Best Outdoor Wood Sealer 2020: Preserving Outdoor Wood







Best Outdoor Wood Sealer 2020: Preserving Outdoor Wood 1


DEFY Crystal Clear Composite Deck Waterproofing Sealer


Best Outdoor Wood Sealer 2020: Preserving Outdoor Wood 2

SaverSystem Wooden Deck Paint and Sealer


Best Outdoor Wood Sealer 2020: Preserving Outdoor Wood 3

Thompson's Water Seal Waterproofing Stain


Best Outdoor Wood Sealer 2020: Preserving Outdoor Wood 4

Eco Advance Siloxane Water Repellent


Best Outdoor Wood Sealer 2020: Preserving Outdoor Wood 5

Rain Guard Wood and Concrete Sealer

When we think of wood sealer, it’s usually for hardwood floors in the house, or in furniture construction for cabinets and dining room tables.

If you have an outdoor deck, one that you spent money to build and poured laborious hours into, you’re going to want to protect it.

UV rays, rainfall, and dry rot are all problems that you’ve going to face no matter what – unless you continually apply wood sealer. The best outdoor wood sealer is going to help provide an invisible shield against all these threats, help protect the natural color of the wood, and keep it intact.

When you get into chemicals like wood sealers, it’s easy to get lost in the ingredients list and wonder if you’re sapping harmful chemical properties in the soil below, or if it’s dangerous for kids and pets.

Don’t worry; we’ve taken the liberty of making this list of the five best outdoor wood sealers for you, and answer all your burning questions about them later on in this guide.

Best Overall: DEFY Crystal Clear Composite Deck Waterproofing Sealer

DEFY Crystal Clear Composite Deck Waterproofing Sealer

We all want better protection, longer-lasting decks and patios, and plenty of aesthetic appeal for years to come. DEFY made the best wood sealer for outdoor furniture, decks, and all outdoor wood (including unfinished sheds) that you can imagine.

UV rays are one of the biggest aggressors in outdoor wood degradation. They cause color loss in paint, peeling paint, as well as surface damage to wood that can make it easier for pests to nest inside, or for water to soak through its surface and cause swelling/splitting.

This is completely water-based, so you’re not going to have a horribly oily smell lingering around your home for two to three days. That’s a nice bonus, but not the reason that it topped our list.

DEFY utilizes a custom formula that includes zing nano-particle technology, which basically boils down to wood-based sunscreen. It just brings that UV protection one step further, doubling down on the protection that it offers for your outdoor wood.

Now let’s talk about waterproofing. It’s in the title, and it lasts for two years on average, although some report it lasting up to about four-and-a-half years before they notice any problems whatsoever. In a world where many of us have to reapply wood sealer annually, this is excellent news.

I cannot stress this enough: for the volume alone, the price is a steal. It tops performance in this entire category without having to upcharge by 30% like many other premium outdoor products do, and that’s fantastic. You get waterproofing, UV resistance, and mold resistance all in one gallon.

Cleaning and sealing doesn’t change the color of your wood, but it does bring out the natural color.

This sealer is translucent, so it fills in cracks and micro-divots in your wood, giving it a smooth finish and showcasing the color of the natural wood through this clear filter, making it appear fuller. The color will stay the same, but it’s like slapping an ultra high definition filter on it.

  • Volume: 1 gallon
  • UV Resistant: Yes
  • Mold Resistant: Yes

Runner Up: SaverSystem Wooden Deck Paint and Sealer

Deck Wood Deck Paint and Sealer

SaverSystem came in as a close second for the best sealer for outdoor wood furniture, but at the end of the day, it’s just a hair behind DEFY. I want to point out one big strength straight away, and that’s the fact that it’s a paint and sealer.

You have the choice between light walnut, driftwood gray, dark cocoa, and three other popular wood paint colors. You can match it to your current deck, or completely remodel your deck with it. The reason this is just a bit behind DEFY even though it’s also a paint, is that you need more to get the job done.

