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Best Outdoor Wood Sealers – Reviews and Buyer’s Guide

Top Pick – The Best Outdoor Sealer

Photo: Amazon

Thompson’s WaterSeal is a trusted brand. Its Clear Wood Protector provides the strongest protection against harmful conditions for your outdoor decks and wooden projects. Thompson’s guarantees satisfaction.

Provides the strongest protection against harm conditions for your outdoor decks and wooden projects. Thompson’s guarantees satisfaction.

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Wood has always been mankind’s favorite building material, but it has always had one major problem. Because it is an organic material, wood will always rot, whether sooner or later. That’s a natural problem, but the modern world has provided an elegant and convenient solution.

I am talking, of course, about the various wood sealers on the marketThompson’s Waterproofing Wood Protector is my top pick which ensures that the project you’re working on maintains its integrity for a long time.

Below, I’ve listed the top 12 outdoor wood sealers to help you choose which one is right for your outdoor wooden project. So, let’s take a quick look at my top picks.

Best Outdoor Wood Sealers in June, 2022

  Wood sealer Covers (quart) Dry time (minutes) Sheen  
1 Thompsons WaterSeal Wood Protector 100 sq ft 60 satin Check Price
2 Rainguard Sealer up to 50 sq ft 60 satin Check Price
3 Agra Life Lumber-Seal
up to 150 sq ft 30 satin Check Price
4 DEFY Crystal Clear Sealer 50 - 75 sq ft 120 - 240 matte Check Price
5 Waterlox Original Sealer 125 sq ft 24 hours satin Check Price
6 Anchorseal 2 up to 100 sq ft 60 matte Check Price
7 SEAL-ONCE Wood Sealer 62,5 - 87,5 sq ft 180 - 240 matte Check Price
8 Olympic Waterguard 62,5 - 87,5 sq ft 120 satin Check Price
9 Agra Life Clear Cedar up to 200 sq ft 45 satin Check Price
10 DeckWise Ipe Seal 500 sq ft 60-120 satin Check Price
11 Acri-Soy Sealer up to 150 sq ft 30-60 matte Check Price
12 SEAL-ONCE Wood Exotic 62,5 - 87,5 sq ft 180 - 240 satin Check Price

1. Thompsons WaterSeal VOC Wood Protector – Great Surface Compatibility for Decks and Fences

Photo: Amazon

As this is one of the cheapest sealers on my list, it gets a few points right off the bat. For those with large projects to do, this sealer offers a chance to save a few bucks. Most buyers seem to agree that it delivers everything they need in a good sealer.

Functionality without gimmicks

Several people commented on the thick consistency of this sealer. Although this makes it impossible to use in a sprayer, the thick consistency has a couple of advantages. First of all, you are unlikely to need more than one coat. Second of all, it’s very easy to apply the product to the wood. Watery products tend to run and leak a little bit.


Based on a quick look at this product’s Material Safety Data Sheet (MSDS), it may not be quite as safe and non-toxic as advertised. Some of these chemicals are a little concerning, even if this product is less harsh than most.

Some people have also complained of an oily, grimy scum being left behind after the product dries. Many of those same people said this scum was hard to remove without damaging the finish.


  • Doesn’t really change the color of the wood
  • Nice, thick consistency
  • Price is a pretty good value
  • Good functionality with no gimmicks
  • UV and mildew resistant
  • Some complain of an oily scum left behind
  • Might not be quite as safe and non-toxic as advertised

2. Rainguard Concentrate Premium Wood Sealer – Best Eco-Friendly Outdoor Wood Sealer

Photo: Amazon

This is a sealer that focuses on one thing, and that one thing is rain resistance. It seems to do a good job in this department, causing water to bead on the surface of a deck after almost a year. This is even more impressive when you consider the fact that it’s one of the cheapest items on the list.

Effective And Well-Secured

Not only does this stuff keep the rain out, but it also contains ingredients that resist mold and mildew. Those are two of the worst enemies of outdoor wood, so that’s always a handy thing. Even though this article is focused on wood, I am glad to see that this product works on other surfaces as well.

