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Wood is susceptible to mold, mildew, and rot if it is left exposed to rain, sleek, snow, and other moisture. Additionally, ultraviolet (UV) radiation can dry out wood, causing it to splinter and crack. So to protect your outdoor furniture, fence, or deck from ongoing damage, it’s necessary to apply paint, stain, or sealant to the wood. However, outdoor wood sealers are made specifically to bond to wooden objects in order to create a waterproof barrier and prevent wood rot.
We examined over 40 wood sealers that offer a wide range of color options, transparency, and finishes. We considered the durability and the resistance of each wood sealer, given that they are intended for use outdoors. Also, we looked at the type of wood sealer as well as the impact each product would have on the environment, preferring low-VOC or zero-VOC products over high-VOC wood sealers in our top 10 recommendations. I have even personally used a couple of the brands—Ready Seal and Olympic Stain—in fence repair and deck-building projects at home, and I’m pleased to report live up to expectations.
Depending on the type of outdoor wood sealer you invest in, it may also have UV stabilizers that block UV radiation from damaging the wood. Opaque wood sealers provide more UV protection than clear sealers, but the natural look of the wood is completely covered. Before you can make an informed decision while searching for the best outdoor wood sealer to protect your exterior structures, furniture, and other wooden objects, keep reading. There is more to find out about selecting an outdoor wood sealer below.
- BEST OVERALL: Seal-Once Nano+Poly Penetrating Wood Sealer
- BEST BANG FOR THE BUCK: Rain Guard Water Sealer
- BEST OIL-BASED: Ready Seal Exterior Stain and Sealer
- BEST WATER-BASED: Thompson’s WaterSeal Advanced Natural Wood Protector
- BEST SOLID: SaverSystems #1 Deck Wood Deck Paint and Sealer
- BEST SEMITRANSPARENT: SaverSystems #1 Deck Premium Semi-Transparent Stain
- BEST CLEAR: Wolman Raincoat Clear Oil Base Sealer
- BEST ECO-FRIENDLY: Eco Advance Wood Siloxane Waterproofer
- BEST UV PROTECTION: Seal-Once Marine Premium Wood Sealer
- ALSO CONSIDER: Olympic Stain Smartguard Multi-Surface Sealant
Types of Outdoor Wood Sealers
There are several types of wood sealers that are differentiated by the formula and transparency. The main types include oil-based, water-based, solid/opaque, semitransparent, and clear.
Oil-Based vs. Water-Based
Outdoor wood sealers can be split into oil-based and water-based products, each with its own drawbacks and benefits.
- Oil-based sealers are better for pine, cedar, oak, ash, and other types of wood that have a high absorption rate because oil-based sealers are not as easy for the wood to absorb as water-based products. However, an oil-based wood sealer typically has better UV resistance and tends to have a more even finish.
- Water-based sealers are ideal for wood with a low absorption rate, like alder, birch, and maple. They can also be used on oak and ash if a fast-drying alternative to oil-based sealers is needed. Water-based products are also more environmentally friendly, though the fast drying time can result in an uneven or splotchy appearance.
Solid or Opaque
The transparency of an outdoor wood sealer contributes to its ability to provide UV protection to the wood. Solid or opaque outdoor wood sealer is similar to paint because it completely covers the natural grain of the wood. This gives the wood a more uniform appearance in the color of the user’s choice.
Solid wood sealer is the best transparency option for UV protection because the thick layer or colored/tinted sealer helps to repel UV rays.
Semitransparent
The next option for sealant transparency are the semitransparent products. These sealers protect the wood from rain, moisture, rot, and mildew as well as providing mild UV protection with a semitransparent tint or color.
The semitransparent appearance allows the natural wood grain to show through. However, the color or tint in these sealants tends to fade faster than the color in solid or opaque sealers, so it may need to be reapplied about once every 2 to 3 years to maintain the appearance.
Clear
Paint and stains are commonly available in a wide range of colors, but most outdoor wood sealers have a clear finish because sealers are specifically intended to protect the wood from water, mold, and mildew.
UV protection is typically an added feature in clear sealers that results in a superior product, which allows such products to stand out from the competition. Clear sealers protect the wood without covering up the natural grain or natural color, though they are not as effective at repelling UV radiation as solid or semitransparent sealers.
