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Best Outdoor Wood Sealers of 2021

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Don’t let your exterior wood suffer. Get protected with these amazing wood sealers.

Who doesn’t love working with wood? We all do. It looks good, adds texture and color to your project, and it is tactile. However, wood has one significant problem; it rots if left untreated.

The best outdoor wood sealers protect your wood from the sun, rain, and extreme weather conditions to keep it looking good for years. We run down our top 10 products, rating them for performance, durability, and value for money.

Our Top Picks

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Model
Product Comparison Table
Features
Product Image of the DeckWise Ipe Oil Hardwood Deck Semi-Transparent 250 VOC Natural Finish (1-Gallon)
Best Oil-Based
DeckWise Ipe Oil Hardwood Deck Stain
  • Translucent finish enhances the wood grain
  • Applies in one coat
  • Low VOC for reduced odors
Product Image of the Ready Seal 512 5-Gallon Pail Natural Cedar Exterior Stain and Sealer for Wood
Best for Cedar
Ready Seal 512 5-Gallon Natural Cedar Exterior Sealer
  • Applies without a primer
  • No need to dilute
  • Goes on in one coat
Product Image of the Star brite Premium Golden Teak Oil - Sealer, Preserver, & Finish for Outdoor Teak & Other Fine Woods, 32 oz
Best for Oak
Star Brite Premium Teak Oil Sealer
  • Perfect for all fine woods
  • Contains UV absorbers
  • Lasts 6 times longer than other teak oils
Product Image of the Cabot 140.0003460.005 Australian Timber Oil Stain, Quart, Jarrah Brown
Best for Pine
Cabot Australian Timber Oil Stain
  • Ideal for softwood-like pine
  • Great coverage for smooth surfaces
  • Added UV safeguarding
Product Image of the SEAL-ONCE Marine Ready Mix - 1 Gallon Penetrating Wood Sealer Waterproofer & Stain (Natural). Water-Based, Ultra-Low VOC Formula for high-Moisture Areas to Protect Wood Docks, Decks & Piers.
Best Deck Sealer for Treated Wood
Seal-Once Marine 1-Gallon Penetrating Wood Sealer
  • Plant, animal, and marine life-friendly
  • Acts like an oil-based sealant
  • Ideal for boat decks and docks
Product Image of the Minwax 33250000 Helmsman Spar Urethane Aerosol, 11.5 ounce, Gloss
Best Deck Sealer for Treated Wood
Minwax 33250000 Helmsman Spar Urethane Aerosol
  • Aerosol application
  • Dries clear (perfect for light-colored woods)
  • Contains UV blockers
Product Image of the TotalBoat Lust Marine Varnish, High Gloss and Matte Finish for Wood, Boats, Outdoor Furniture (High Gloss, Quart)
Best Marine-Grade
TotalBoat Lust Marine Varnish
  • Apply multiple coats in one day
  • Guaranteed not to peel or crack
  • Expands and contracts with the weather conditions
Product Image of the Rust-Oleum 250141H Ultimate Spar Urethane Water Based, Quart, Semi Gloss Finish
Best for UV Protection
Rust-Oleum 250141H Ultimate Spar Urethane Deck Sealer
  • Superior UV protection prevents fading
  • Restricts mold and mildew growth
  • Touch-dry in 30 minutes
Product Image of the Eco Advance Wood Siloxane Waterproofer Concentrate - Makes 1 Gallon
Best Natural Sealer
Eco Advance Wood Siloxane Waterproofer
  • Safe for animals, children, and the environment
  • Low VOCs
  • 16-ounce concentrate makes up a gallon of sealer
Product Image of the THOMPSONS WATERSEAL TH.041821-16 Transparent Waterproofing Stain, Maple Brown
Best Clear Sealer
Thomsons Waterseal Transparent Waterproofing Stain
  • Dries transparent (enhances wood grain)
  • 5 different shades
  • Dries in just 2 hours

Why Should I Seal My Exterior Wood?