You can cover less deck with SaverSystem, but you’re also completely facelifting the entire deck, or your outdoor wooden furniture, or your shed, which is a completely different task than just using a sealer.

The sealer is excellent, but not perfect. It requires that the paint on top of your deck isn’t already layered in a polyurethane or sealer, because otherwise you won’t have good adhesive properties.

Your wood has to either be recently sanded and cleaned for proper adhesion, or be in the beginning stages of disrepair to ensure there’s no sealant layer on top.

A few more hoops to jump through, but nothing major. It’s water-based, so just like DEFY, there’s no oily smell just sitting like a hazardous cloud above your outdoor wood. SaverSystem also helps protect against harmful UV rays that tend to dull colors and damage the outer layer of your wood.

While I always recommend wearing proper masks while using a sealer or a paint/sealer combination, one good benefit here is that your clothes aren’t going to reek thanks to the low odor formula. Basically, you won’t have to burn your clothes after using this stuff in close proximity.

  • Volume: 1 gallon
  • UV Resistant: Yes
  • Mold Resistant: Yes

Alternative: Thompson’s Water Seal Waterproofing Stain

Thompson's Water Seal Waterproofing Stain

Stain and sealers provide a different set of benefits than other sealers on this list, but the main thing you want to focus on is the fact that it can waterproof like nothing else. It works very well to keep water damage away from your deck.

If you have an older deck with swell marks and splits, this will help to keep that from getting worse.

Thompson’s made the list for best outdoor wood stain and sealer, but it’s not perfect. It’s unclear whether or not this actually provides and levels of mold resistance, even though it reasonably should.

As a stain, it does slightly darken the color of your current outdoor wood. This has a lower price than DEFY and SaverSystem (about an 18% price difference on average), but you get what you pay for. Thompson’s is only guaranteeing five years on your deck before you have to seal it again.

Yes, I recommend reapplying sealant every one to three years regardless, but normally the guarantees on these packages are for longer spans of time. Based on widespread feedback, I don’t believe this is going to last for the full five years (which is completely fine).

Because of the stain components in this formula, it can actually help to dry moist or wet wood, so long as it’s not immediately following a rainstorm or anything like that. Ideally, you will apply it to freshly cleaned wood with good adhesion.

Last but not least, the advanced polymer compounds are what protect against color fading. If I had to point out one major strength of the formula itself (not quantity or cost), I would say the color protection is a high point.

  • Volume: 1 gallon
  • UV Resistant: Yes
  • Mold Resistant: Unclear

Alternative: Eco Advance Siloxane Water Repellent

Eco Advance Siloxane Water Repellent

I want to kick this off by saying there is no UV resistance, and that UV resistance alone is not the sole marker of a good wood sealer. After all, it’s all about sealing off the wood more than anything else: UV protection is just a great bonus.

Eco Advance is all about having a formula that isn’t as harmful to the environment, so when it eventually does wear down, it’s not poisoning the soil underneath your deck, or at the base of your fence.

It’s one of the best outdoor sealer for wood brands out there because they think of just about everything. There’s a low VOC rating, very low level of odor, and it can be used on multiple types of wood from shingles to plywood, and more.

It’s versatile, and provides about 18 months to two years of protection against heavy rainfall and water damage. With that, there’s also mold damage protection, so you won’t have to worry about it rotting from the inside out.

Mold protection is great, being environmentally friendly is great, but we also have to talk about price. Eco-friendly products aren’t cheap, and you get 1/8th the amount of many of the products on this list, for about 40% of the cost.

Quick math tells you that this isn’t wallet-friendly, but if you want to protect the environment (and your yard’s soil/grass), it’s worth the price.

For large-scale projects, you’re going to need a lot of sealer. If it’s just a sealer with no staining properties, you don’t need a whole boatload to cover a wide area.