What to Consider When Choosing the Best Outdoor Wood Sealer
Before coming to a conclusion about which wood sealant is the best protection for outdoor wood furniture, it’s necessary to understand some of the most important characteristics and product factors to look out for when deciding on the best outdoor wood sealer for a deck or fence.
Water and Mildew Resistance
The purpose of an outdoor wood sealer is to protect the wood from rain, sleet, snow, humidity, and any other type of moisture that can cause wood rot, mold, or mildew. By providing a waterproof layer with mold and mildew resistance, the wood sealer prevents the moisture from seeping into the fibers of the wood, causing swelling, shifting, warping, and tearing.
Mold and mildew pull moisture in from the air and collect rainwater to grow and thrive. This spreading growth can increase wood rot and also permanently discolor the wood, so it’s important to get rid of mold and mildew before it can start to spread.
Just keep in mind that the sealer repels all liquids, so it isn’t recommended to apply an additional layer of sealer after the initial layer has fully set because the sealer will not bond to the wood, it will just sit on top of a sealed horizontal surface or run down a sealed vertical surface.
UV Protection
Similar to water and mildew resistance, UV protection is intended to extend the life of the wood by preventing ongoing damage. Outdoor wood sealers are typically made for repelling water, but solid, semitransparent, and some clear sealers do have UV-resistant properties. Opaque or solid oil-based outdoor wood sealers with stabilizers offer the highest level of UV protection of any outdoor sealer.
Generally, oil-based sealers have a higher resistance to UV radiation than water-based sealers, while opaque/solid colors and tints shield the wood better than semitransparent or clear sealers. Semitransparent sealers still provide more UV protection than clear sealers, but if cracked and splintered wood from UV radiation is a recurring problem, it’s a good idea to invest in a solid oil-based wood sealer.
Application
Application of a sealer is important to consider. Most products can be applied with a paint brush or roller, and there are even some options that can be loaded into a paint sprayer. Oil-based sealers take longer to dry than water-based sealers, so make sure there is enough time for the sealer to cure before it rains.
Water-based sealers dry quickly, but if applying the sealer when it’s too hot outside, the sealer may dry in splotchy or uneven patches. For best results, start applying in the morning when it’s still relatively cool.
The number of coats and drying time of an outdoor wood sealer depend on the individual product. Even sealers made by the same manufacturer can have slight differences in coverage and drying time, though it should be noted that oil-based outdoor wood sealers typically need fewer coats than water-based sealers.
Environmental Concerns
A key factor to keep in mind when selecting an outdoor wood sealer for the deck, fence, or exterior furniture is whether the formula contains VOCs (volatile organic compounds) or any other ingredients that could be harmful to the environment. Oil-based sealers tend to have a higher percentage of VOCs, though many water-based sealers still have a low amount of VOCs in their formulas.
Check the product information and the details from the manufacturer to find out the level of VOCs contained in the sealant before deciding on a product. Choose a low-VOC or VOC-free alternative to protect the environment from harmful runoff while keeping wooden structures and furniture safe.
Our Top Picks
This list of some of the best exterior wood sealer products was selected based on type, transparency, water resistance, UV resistance, ease of application, environmental impact, and overall value in order to help you find the best wood sealer for your deck, fence, or wooden furniture.
Best Overall
Seal-Once Nano+Poly Penetrating Wood Sealer
One of the most important factors to keep in mind while searching for an outdoor wood sealer is that the wood is vulnerable to more than just water damage. UV radiation can crack and splinter wood, while heavy foot traffic can cause abrasive damage, leaving the wood susceptible to rain and moisture. This Seal-Once outdoor wood sealer is designed to protect decks, fences, and outdoor furniture from water, mold, decay, UV radiation, and abrasion.
The sealant is completely clear, allowing the natural finish of the wood to show through, so UV protection relies on the UV-stable formula. This water-based product has low VOCs, and it’s nontoxic, making it a good option for homes with kids or pets. After applying the first coat, it takes just 1 hour, on average, until the second coat can be applied. Despite the benefits this product has to offer, the price may be a deterrent for some people.
Product Specs
- Type: Water-based
- Transparency: Clear
- Resists: Water, mold, decay, UV, abrasion
Pros
- Low-VOC formula
- High water and UV resistance
- Abrasion resistance for high-traffic areas
- Ready for a second coat within 1 hour
Cons
- High price
Get the Seal-Once Nano+Poly outdoor wood sealer at Amazon, Seal-Once, or The Home Depot.