You should seal your external wood for one simple reason; it will rot if you don’t. The best exterior wood sealers are designed to form a protective layer over the wood, keeping UV light at bay and repelling rainwater.

You need to keep moisture from penetrating your wood because not only does it rot the material, but if it freezes in cold weather, which expands and splits the wood.

UV light is also a problem because it causes wood to dry and split. Faded wood looks tired and unsightly, but if you treat it, it retains its rich natural color.

Types of Wood Sealer

Essentially, there are two types of wood sealer: water-based and oil-based. But what are the differences, and is one better than the other?

Water-Based

Product Image of the Rust-Oleum 250141H Ultimate Spar Urethane Water Based, Quart, Semi Gloss Finish

Water-based sealers are excellent at repelling UV light, thanks to the protective layer they create on the surface of your wood. It stops harmful rays of light fading your wood to a pale gray.

Your wood will crack and crumble if left untreated as the sun dries it out. Water-based sealers are ideal because the sun never reaches the wood beneath the protective coating.

The downside with this type of sealer is it chips and flakes easier than oil-based varieties, and if that happens, water gets under the surface and starts to rot the wood.

Water sealants are easier to apply because you can brush, roller, and spray it on, plus the cleanup is a lot easier because all you need is detergent and water.

Oil-Based

Product Image of the DeckWise Ipe Oil Hardwood Deck Semi-Transparent 250 VOC Natural Finish (1-Gallon)

Oil-based sealants work slightly differently from water-based varieties. While you can apply them using similar methods, although if you want to spray it on, you may need to thin the sealant, the oil penetrates rather than creating a topcoat protective layer.

As the wood absorbs the oil, it protects from the inside out, stopping water from soaking into the material. Oil-based sealers are more robust, last longer because they don’t scuff and chip, and generally are easier to reapply when the wood needs seasonal treatment against the elements.

Cleanup is more challenging because you need a mineral spirit to wash away the oil residue. Also, oil is more toxic because it throws off volatile organic compounds (VOCs), which are irritating to the eyes and nasal passages if inhaled. Oil is also worse for the environment.

How To Choose the Best Outdoor Wood Sealers

Naturally, there are differences between each type of sealer and each product. So, what should you be looking for? Here’s a handy guide.

Ease of Application

How you apply the sealer is a significant factor when choosing a product to use. Oil-based options generally are brushed on rather than sprayed. Some do allow you to spray it on, but you might need to use a thinner to get the right consistency.

Water-based solutions are more forgiving when it comes to how you apply them. They are thinner, so they lend themselves to spraying, brushing, and rolling. You might also find that water-based sealers need 2 or even 3 coats to form a protective layer.

Oil-based sealants only need 1 or 2 coats to do the same job.

Environment Concerns

If you care about the environment, the type of sealer you use makes a difference. Water-based formulas have less impact on the environment. They wash away with soap and water and don’t have the same VOC problem that oil-based sealers do.

Oil-sealers have issues with odors and harmful VOCs. Some are low VOC, but you might still suffer from headaches, irritated eyes, and a sore throat if you breathe it in.

You also need to use mineral spirits or chemical thinners to clean up after you have finished sealing your woodwork.

UV Light

If you live in California or somewhere with high sunshine values, you should see UV rays as a threat. Wood dries and cracks under extended periods of sunshine. Water-based sealers are better at dealing with this because they form a protective layer on the surface of the wood.

Oil still has safeguarding qualities, but because the oil absorbs into the wood, it suffers more from UV light.

Drying Time

Most water-based sealers are touch dry within 1 to 3 hours if applied in perfect conditions of 90 degrees Fahrenheit and 50 percent humidity. You might need to wait 24 hours for the sealer to cure fully, especially if you are painting a garden deck.

Oil-based solutions take a little longer to dry. Typically, you will need between 4 and 12 hours before it is touch dry, but you should wait 48 to 72 hours for the sealer to cure.