As the icing on the cake, I might mention that this product is eco-friendly and comes with a 10-year guarantee. Although there are a few conditions to this offer, it shows a high degree of confidence on the part of the manufacturer.

Mixing needed

The only problem that we can see here is the fact that this product needs to be mixed with water in a certain ratio, which is why you can make two gallons from one quart.


  • Exceptionally good water resistance
  • 10-year guarantee
  • Resists mold and mildew
  • Most inexpensive on our list
  • Works on just about any surface
  • Has to be mixed

3. Agra-Life TriCoPolymer Lumber Seal – Great Overall Clear Wood Sealer

Photo: Amazon

Here we have a sealer that focuses a lot of its attention on environmental concerns. They have made it about as safe and non-toxic as a product of this sort can ever be.

This Sealer Can Swim

While all sealers will provide a waterproof surface, this product takes it to another level. It is rated for flood resistance, which means that it can be left underwater for long periods without ruination. I find this pretty impressive, and we wonder why this feature isn’t seen more often.


Apart from the relatively high cost of this sealer, I can see one consistent complaint. At least three reviewers have complained that this product does not cure properly and remains tacky and sticky. Most have not reported these problems, however, which leads us to believe that this finish will have trouble hardening under some conditions.

  • Doesn’t require re-coating as often
  • Rated for flood protection
  • Compatible with most types of paint
  • Not very toxic or harsh at all
  • No reported issues with yellowing
  • Kind of expensive
  • Some have reported problems with curing

4. DEFY Crystal Clear Composite Deck Waterproofing Sealer – Sealer with Zinc

Photo: Amazon

This product offers a few distinct advantages that are worth examining. First of all, the whole thing is water-based. That means you don’t have to worry about toxic fumes, toxic runoff, or any other environmental concerns. Water-based compositions like this one are also much easier to clean up when you are finished.

The Zinc Factor

The advertising for this product makes a big deal about the fact that it includes zinc. Zinc is a metal that is often used for coating steel, but it also has some useful chemical properties. It helps the deck to resist both UV damage and mold/mildew. The sun’s UV rays can have a harsh and degrading effect on your deck finish, and mold and mildew are also a major problem. By keeping out more of the sunlight, this product creates an environment where mold and mildew cannot grow.

Should Last A Long Time

Perhaps the biggest selling point of this item is its increased longevity. This product will normally last a year or two longer than most other products, and this is mainly due to its large amounts of protective ingredients. The manufacturers claim that they chose only the highest-quality resins for this product, and I think they are probably honest about that.

The Downsides

I can see a few problems with this product as well. For one thing, a lot of reviewers have claimed that this product doesn’t work. I found several negative reviews that mentioned this problem, saying that they could not tell any difference after using the product. Because most users did not report this problem, I have to conclude that this product requires multiple coats in order to be effective.

That’s a little bit of a problem because this is one of the more expensive products on the list. When you are forced to use multiple coats, the price per job becomes even more. Also, this sealer doesn’t leave the same kind of super-shiny finish that we see from some others, but some users may like that.

  • Easy cleanup
  • Non-toxic
  • Includes zinc for increased resistance to UV rays
  • Also resistant to mold and mildew
  • Superior longevity
  • Somewhat expensive
  • Often requires multiple coats
  • Not a lot of shine

5. Waterlox Original Marine Sealer – Marine Grade Outdoor Sealant

Photo: Amazon

This is the only marine sealer on the list, which means that it will probably offer superior protection against water. If you don’t know what we mean, marine paints are suitable for watercraft. Thus, they are held to a much higher standard in the area of waterproofing. Some marine paints are meant to be used above the waterline only, but this one seems to be fine for general marine use.

Made From Tung Oil

This sealer is made from a natural substance called Tung oil. Tung oil was first used in ancient China and is obtained from the nut of the Tung tree. This substance falls under the category of a “drying oil,” meaning that it will dry to a hard finish (most oils do not do this). Tung oil provides a rich shine that is second to none in terms of beauty. Thus, for jobs in which appearance is paramount, this is a fine choice indeed.