However, for smaller decks and patios or a small wooden fence, you can get away with 16 oz containers like this and feel good about what you’re doing. Even if it takes two, then you’re just paying the average cost without a bunch of leftover product.

  • Volume: 16 oz
  • UV Resistant: No
  • Mold Resistant: Yes

Alternative: Rain Guard Wood and Concrete Sealer

Rain Guard Water Sealers

Last but not least, we have Rain Guard – an extremely concentrated wood sealer that provides some fantastic economical benefits.

You get a 32 oz container of this solution, which is intentionally diluted into two full gallons. We mark this as the best budget-friendly option, especially if you have a lot to seal.

You just built a new deck, and it looks great, but the wood isn’t sealed. You spent all the budget on the actual deck itself, so this is an afterthought (happens to a lot of us).

That’s what Rain Guard is here for. This clear solution doesn’t alter the color of your wood, but simply adds a sleek layer of coating on top to keep it all safe.

This outdoor sealer for painted wood (and unfinished wood) will help prevent surface damage from snow, ice, sleet, and rain for a maximum of five years.

I’m a firm believer in getting what you pay for, and getting this much for this price is good and all, but I would still go with the one to three year rule that you’ll see me talk about in the buying guide below.

Because this solution is rather thin, you can apply it with a paint roller to get maximum coverage. Rain Guard is designed for budgeting DIY warriors. This one container covers up to about 400 square feet of your deck and/or fences.

Most of the time, we don’t get coverage measurements, so this gives you the time to see how much you’re going to need by measuring your outdoor wood surfaces prior to purchase. Also, this has UV stabilizers to maintain coloratino of painted wood, so you won’t have to worry about sun fading over time.

  • Volume: 32 oz (concentrate; makes 2 gallons)
  • UV Resistant: Yes
  • Mold Resistant: Yes

Best Wood Sealer Buying Guide and FAQ

What is a Wood Sealer?


We’ve looked at five outdoor wood sealer reviews, what is a wood sealer?

First of all, it’s not a wood stain like many people think. Wood sealers are like painted invisible barriers between your wood and the elements, and it helps prolong their life.

For outdoor use, a wood sealer protects your deck, banisters, and railings, as well as your sheds. Wood sealers help diminish the effects of UV rays from sunlight, which commonly break down natural (and synthetic) polymers. Wood counts as a natural polymer.

I would argue that one of the most effective benefits of wood sealer is to hinder UV rays from causing damage. On top of that, a wood sealer also provides waterproofing properties to the wood it’s applied to, when done properly.

All it takes is one small lapse in coverage to invite water inside the wood, where it will do its damage and spread through the inside of the sealed wood.

While you can waterproof your wood while using it, you can also slightly change the color of the natural wood with sealer. This is a popular mechanic of wood sealer, although it’s not the primary purpose. Wood sealer can also help protect against damages caused by abrasions and scratches.

Finally, wood sealer can also help with expansion. When wood gets wet, it swells and can cause splits.

If you’ve ever looked at an old deck banister and seen different sized splits going vertically along it, that’s from constant expansion and evaporation. Wood sealer means that water isn’t seeping in and expanding, so you don’t end up with those swells and splits as time marches on.

How do You Waterproof Outdoor Wood?

Actually, there are three ways to get it done.

Wood Sealer

This has a natural waterproofing agent inside of it. Applying it, letting it dry, and then allowing it cure is all you have to do to waterproof your outdoor wood.

Tung Oil

This comes from the tung tree, and is used almost exclusively for finishing and protecting wood.

You’ll see this a lot in woodworking tutorials since it does such a great job of drying out smaller pieces of wood so they’re ready to work with. There’s a specific way you’re supposed to apply this to wood, though, so be cautious when you use it.


Polyurethane and varnish both take a while to dry, but keep a sleek, almost slippery finish.

These aren’t too popular for outdoor wood like decks, because they can completely bury the texture of wood underneath, making the deck slippery and hazardous in the right conditions.