How Many Coats?

The number of coats you apply depends on the type of sealer you are using. Oil-based sealers require fewer coats because they penetrate deeper into the wood, while water-based products need more layers to form that hardened protective shell.


The Best Outdoor Wood Sealers of 2021

Finding the best outdoor wood sealers is a challenge. We narrowed down the selection to bring you the 10 best wood sealers based on price, performance, and ease of use.

1. DeckWise Ipe Oil Hardwood Deck Stain

Best Oil-Based Outdoor Wood Sealer

This DeckWise oil-based sealer is not a budget option, but it does penetrate deeper into the wood. It’s perfect for all external wooden surfaces, including decks, railings, and fences.

You get UV protection because the formula contains trans oxide pigments. It protects against mold and mildew and has a 250 low VOC to keep odors to a minimum.

The other great thing about this sealer is it applies in just one coat, so you get instant protection, and you don’t need to worry about drying times between layers. It’s guaranteed not to crack, bubble or peel.

Because this sealer is translucent, it enhances the natural grain of the wood, and if you have exotic woods like bamboo, it does an excellent job of protection. The only downside is the trans oxide slightly yellows the color, and it is not available in California.

Pros

  • Translucent finish enhances the wood grain.
  • Applies in one coat for speed and convenience.
  • Low VOC for reduced odors.
  • Guaranteed not to crack, bubble or peel.

Cons

  • Trans oxide particles slightly discolor the stain.
  • Not a budget option due to the costs.

Additional Specs

Size 1 liter
Type Oil-based
Coverage 250 sq ft
Application Brush, roller, spray
Price $$$

2. Ready Seal 512 5-Gallon Natural Cedar Exterior Sealer

Best Outdoor Sealer for Cedar

Caring for cedar takes a specific outdoor sealer. This Ready Seal requires no primer, saving you preparation time, and it can be applied using a brush, sprayer, or roller.

There’s no need to back brush, and it is guaranteed never to leave lines, runs, or streaks. You can forget about the wet-line application because it will self-blend, and it applies in most temperatures within the acceptable range.

This sealer is runny enough that you don’t need to dilute it if you are using a sprayer, and because it only requires one coat, you save time, money, and extra effort.

The only thing to watch for is when you initially coat your deck; the color is very dark. It takes 14 days for the true color to appear, so there’s no need to panic. Between coats, you also need to wait 48 to 72 hours for the sealer to cure.

This cedar deck sealer comes in 5-gallon tubs. That’s enough to seal every piece of cedar in your home and garden and still have some left over for next year.

Pros

  • Applies directly to the wood without a primer.
  • No need to dilute the paint formula.
  • Goes on in one coat to save time and money.
  • Guaranteed not to run, steak, or leave lines.

Cons

  • Takes 48 to 72 hours to dry between coats.
  • 5 gallons might be too much for smaller jobs.

Additional Specs

Size 5 gallons
Type Oil
Coverage 900 sq ft plus
Application Brush, roller, sprayer
Price $$$

3. Star Brite Premium Teak Oil Sealer

Best Outdoor Sealer for Oak

Okay, so this is a teak sealer, but teak is hardwood, like oak, so the formula preserves all fine woods. It uses tung oil polymers to provide enhanced protection for your oakwood.

It contains UV absorbers to protect against fading, sun damage, and weathering, and it stops your oak from graying and splitting. After just one application, it starts working to protect and enhance your natural oakwood grain.

This sealer is easy to apply, fast-acting and lasts 6 times longer than other teak oils. It’s also effective on marine teak decks. However, you only get 100 square feet of coverage from a 32 fluid ounce bottle, which is pretty meager compared to some sealers.

Pros

  • Perfect sealer for all fine woods.
  • Contains UV absorbers for increased sun protection.
  • Lasts 6 times longer than other teak oils.
  • East to apply and fast-acting.