The Downsides

Like many other marine paints, this one does not dry to a perfectly smooth finish. Its texture when dry is a little bit rough and lumpy. Because of this, it might not be the best choice for your deck. You will have to use a buffer (or some similar tool) if you want a smooth finish. Because of this extra work, you should not get this product unless you live in a particularly wet/humid area.

This one is also a little bit expensive. It comes in a quart can, but it’s actually more expensive than some of our gallon-size options! Because it is handmade with natural materials, we should probably expect a higher price. Still, not everyone can afford that kind of money for a sealer.

  • Made for maximum water resistance
  • Made from natural Tung oil
  • Creates a deep, rich shine
  • Good coverage
  • Can be applied over most stains
  • Usually requires buffing
  • Kind of expensive
  • Toxic until cured

6. Anchorseal 2 Green Wood Sealer – Ideal Against End Grain Checking

Photo: Amazon

Anchorseal’s sealer has been used by professionals for decades. It is most widely known to protect wood against end grain checking. End grain checking is the term given to the splinters that you see at the end of wood planks that most often happens right after the wood is cut.

Keep in mind that as long as your piece of wood has some kind of end grain on it you can use this sealer. I’ve been using this sealer on all of my green wood blanks for about a year now and I definitely like it. Anchorseal does reduce cracking by quite a bit: the sealer really cuts down on checking, it actually decreases cracking by 90%. The quality is really good and it’s totally worth it.

Anchorseal is the top choice for most contractors when it comes to fixing end grain checking; after applying 2-3 coats, you will likely never have to worry about the splintering of that piece of wood again! It is most effective when applied right after the cut is made into the wood-hence the name “Green Wood Sealer.”

How Anchorseal works

To put it as simple as possible it is just a mixture of water and wax. As the sealer dries the water evaporates leaving a nice solid wax film over the end grain. It’s very simple to apply – just take the sealer and brush it to the end grain.

This product is almost wax-like when dried, so it is not made for sealing all kinds of projects. For example, you’d apply it to the end of the wood on your newly constructed deck, but you wouldn’t use it to stain the entire thing.

Also, be aware that this product should only be used to seal the ends of your wood project; it is not a stain and its waxy texture is not the right fit for areas that you’d walk on or frequently touch. It will also likely darken whatever wood that you apply it to, though it does dry clear.

So Anchorseal is a great solution to protect your wood against end grain checking. I’ve never had any problems with it.

  • Does a fantastic job of sealing end grain checking
  • Inexpensive
  • Once multiple coats are applied, no touch-ups are needed
  • Does not dry quickly
  • Not appropriate for larger project finish, like a deck or furniture

7. SEAL-ONCE NANO+POLY Penetrating Wood Sealer – Long-Lasting Exterior Sealer

Photo: Amazon

This is a premium wood sealer, which means that its maker has put a little more effort into its quality. Of course, it also makes for a higher price, but that’s perfectly normal.

Meant For Long-Term Use

This product earns its asking price by providing a longer lifespan than most other sealers. While most sealers will need to be re-applied every 1-3 years, this one is supposed to last 6-10 years. That’s quite impressive, but we aren’t sure if this product has been around long enough to prove such a claim. The manufacturer promises ten years for vertical surfaces and six years for horizontal ones.

The Downsides

This product will be too expensive for some people, but that’s the price of high quality. Still, I can find a few failings with this stuff. According to both the company and many customers, this sealer will allow the wood to turn gray over time. While this is natural, it can result in an ugly deck. Thus, you need to add some kind of tint to this sealant unless you like the look of greyed wood.

Some people have also reported storage problems, saying that the product would separate into two layers after sitting in the can for a while. However, I’m suspicious of these claims, because such a problem could easily be solved by shaking the can.