Apart from these three methods, you can find some niche solutions, although many of them are nowhere near as effective (or they’ll cost you more).

How Long Will Treated Wood Last Outside?


It’s all about the conditions you’re in, which will drastically affect everything, but we do have some averages to pull from.

If treated right from the start, and consistently year after year, you can expect a medium-grade to high-grade outdoor deck to last you for thirty to forty years. Yes, it can last for longer than those annoying mortgage payments do.

This is dependent on you, however. If you don’t treat a deck properly, or not at all, for that matter, it might rot and become dangerous in as little as eight to ten years. Even then, it’s a bit of a stretch – it could be sooner.

Sealing your deck is infinitely more important than many of your outdoor chores.

Because these sealers don’t expire for quite some time, it’s not a bad idea to get enough to coat your outdoor wood two or three times, and just leave it in your garage or storage area in the meantime. That way, it’s not an added expense later; you can account for all of it now.

How Often Do You Need to Reapply the Coating?

Much of this depends on the region you live in. In Portland, Oregon or Boston, Massachusetts, you might need to apply this once every six months to accurately preserve your deck and outdoor wood. Why?

The cold, snow, and harsh weather changes absolutely degrade the finish on your deck.

In humid climates in places like Tampa, Florida and Savannah, Georgia, you’d be wise to consider applying this once every single year.

Humidity can also take its toll on wood sealer, and when mixed with extremely hot summers, it makes short work of the sealant. Thankfully, you don’t have to worry about a nor’easter whipping through and all that snow melting on the finish.

On average, you’re going to see recommendations on manufacturer labeling that gives a vague timeline of one to three years.

This is because they have no way of knowing where you live or how you’re going to use this, so it’s a fairly good estimate. Even if you live in ideal conditions, I wouldn’t go more than two years without applying a sealer if you need to space it out by that much.

Difference Between Wood Sealer and Wood Stain

These two are not the same thing. Depending on the specific brand you get and what they include, some stains might provide waterproofing capabilities, but rarely anything beyond that in similarity to sealers. Let’s take a look at the primary differences.


Stain is meant to stain the wood, which is the appeal of it in the first place. If you have a light-colored deck, but you’re redoing the siding to have a darker color, you would want a darker color for the deck to match, right?

Well nobody in their right mind is going to rip up a perfectly good deck. Instead, you can use stain to change the coloration without having to remodel it. Normally, wood sealer is applied in a clear coat and does not change the appearance of the wood beyond a very slight hue change.


Sealers always provide a waterproofing agent (otherwise, they wouldn’t be good at sealing), but stains do not have to include this. There are stains that include waterproofing properties, but that’s like getting an added bonus. It’s not standard.


Even if you’re using a waterproofing stain, it’s going to feel different than a sealer.

If you’ve stood on an outdoor deck with bare feet and felt the roughness of the wood on the heels of your feet, then it’s likely stained or not finished at all. If it feels slick or slightly smooth on your feet and not very much like wood, it’s likely been sealed.

It’s possible to stain and then seal if you want both properties. You can use a wood sealer or a standard polyurethane, but straight-up poly might make your deck slippery in adverse conditions, whereas sealer will have a better wood texture.

Effectively Sealing Decks and Patios

Wood sealer is a must for those of you with excellently beautiful decks, especially in new construction homes.

You can prolong the life of your deck by one to two decades if you seal it annually. Depending on your conditions and the area that you live in, you might have to do this twice per year, but even then, it’s a small price to pay for maintaining a perfect deck year-round.

Best Outdoor Wood Sealer 2020: Preserving Outdoor Wood 6


Madison Briggs is an interior home designer and master carpenter. Over the years, she’s designed wedding venues and penthouses, and helped to create the next generation of DIY warriors that can handle renovation and home improvement tasks on their own. With over 15 years of experience, a keen eye for unique style, and a plethora of creative ideas, she’s here to give you the inspiration you need to take your home to the next level.