Cons

  • Limited coverage means small projects only.
  • Not suitable for softwoods.

Additional Specs

Size 32 fluid ounces
Type Oil
Coverage 100 sq ft
Application Brush or pad
Price $$

4. Cabot Australian Timber Oil Stain

Best Outdoor Wood Sealer for Pine

This translucent treatment is the perfect candidate for protecting softwood like pine. Softwoods are susceptible to rot if they aren’t protected properly, so this sealer penetrates deep into the wood to fully protect and seal.

You also get UV protection, thanks to iron oxide pigments in the formula, which is important if you live in an area with a lot of sunshine. It dries flat and translucent, and you get approximately 400 to 600 square feet of coverage on smooth surfaces and 250 to 350 square feet on rough surfaces.

The magic of this formula consists of 3 elements: linseed oil for penetration, long-oil alkyds for increased durability, and pure South American Tung oil for color.

The only downside is the small 1-quart tins, making larger projects expensive because you will need extra supplies.

Pros

  • Ideal for softwood-like pine.
  • Great coverage for smooth surfaces.
  • Iron oxide pigments for added UV safeguarding.
  • Formula contains linseed and tung oil.

Cons

  • Could be costly if you are covering a large area.

Additional Specs

Size 1-quart
Type Oil
Coverage 400 to 600 square feet
Application Brush, roller, pads
Price $$

5. Seal-Once Marine 1-Gallon Penetrating Wood Sealer

Best Deck Sealer for Treated Wood

Pressure-treated wood needs extra care. Shaped and molded decks on boats are susceptible to many threats that land-based timber doesn’t get. Saltwater and extreme sunlight can age and weather pressure treated wood quickly.

This Marine-grade sealant is ideal. It utilizes nanotechnology to deeply penetrate to a cellular level, and it performs like an oil-based sealant but without harmful chemicals and volatile organic compounds.

This product is child-safe and non-harmful to marine life, so coating your boat deck will not impact the environment. It has been specially formulated to perform in and around saltwater, so it’s ideal for staining and protecting wooden decks and docks.

You get 9 color choices, ranging from natural and coastal to black. This sealant is sold in 1-gallon tins, making it an expensive option when you compare the cost against the 5-gallon Ready Seal. The same quantity of this sealer would cost you double the price!

On the plus side, the company is so confident this product performs; they guarantee the vertical elements of your woodwork are protected for up to 10 years, and you also get up to 350 square feet of coverage.

Pros

  • Plant, animal, and marine life-friendly.
  • Acts like an oil-based sealant with deep penetration.
  • Ideal for boat decks and docks.
  • 10-year protection on all vertical surfaces.

Cons

  • At the current per-gallon price, this is an expensive option.

Additional Specs

Size 1-gallon
Type Water
Coverage 250 to 350 sq ft
Application Brush, roller, pad
Price $$$$

6. Minwax 33250000 Helmsman Spar Urethane Aerosol

Best Deck Sealer for Treated Wood

This Helmsman Spar Urethane aerosol contains UV blockers, so it prevents graying and fading. Because it’s a spray can, applying this sealer is about as easy as it gets. And the price of this can is a lot less than comparable sealers.

Once you spray on one coat, you get instant rain and moisture protection, and the specially formulated oils expand and contract with the weather conditions to reduce flaking and cracking.

It dries crystal clear and is ideal for light-colored woods. Once applied, it dries quickly and cleans up with warm soapy water.

Because this is such a small spray can, it is limited to smaller projects like exterior tabletops, furniture, and boat decks. Plus, aerosols are not the most accurate way of sealing your woodwork, so you might get overspray.

Pros

  • Aerosol application makes it idiot-proof.
  • Dries clear and is perfect for light-colored woods.
  • Contains UV blockers to safeguard against sunlight.
  • Dries quickly and cleans up with warm water.