  • Lasts for 6-10 years
  • Penetrates deeply
  • Water-based
  • Provides good scratch resistance
  • Pretty expensive
  • Allows wood to turn gray over time
  • Some have reported storage problems

8. Olympic Stain Waterguard Waterproofing Sealant – Cheap Option for Exterior Wood

Photo: Amazon

This is one of the cheapest items on my list, so it’s automatically a great option for those on a budget (as long as it works). It claims to have all the same protections that we have seen on more expensive brands, like UV protection, mildew resistance, and all the other standard perks. I do like the fact that this product is specifically designed for decks (among other jobs).

A Mix Of Traits

This product is mostly a water-based sealant, but it does contain a little bit of linseed oil. Because of this, it has a high shine to its finish. It’s much less harsh than an oil-based sealer, but it can achieve a level of sheen that is comparable to an oil-based version.

The Downsides

When we take a look at various reviews, we can see one complaint that repeats itself: This product has apparently been changed from its original form. Those who have made this complaint say that the product is much more watered-down than it had previously been. As a result, they say, the effectiveness of the product has suffered. It could be that they went too far in their desire to be eco-friendly.

Because this is a bargain product, you should expect that it won’t be quite as nice as the more expensive kinds. It won’t have those special features and perks, but it will provide basic functionality. At the same time, you will probably have to use a lot of coats because this one is a little too thin.

  • Cheap option
  • Good for untreated or pressure-treated lumber
  • Protects against UV rays and mildew
  • Shines like an oil-based sealer
  • Product may have changed
  • Some reviewers say it’s too weak

9. Agra Life TriCoPolymer Cedar-Seal – Great Product to Treat Cedar

Photo: Amazon

If you want a flat and nonreflective surface, this is the sealer to check. Some people just don’t want a shiny surface for whatever reason, and this product gives it to them with no fuss. In spite of its relatively high cost, this is a product that boasts a few advantages

The Advantages

This is a low-VOC (volatile organic compound) formula, which means it has very low toxicity. You certainly wouldn’t want to drink this stuff, but you shouldn’t have to worry about getting sick from its use. Overall, this is one of the least toxic choices we have.

I also like the fact that this sealer allows the wood to “sweat” a little bit. This keeps moisture from being trapped inside, where it will surely cause rotting. I was also surprised to learn that this stuff works in a sprayer. Most products of this type are too thick for a sprayer, so this is a significant advantage.

The Problems

I ain’t that concerned about the price, but I am concerned with something I saw in the advertising for this product. We are told that the wood will gradually turn grey if this product is used as a stand-alone coating. This can be dealt with by adding a dye to the sealer, but it’s pretty bad that this product requires that as an extra step.

  • Pretty safe for people and nature
  • Works on treated wood
  • Allows the wood to “sweat”
  • Provides a nonreflective surface
  • Can be used in a sprayer
  • A little expensive
  • Requires a coloring agent

10. Deckwise Ipe Seal Hardwood End Grain Sealer – Nice Waterproof Product to Protect Exotic Hardwoods

Photo: Amazon

This is a very specialized type of sealer, making it different from our other choices. This one is specifically designed to prevent cracking at the ends. When a piece of wood begins to split, it always starts at the end, so this product can be used to stop a problem in its infancy.

Does Its Job Very Well

Whether used as an end sealer or a general-purpose sealer, this product seems to do its job very effectively. One of the most impressive things about this product is the fact that it gets about 500 square feet of coverage from a quart-sized can. This makes the product an even better bargain.

Dry Time

This one takes a full 48 hours to dry, so it’s not the one to choose when you’re in a hurry. Being wax-based, it has some slightly different properties, which could make it problematic for beginners. However, I can’t help but notice that this product offers no guarantee of effectiveness.


  • Made to prevent edge cracking
  • Very good coverage for its size
  • Non-hazardous wax-based formula
  • Easy to use
  • Soap and water cleanup
  • Needs 48 hours to dry
  • No guarantee of any kind

11. EcoProCote Acri-Soy Penetrating Sealer – Multi-Use Sealant

Photo: Amazon

This one is very different from the other sealers on my list, as it is made from soybean oil. This natural formulation makes the product a lot less toxic and a lot less stinky. You probably won’t even have to worry about a dust mask when using this stuff. For such a specialized product, its price is actually quite low.