Best Bang For The Buck
Rain Guard Water Sealer
Designed for tackling larger projects on a budget, Rain Guard Water Sealer comes in a concentrated form that needs to be mixed with water at a ratio of 7:1 in order to make up to 2 gallons of wood sealer. This product has a clear finish that allows the natural color of the wood and the natural wood grain to show through, making it a great option for users who prefer the look of the deck or fence over a solid or semitransparent color tint.
The outdoor wood sealer is a water-based option that can be applied using a sprayer, brush, or roller. It is made with UV stabilizers to help reduce the damage and fading caused by UV radiation, and it dries in just 1 hour after application, so users don’t need to wait long to apply a second coat.
Product Specs
- Type: Water-based
- Transparency: Clear
- Resists: Water, mold, decay, UV
Pros
- Shows the natural color and wood grain
- UV stabilizers resist UV damage
- Concentrated formula makes up to 2 gallons of sealer
- Can be applied with a sprayer, brush, or roller
Cons
- Must be mixed before use
Get the Rain Guard outdoor wood sealer at Amazon, Lowe’s, or Rain Guard.
Best Oil-Based
Ready Seal Exterior Stain and Sealer
Many outdoor wood sealers are made with a water-based formula that is designed to dry quickly so that the user doesn’t need to worry about rain, but the longer time it takes for an oil-based sealer to dry is better for achieving a more even finish. This Ready Seal Exterior Stain and Sealer is an oil-based option that needs about 48 to 72 hours to fully cure, but the finished product makes it worth the wait, as long as the product is applied according to the manufacturer’s directions.
This semitransparent wood sealer protects exterior wood structures, objects, and furniture from water, mold, mildew, rot, and UV radiation. It can be applied in any temperature as long as the wood is completely dry, and this sealer comes in 10 color options, so users can get the look that they want instead of settling for what’s available.
Product Specs
- Type: Oil-based
- Transparency: Semitransparent
- Resists: Water, mold, decay, UV
Pros
- Comes in a range of colors
- High UV resistance
- Superior oil-based finish
- Can be applied in any temperature
Cons
- Takes longer to dry than water-based sealer
Get the Ready Seal outdoor wood sealer on Amazon or at The Home Depot.
Best Water-Based
Thompson's WaterSeal Advanced Natural Wood Protector
Rainy weather can ruin outdoor painting, staining, or sealing projects if they don’t have enough time to dry, but a water-based sealer can be the solution to the problem—these products take significantly less time to dry than oil-based sealers. Thompson’s WaterSeal wood sealer is a semitransparent option that dries to the touch in just 1 hour, providing water, mold, mildew, and wood-rot protection.
The semitransparent sealer also has mild UV resistance to reduce color fading, cracking, or splintering. One coat of sealer applied with a roller or brush is all that’s necessary to protect wooden structures or furniture from rain, sleet, and sun. Just keep in mind that this sealer will need to be reapplied after about 2 years.
Product Specs
- Type: Water-based
- Transparency: Semitransparent
- Resists: Water, mold, decay, UV
Pros
- Easy to apply with a roller or paint brush
- Low-odor, low-VOC solution
- Mild UV protection
- 1-coat formula
Cons
- Protection only lasts for about 2 years
Get the Thompson’s WaterSeal outdoor wood sealer on Amazon.
Best Solid
SaverSystems #1 Deck Wood Deck Paint and Sealer
Choose from six color options, including white, light walnut, classic taupe, dark cocoa, dark walnut, and gray to get the finish that matches the outdoor aesthetic of the home. This outdoor wood sealer goes on easily with a sprayer, paint brush, or roller and dries in just a couple of hours. This creates a waterproof barrier to prevent water, mold, and mildew from damaging or discoloring the wood.
The solid stain also protects the wood from UV radiation, including fading and peeling resistance. It has a low-odor and low-VOC formula, though users should note that the sealer needs a completely dry and clean surface in order to bond properly to the wood. Make sure to wash the wood structure or furniture and allow it to dry for about 24 hours before applying this sealer.
Product Specs
- Type: Water-based
- Transparency: Solid
- Resists: Water, mold, decay, UV, fading, peeling
Pros
- Available in 6 colors
- Solid sealer is UV-resistant
- Low-odor, low-VOC solution
- Fast-drying, water-based application
Cons
- May need multiple coats for adequate protection
Get the SaverSystems outdoor wood sealer paint on Amazon.