Cons

  • Only comes in an 11.5-ounce can.
  • Overspray is likely due to inaccurate aerosol.

Additional Specs

Size 11.5 ounces
Type Oil
Coverage 100 sq ft per quart
Application Aerosol
Price $

7. TotalBoat Lust Marine Varnish

Best Marine-Grade Outdoor Wood Sealer

This marine-grade varnish is fast-drying, which means you can apply multiple coats in a single day. It’s dry and ready for recoating within an hour at 72 degrees Fahrenheit. The premium oil-based formula is guaranteed not to peel or crack and it expands and contracts with the weather conditions.

Once applied, you get a high-gloss finish that enhances the wood grain and protects against moisture, UV rays, and extreme weather events.

The coverage is pretty impressive, with up to 400 square feet, so you get a lot with one tin. However, to achieve such a high-gloss finish, the manufacturer recommends you paint on at least 6 to 8 coats.

Applying this varnish is easy. It can be rolled, painted, and sprayed, but you would need to thin the formula with xylene if you want to spray it.

This varnish comes in matte and gloss, but matte is not recommended as a base-coat sealer. You need the gloss for that.

Pros

  • Apply multiple coats in one day.
  • Guaranteed not to peel or crack.
  • Expands and contracts with the weather conditions.
  • Excellent 400 square feet of coverage.

Cons

  • Only gloss is suitable as a base-coat sealer.

Additional Specs

Size 1-quart
Type Oil
Coverage 400 square feet
Application Paint, roller, spray
Price $$$

8. Rust-Oleum 250141H Ultimate Spar Urethane Deck Sealer

Best Outdoor Wood Sealer for UV Protection

This water-based poly sealer has enhanced UV protection to stop your exterior wood from fading and cracking. And best of all it is a well-known US brand.

The first coat dries to the touch within 30 minutes, which means a second layer is possible within 2 hours. You get up to 87 square feet of coverage, so you don’t get the same quantities as other products, but it is ideal for smaller projects. The cleanup is easy with warm soapy water.

When the topcoat cures, it seals the wood, protecting it from UV rays. It won’t fade or yellow, and it restricts mold and mildew growth.

You get various finishes, from gloss, semi-gloss, and satin, and it applies with a brush, roller, or sprayer. However, much like the TotalBoat varnish, you need many layers to achieve a long-lasting seal against the elements.

Plus, for such a small tin, you will incur increased costs if you want to achieve the highest levels of protection.

Pros

  • Superior UV protection prevents fading.
  • Restricts mold and mildew growth.
  • Touch-dry in 30 minutes and recoats in 2 hours.
  • Easy cleanup with warm soapy water.

Cons

  • Limited coverage of 87 square feet.
  • Requires 4 layers to achieve total protection.

Additional Specs

Size 1-quart
Type Water
Coverage 87 square feet
Application Brush, roller, sprayer
Price $$

9. Eco Advance Wood Siloxane Waterproofer

Best Natural Outdoor Wood Sealer

When you want a sealer that is kind to the environment, try this Eco Advance. Unlike the other products to feature, this bottle is a concentrate that makes up to 1-gallon of sealant.

It’s ideal for wood decking, outdoor furniture, and fences. It protects against mold, mildew, salt stains, water damage, and pool chemicals. It’s breathable, dries clear, and sprays on. You can even use it directly on new wood.

What makes this sealant unique is it is safe for pets, children, plants, and wildlife. It has no impact on the environment, and as with all Eco products, it contains almost zero VOCs, so you won’t suffer from headaches and a sore throat when applying this sealant.

Pros

  • Safe for animals, children, and the environment.
  • Low VOCs make it safer to use.
  • 16-ounce concentrate makes up a gallon of sealer.
  • Breathable and applies to new wood.

Cons

  • You need to mix the solution yourself.