Safe And Versatile

This product has two main selling points. For one, it’s a lot better for the environment than most other options. For another, it is said to last a lot longer. In fact, the advertising says that the finish will probably outlive you! I am skeptical of this claim, as only time will tell if it is true.

Long Dry Time

The biggest problem here is the factor of time-efficiency. This product takes days to fully dry, and some say that it can take weeks. Some of this will probably depend on your method of application, but that’s still a long delay. On top of that, this sealer has a thin consistency, so you’ll probably need multiple coats.

  • Provides a finish with exceptional longevity
  • Very safe for the environment
  • Seals any porous surface
  • Can be used below or over paint
  • Finish is very hard and durable
  • Takes 48 hours or more to dry
  • Usually requires multiple coats

12. SEAL-ONCE Exotic Sealer – Sealer for Exotic Wood

Photo: Amazon

This is a water-based wood sealer from SEAL-ONCE, and there are several good things about that.

Non-Toxic, Long-Lasting, And Crystal Clear

First of all, you won’t really have to worry about choking your guts out from the fumes, as this product is pretty mild. You wouldn’t want to go sticking your nose in the can, but its odors aren’t that bad at all.

This product is specifically formulated for use on hardwoods, especially tropical hardwoods like teak and mahogany. These woods are so expensive that you would be crazy to leave them uncoated. If your target object is made of oak or walnut, you should see excellent results as well.

The Problems

There is no self-leveling feature with this product, and I can tell the difference. It’s not a huge difference, but it is a little harder to avoid putting brush strokes in the final finish. Obviously, these strokes will have to be buffed out (which is a pain), so be a little more careful when you use this sealer.

I should also mention that this product isn’t the best choice for softwoods. It is made for harder woods and may raise the grain of softer woods. By the time it dries, the wood has had time to absorb a lot of water, locking it inside forever as the sealant dries.

  • Great for hardwoods
  • Eco-friendly and non-toxic
  • Provides deep and lasting protection
  • Does the job in one coat
  • Does not change the appearance of the wood
  • Not well suited for soft woods
  • A little bit hard to level

Buyer’s Guide

The sealers listed above should give you a much better idea of what is available. Now it is time to cover some general information about wood sealers so that you can get a better idea of what you need.


How Does Wood Sealer Work?

Like most other sealer products, wood sealers work through penetration. When you apply the product to your surface, it soaks into the wood while still a liquid. Thus, when it hardens, it hardens, fills and reinforces the surface of the wood. Depending on the porosity of your wood and the consistency of your sealer, the penetration should be pretty good.

Although there are products that combine stains and sealers, it’s important to realize that they are two different things. Stains are meant to color the wood while sealers are meant to provide moisture protection. Sealers are also distinct from varnishes, which only provide a water-resistant coating.

Types Of Wood Sealer

Like most products of this type, wood sealers are available in water-based or oil-based options. Water-based products seem to be the most popular, and there are several reasons for this fact. First of all, water-based products tend to have less odor and less toxicity. We have already seen some alternative-formulation products, and we can see that most of them are water-based.

A water-based finish will be a little bit harder, but it can sometimes give a cloudy finish that changes the color of the wood and obscures its natural grain. Still, this usually won’t happen unless you are using an expired can of the stuff. Some say the best thing about water-based finishes is their quick drying time.

Oil-based sealer products are the option for people who are a little more concerned with appearances. Oil-based finishes bring out the grain of the wood by darkening it and providing a high level of shine. When you see wood that is so shiny that it reflects the sunlight, you are probably looking at an oil-based finish.

Buying A Sealer For Outdoor Use

As you might guess from the title, this article is focused on sealers that are intended for outdoor use. Obviously, these have to be a little bit tougher than the others. They will have to tolerate all sorts of weather, and that warrants a change in the way you choose your sealer product.

