing, others in UV protection, and some offer both. Understanding these factors can save you money and effort down the road.
How We Tested the Best Deck Sealers
We applied each sealer to similar wood samples, then subjected them to real-world conditions: exposure to sunlight, rain, and temperature swings. We assessed how well they resisted water, fading, mildew, and cracking. Ease of application and drying time were also important factors in our scoring.
What to Consider When Choosing a Deck Sealer
While woods like cedar and redwood naturally resist water damage and insects, the most common material used for building new decks is pressure-treated wood. This type of wood is infused with chemicals to help protect it from moisture, but even pressure-treated wood isn’t completely immune to weathering. Without the right sealer, it can start to warp, crack, or splinter within just a few years.
It’s also important to note that not all sealers work on composite decking—a material made from wood fibers and adhesives pressed together. Before applying any sealer to a composite deck, make sure the product is compatible with that surface.
A good-quality deck sealer forms a protective barrier that keeps water out and helps extend the life of your deck. When choosing a sealer, think about the specific needs of your deck and the type of protection it requires to stay in great shape.
Oil-Based vs. Water-Based
Oil-based sealers tend to penetrate deeper and last longer but have stronger odors and longer drying times. Water-based sealers are easier to clean, low odor, and environmentally friendly but might require more frequent applications.
VOCs
Volatile organic compounds (VOCs) are chemicals released into the air by some sealers. Low VOC options are better for your health and the environment.
Water and Mildew Resistance
A good sealer should protect against water damage and prevent mold and mildew growth, especially in damp climates.
UV Protection
Sunlight can cause wood to fade and weaken. Sealers with UV blockers keep your deck looking vibrant longer.
Coats
Some sealers need multiple coats to work effectively. Check manufacturer recommendations and factor in your patience and time.
Drying Time
Quick-drying sealers let you finish your project faster, but slower drying sealers often provide more durable protection.
Tips for Using Deck Sealer
- Clean your deck thoroughly before sealing. Dirt and old finish can prevent proper adhesion.
- Apply sealers on a dry day with no rain in the forecast.
- Use a brush or sprayer for even coverage.
- Follow the recommended number of coats.
- Allow sufficient drying time between coats.
FAQs
How often should I reseal my deck?
Most decks need resealing every 1-3 years, depending on the sealer and climate.
Can I apply deck sealer over old stain or paint?
It’s best to remove old finishes before applying a sealer to ensure proper adhesion.
Is it better to use a clear or tinted sealer?
Clear sealers preserve natural wood color, while tinted sealers add color and additional UV protection.
Can I use a deck sealer on composite decks?
Some sealers are formulated specifically for composite materials; check the product label.