Additional Specs

Size 16-ounce concentrate
Type Water
Coverage 240 square feet
Application sprayer
Price $

10. Thomsons Waterseal Transparent Waterproofing Stain

Best Clear Outdoor Wood Sealer

Thomsons is another trusted and popular brand of sealant. This one is transparent, so it dries crystal clear to leave you marveling at the grain of your wood. It is UV and moisture-resistant, so your wood won’t rot, fade or crack, and you can apply it by brush, pad, or sprayer.

You get 3 years of protection for your deck with just one coat, and your fence is safeguarded for 4 years. You can even apply this to fresh or damp wood, and it still offers the same level of protection.

This sealant is also available in 5 different stains, from acorn brown to woodland cedar, and depending on the wood surface, you get between 150 and 400 square feet of coverage. This formula is dry in just 2 hours, so you should get multiple coats done in a day.

Pros

  • Dries transparent to enhance the wood grain.
  • Available in 5 different shades.
  • Dries in just 2 hours for multiple coats.
  • Covers up to 400 square feet depending on the surface quality.

Cons

  • Some customers complain it leaves streaks and lines.

Additional Specs

Size 1-gallon
Type Water
Coverage Maximum 400 square feet
Application Brush, pad, roller, sprayer
Price $$

Wood Sealer Comparison Chart

Product Best Size Type Coverage Application Price
DeckWise Ipe Oil Hardwood Deck Stain Best Oil-Based 1 liter Oil-based 250 sq ft Brush, roller, spray $$$
Ready Seal 512 5-Gallon Natural Cedar Exterior Sealer Best for Cedar 5 gallons Oil 900 sq ft plus Brush, roller, sprayer $$$
Star Brite Premium Teak Oil Sealer Best for Oak 32 fluid ounces Oil 100 sq ft Brush or pad $$
Cabot Australian Timber Oil Stain Best for Pine 1-quart Oil 400 – 600 sq ft Brush, roller, pads $$
Seal-Once Marine 1-Gallon Penetrating Wood Sealer Best for Treated Wood 1-gallon Water 250 – 350 sq ft Brush, roller, pad $$$$
Minwax 33250000 Helmsman Spar Urethane Aerosol Best for Treated Wood 11.5 ounces Oil 100 sq ft per quart Aerosol $
TotalBoat Lust Marine Varnish Best Marine-Grade 1-quart Oil 400 sq ft Paint, roller, spray $$$
Rust-Oleum 250141H Ultimate Spar Urethane Deck Sealer Best for UV Protection 1-quart Water 87 sq ft Brush, roller, sprayer $$
Eco Advance Wood Siloxane Waterproofer Best Natural 16-ounce concentrate Water 240 sq ft Sprayer $
Thomsons Waterseal Transparent Waterproofing Stain Best Clear 1-gallon Water Maximum 400 sq ft Brush, pad, roller, sprayer $$

FAQs

How Often Should I Seal My Deck?

You should seal your deck at least once every 1 to 2 years. A lot depends on the area where you live. If you get a lot of UV light, keeping that level of protection is crucial to stop the wood from fading, yellowing, and drying out.

Similarly, water penetration rots the wood, so if the sealer chips or peels, you will get moisture damage that could lead to mold and mildew issues later down the line.

How Should I Apply Deck Sealer?

Deck sealer can be applied using a brush or paint pad, a roller, although this is a less common method or a sprayer. You do have to thin the sealer using water or a mineral spirit, depending on the type of sealer, which means the layers will be thinner.

Can You Apply Wood Sealer to Wet Wood?

No, the wood should be dry and free from contaminants like old stains and wax coverings. Wet wood causes the sealer to bubble, which means it has not adhered properly, causing it to flake and peel.


Headshot of Mark Weir

About the Author

Mark Weir

Mark spent 24 years working in real estate, so he knows his way around a home. He also worked with contractors and experts, advising them on issues of planning, investments, and renovations. Mark is no stranger to hands-on experience, having renovated his own home and many properties for resale. He likes nothing better than seeing a project through to completion.

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