Always make sure you get an outdoor sealer that offers strong UV protection. The sun’s ultraviolet rays are one of the main factors that cause your paint job to crack, peel, and flake away. Some people say that the UV radiation breaks down the finish at the molecular level, but this is false. UV radiation degrades paint and finishes by drying out the resin component.

You should also look for something that is a little more eco-friendly. You will probably be using this product outdoors, and it is almost inevitable that you will spill a drop or two. If nothing else, there will be some dripping from the end of the brush. So, unless you like having bare spots in your yard where no plants can grow, I would recommend that you either use a non-toxic sealer or seal the item indoors.

Applying Wood Sealer

As a first step, you should check the weather forecast for your area. Most sealers require somewhere between 1-3 days of curing time before their work is done. During this time, the sealer has not yet formed a hardened layer, so it is vulnerable to moisture. So, unless you want a bunch of ugly water beads trapped in the sealer, make sure you will have 2-3 days of dry weather.

The second step is to prepare the working surface. This will include a thorough cleaning with soap and water, and you might also have to remove the remnants of the old finish. If there are any other problems you want to deal with, this is the time to do so. Remember: If you put down sealer without fixing the underlying problems, those problems will be sealed in place forever.

Once your surface is clean and bare, you should lay down some plastic to protect the surrounding area from the overspray. No matter how careful you are, there will be some overspray, so make sure you cover any nearby plants that you like.

Finally, you paint the sealer onto the surface with a soft brush. Sprayers are not recommended because sealers are usually too thick for them, and rollers tend to leave too many streaks and marks. You have to be more careful about leaving streaks and marks because wood sealers will usually dry pretty fast. While this is very convenient, it also means that you don’t have a lot of working time.

Frequently Asked Questions

Yes, Oils are suitable for waterproofing wood. Using a paintbrush, apply an oil finish to the wood, such as linseed oil or tung oil. Allow the oil to absorb and dry overnight before inspecting the coat. Apply a second (or even third) layer, if the depth of the oil finish isn’t to your liking. Allow two or three days for it to cure.

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Yes, you can seal wood naturally by using 100% all-natural Tung oil or 100% all-natural linseed oil. They will take 2-4 days to completely dry and might need multiple applications for protection against moistures.

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Yes, you can paint sealed wood. However, you must first prepare it properly. There are a few options for preparing sealed wood for fresh paint, but we like to use an oil-based primer. On sealed wood, the oil-based primer will adhere without any problems. After that, you may use latex paint to cover it up. All things considered, it’s a really simple procedure.

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New wood needs to be sanded to encourage the opening of the pores. If the wood was previously finished and you want to rejuvenate it, you’ll need to sand it down before applying the sealant. Before applying a sealer, all old wax or oils must be removed (even oils from the hands), and the surface must be sanded until it is completely dull with fine sandpaper. This will give the new sealer a good hold and prevent it from peeling off.

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The short answer: No, sealing wood will not make it completely waterproof. The long answer: Yes, sealing wood can make it entirely waterproof, but it takes numerous applications of sealer to make it entirely waterproof. The sanding and recoating procedure requires a great deal of patience and attention to detail.

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Varnish is a great sealer for making wood coasters waterproof. When compared to other finishing solutions, it has a high solids ratio. Spar varnish can be used to protect the coasters from scratches, as well as to waterproof them. You can also consider using Polyurethane, which has both water or oil-base. Oil-based polyurethanes are more durable, but they can also give a slight tint to the look of the coasters. Polyurethane coats can protect coasters from heat, which is especially useful if you use them to hold coffee or other hot drinks. One downside of polyurethane is it takes a long time to cure.

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The life of a seal on wood depends on different factors like the type of sealant, environment, no of coats, preparation before application. When all things considered well-done and in an ideal conditions seal should last 2 to 3 years.