Best Semitransparent
SaverSystems #1 Deck Premium Semi-Transparent Stain
Intended to protect exterior objects like decks, fences, benches, chairs, and other wooden furniture from water, mildew, mold, and rot, this outdoor wood sealer is available in five color options and two standard sizes. Get a gallon of semitransparent sealer or handle larger jobs with the 2.5-gallon container. This sealer coats and protects the wood without covering up the natural wood grain.
The semitransparent solution provides moderate UV protection, and it is resistant to fading. This sealer comes in an easy-to-pour bottle, and the water-based formula can be cleaned up with soap and water to take care of any messes quickly before the sealer dries. However, it’s important to start working early on a hot day so that the sealer doesn’t dry too quickly, creating a blotchy or uneven finish.
Product Specs
- Type: Water-based
- Transparency: Semitransparent
- Resists: Water, mold, decay, UV, fading
Pros
- Several colors to choose from
- Moderate UV protection
- Natural wood grain shows through sealant
- Fast-drying, water-based application
Cons
- Water-based formula can dry blotchy or uneven
Get the SaverSystems premium outdoor wood sealer on Amazon.
Best Clear
Wolman Raincoat Clear Oil Base Sealer
A major benefit to choosing a clear finish for an outdoor wood sealer is that the natural color and grain of the wood can be seen through the protective coating. While this may not be appealing for standard lumber for a fence or deck, many pieces of wooden furniture are made with attractive wood that would be a shame to cover up.
The oil-based sealer is thick and can cover most wooden surfaces with just one coat. This is typically enough to protect the wood from water, moisture, mold, mildew, and rot. Additionally, the oil-based formula helps to reduce drying and cracking caused by UV radiation, though users will need to wait about 24 to 48 hours for the sealer to fully cure. Once dry, it has a mildew-resistant coating that helps to prevent staining.
Product Specs
- Type: Oil-based
- Transparency: Clear
- Resists: Water, mold, decay, UV
Pros
- Matte clear finish shows natural wood
- Moderate UV resistance
- Mildew-resistant coating prevents staining
- 1-coat coverage
Cons
- Long drying time
Get the Wolman outdoor wood sealer at The Home Depot or Menards.
Best Eco-Friendly
Eco Advance Wood Siloxane Waterproofer
This water-based, nontoxic, nonflammable sealer is designed to protect exterior wood structures, furniture, and other wood objects from water, mold, mildew, and rot. It can also prevent damage from oil, salts, and pool chemicals while being an eco-friendly option. Just load the sealer into a standard garden pump sprayer and then spray the target surface to apply a thick coat of Eco Advance outdoor wood sealer. However, users should also cover any vegetation, structures, or other items that they do not want sprayed before beginning.
The solution takes just a couple of hours to dry, and the finish is completely clear, allowing the natural grain and color of the wood to show through. After the initial application, users can reapply this product about once every 1 to 2 years to ensure ongoing protection.
Product Specs
- Type: Water-based
- Transparency: Clear
- Resists: Water, mold, decay, oil, salts, pool chemicals
Pros
- Nontoxic formula
- Apply with a standard garden pump sprayer
- Protects against oil, salt, and pool chemicals
- Water-based solution dries quickly
Cons
- Short protection period
Get the Eco Advance outdoor wood sealer on Amazon or at The Home Depot.
Best UV Protection
Seal-Once Marine Premium Wood Sealer
Ocean air carries salt and high moisture levels that can seep into exterior wooden structures, furniture, and objects, like a wooden swing. The water swells and warps the wood, attracting mold and mildew, while the salt dries out the wood fibers, causing it to crack and splinter. Protect exterior wooden items with the Seal-Once Marine Premium Wood Sealer that is designed to waterproof docks, decks, and other wooden structures from water, mold, decay, rot, and salt water.
The sealer is also designed with UV stabilizers to prevent fading and to protect the wood from harmful UV radiation. This product has a low-odor, low-VOC formula that is better for the environment than standard outdoor wood sealers, and it comes in three semitransparent color options as well as a clear finish.