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Nothing lasts forever, and a wood sealer is no exception. It is generally recommended that you re-seal your deck every 1-3 years. Of course, that’s a big range, so you should think about your conditions and materials when choosing a re-sealing schedule. Obviously, areas with more rainwater and harsher weather conditions will cause sealers to deteriorate more quickly.

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The usual way to apply a wood sealer is to use a brush. You should use a soft brush and spread it onto the surface, just as you would do with paint. It is recommended to use fast, brisk strokes because this stuff usually dries pretty quickly. Before you get started, it is important that you give your deck a good washing. Any dirt or debris that might be present will prevent the sealer from adhering to that spot. Thus, there will be a weak point in your deck’s protective armor. It’s also important to protect adjacent areas from any potential overspray.

In many cases, you will need to do some basic restoration before you can apply your wood sealer. If the deck is damaged in any way, a sealer will only trap the problem inside. First, go over the surface of the deck and drive any raised nails that you might see. As wood swells and contracts, it pushes the nails upward. That creates snags and will ruin the nice flat surface that you need. Use a hammer and punch so that you don’t have to strike the surface of the wood.

It will also be necessary to remove any remnants of the previous finish. These little bits of peeling paint will keep your sealer from doing its job, so all of it has to go. This can most easily be done using a pressure washer. If that doesn’t take care of the problem, your next step should be to apply a deck cleaning solution. If this is done, be sure to wet the grass and plants around your deck thoroughly. That way, any runoff will be diluted and made weaker. If you don’t do this, it’s very easy to kill your grass.

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Polyurethane is fully inert and safe for people. Although the polyurethane finish is harmless once it has dried and cured, the finish emits potentially dangerous compounds into the air throughout the drying and curing process, a process known as off-gassing. It is not advised to sleeping in a house with uncured polyurethane.

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Yes, we can seal wood without darkening it by using a water-based polyurethane sealer. Water-based polyurethane goes on clear, dries faster, and has almost no odor. Using a tiny brush, foam pad, or cloth, apply a very thin coat of polyurethane. To prevent raising the grain, work with it and don’t use too much polyurethane. After the first application has dried for a couple of hours, you may add a second coat.

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The result of Brush or spray can be comparable if you take time with brush strokes. You don’t have to worry about brush strokes or fibers from the brush getting into the finish when you use spray polyurethane. Sprays require a good technique to avoid drips and extra prep time to protect surfaces from overspray. It’s important to apply the polyurethane in thin layers that dry fast and don’t leave visible start and stop lines. I would suggest using what you are comfortable with, both methods have pros and cons. If you are applying Polyurethane for the first time my suggestion would be to use brush because it is beginner friendly compared to spray. Polyurethane that has not been properly cured might cause breathing issues and should be handled with care.

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Wood sealer is a plastic-based product that is used to coat wooden surfaces. This protects them from moisture and creates a smooth, transparent surface. Sealers work by penetrating the pores of the wood. When the sealant hardens, it hardens the entire surface of the wood at the same time.

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Polyurethane is essentially a plastic that is liquid until it cures, is available in both water and oil-based versions, and comes in several finishes ranging from satin to glossy. Because of its low toxicity and minimal odor, water-based polyurethane is popular. It goes on clear and dries considerably faster than oil-based alternatives, plus it doesn’t add any color. Water-based polyurethane is susceptible to heat and chemicals. It’s ideal for bookcases, desktops, and picture frames that won’t be subjected to high temperatures. Oil-based polyurethane is more durable than water-based polyurethane, especially when it comes to heat resistance, therefore it’s a smart choice for a kitchen table. Although polyurethane is frequently confused with being different then wood sealer, it is actually a form of sealer.

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Rather than applying the sealer with a brush, some people choose to use a garden sprayer as a way to deliver the sealant to its target.

You don’t want to try a paint gun because a sealant will clog the tip very quickly. A garden sprayer may also get clogged from time to time, but they are a little easier to clean. If you go with this option, I would recommend that you use a brush for the railings. The garden sprayer should work fine for the deck surface, but using it on the railings will just cause too much overspray.