Product Specs
- Type: Water-based
- Transparency: Clear
- Resists: Water, mold, decay, salt water, UV, fading
Pros
- Built-in UV stabilizers
- 3 semitransparent color options
- Saltwater protection is ideal for the coast
- Low-odor, low-VOC formula
Cons
- Not available as a solid sealer
Get the Seal-Once Marine Premium outdoor wood sealer at Amazon, Seal-Once, or The Home Depot.
Also Consider
Olympic Stain Smartguard Multi-Surface Sealant
If the goal is to apply the sealant quickly and get back to enjoying the day, then this may be the right product. It comes in a small 0.1-gallon container, but when the contents of this package are mixed with 2 gallons of water, there is more than enough sealer to cover up to 500 square feet. The sealer protects against water damage, rot, mold, mildew, and decay, though it doesn’t have noticeable UV resistance.
Other outdoor wood sealers are intended for use on wood only, but this product is a multisurface sealer that can also be used on masonry or composite materials. It takes just 1 hour to dry after application, but it’s important to note that the user needs a standard garden sprayer to apply this sealer. Additionally, it’s recommended to use drop cloths to protect any other objects or surfaces that should not be coated in sealer.
Product Specs
- Type: Water-based
- Transparency: Clear
- Resists: Water, mold, decay
Pros
- Designed for fast, broad application
- Mixes with water to make up to 2 gallons
- Use on wood, masonry, or composite
- Dries in just 1 hour
Cons
- Requires a sprayer for application
- Concentrate needs to be mixed
Get the Olympic outdoor wood sealer on Amazon or at The Home Depot.
Our Verdict
Protect wooden decks, fences, and furniture from UV rays, water, mold, and mildew with Seal-Once Nano+Poly outdoor wood sealer, or opt for the more affordable Rain Guard outdoor wood sealer if you don’t mind the extra step of mixing the sealer from this concentrated formula.
How We Chose the Best Outdoor Wood Sealers
Wood sealers are designed to provide a waterproof exterior layer in order to protect the wooden structure, furniture, or object to which the sealer is applied. For the purpose of putting together this list of the best outdoor wood sealers, it was necessary to conduct in-depth research into a wide range of more than 40 products.
The type and transparency were primary factors in the final decision because they affected the application, drying time, and resistances. Water isn’t the only hazard for exterior wood objects and structures. Opaque or semitransparent sealers provide UV protection and help to prevent the wood from drying and cracking.
Water-based sealers are easier to apply and clean up, though they don’t cover as well as oil-based sealers, so you may need more than one coat. Additionally, low-VOC or zero-VOC products were preferred over high-VOC sealers that could have a serious impact on the environment. Color selection, price, and quantity were also taken into consideration to choose the best outdoor wood sealers for exterior furniture and wooden structures.
FAQs
It’s beneficial to have detailed information about wood sealers to understand why it’s recommended to seal outdoor wood products. Learn more below by reading the answers to some of the most commonly asked questions about outdoor wood sealers.
Q. Why do I need to seal my wood?
The intention behind sealing outdoor wooden objects is to prevent moisture from entering the wood, causing it to swell, warp, and rot. Outdoor sealers create a waterproof layer that bonds to the wood to repel moisture.
Q. Should I seal all sides of wood?
You should seal all sides of a board or a piece of furniture, especially if all sides will be visible. Wooden objects that are installed or used outdoors should be completely sealed to help protect the item from rain, snow, and moisture. However, you don’t have to seal all sides if the wooden object is set up indoors and the bottom is largely unseen.
Q. How long does exterior wood sealer last?
On average, exterior wood sealer is made to last for about 4 to 5 years, though it may begin to show signs of wear before this point, especially if the sealant was not properly applied. Always make sure to read and follow the manufacturer’s directions for use to get the best results.
Q. Will outdoor wood sealer withstand harsh weather conditions?
The main purpose of outdoor wood sealer is to create a waterproof layer that bonds to the exterior of the wood. Some sealants will also provide UV protection, though this is primarily reliant on the transparency of the product. With this in mind, wood sealers can protect fences, decks, or wood furniture from rain, sleet, and snow, though it does nothing to help with hail or strong winds, which can physically damage the wood.
Q. Can I paint sealed wood?
It isn’t recommended to paint over sealed wood because sealants are specifically designed to seal out moisture. This means that paint or stain will not adhere to the wood, resulting in bubbling, flaking, and chipping.