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In some cases, you can find products that function as both stains and sealers. However, most people choose to use them separately. Staining and sealing are two completely different jobs that are done for completely different purposes. Stains are used to change the appearance of the deck by changing the color (or at least the shade). Sealers are generally transparent, so they don’t change the color of the wood. They do provide a nice shine, but sealers are meant to be functional rather than decorative.

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Some of the best ways to waterproof wood are: Using Oil to Waterproof Wood: Oil works best as a waterproofing solution for minor projects like treating a table or countertop. Oils are easy to apply and will protect against moisture. Tung oil and Linseed oil are the basis of modern hand-rubbed oils. Its protective characteristics aren’t as long-lasting as varnishes, but it’s popular for bringing out the character of wood with a pleasantly contrasting shine over the grain. Using Sealant to Waterproof Wood: Sealant can prevent scratches and abrasions on tabletops. As well as waterproofing the wood, it can also prevent wooden surfaces from getting scratched. They are often a clear/transparent finish that coats the wood’s exterior surface. Sealants such as polyurethane, varnish, and lacquer give excellent waterproofing. They’re brushed or sprayed over sanded, clean wood, then softly re-sanded and re-coated when they’ve dried fully. They offer high moisture resistance compared to the oil finish. Using Epoxy to Waterproof Wood: Epoxy can be used to give wood a waterproof and durable coating. It’s a good choice for wood projects that will be exposed to water in most circumstances. However, in some circumstances, utilizing epoxy as a finish is not recommended; however, you can still get the benefits of epoxy by using it as a sealer before applying your finish layer. While using epoxy to seal your project will take a little longer, the extra effort will pay off in the form of an enhanced lifetime and fewer maintenance costs.

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It is a good rule of thumb to go for Heartwood while shopping for wood. Heartwood, also known as duramen, is the dead center of a tree. Its cells typically include tannins or other chemicals that give it a dark color and, in certain cases, a fragrant scent. Here are some of the wood types that excel in resisting rot: Mahogany Mahogany’s great density and hardness make it extremely resistant to water and insects. It is noted for its great strength, stability, and longevity and is one of the most resistant wood to rot. It has a delicate, visible grain that sometimes spirals. Colors can be anything from gray to brown to red to orange, or a mixture of all four. The majority of Mahogany wood used in the United States comes from three countries: Mexico, Honduras, and the Philippines. Teak Teak has been dubbed the “gold standard” in terms of decay resistance. It’s also extremely long-lasting and termite-resistant. It is highly valued for its look and durability, but it is also fairly costly. Widely grown in Africa, Asia, and Latin America. It seems to be golden to medium brown in hue, with the color deepening over time. The grain is usually straight, though it can be wavy on occasion. Black Cherry This wood is native to Eastern North America and is known for its durability and resistance to rot. It is reasonably priced wood. It is pinkish brown when freshly cut and darkens to a medium reddish brown with time and exposure to light. Except for a few curled grain patterns, the grain is usually straight and easy to work with. It has a smooth, consistent texture.

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The primary reason for sealing wood is to keep moisture out. If wood is left exposed to the elements without being sealed, it will rot. Water intrusion into wood can result in more than just fungal growth and decay. If wood freezes after absorbing water, it might crack. Water isn’t the only danger to your wood. UV rays from the sun can cause colors to fade and turn gray, and also cause wood to crack and split. One of the advantages of using a sealer on your woodworking projects is that it adds an extra layer of protection. It will hold its shape considerably better in the face of changes in the environment.

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Wood sealer may be a fairly simple product, but its purchase should be considered carefully. You might think that no manufacturer could mess up something so simple, but it does unfortunately happen. That’s why you should stick with products that have a good reputation (asking your friends is never a bad place to start, we’re also recommending checking our questions page for further consultation). I hope that we have given you a good start on this process and that you will come back again for more of my advice (you can always ask us a question directly, or comment below).

William Stewart

The proud owner and lead writer of Started writing in 2018 and sharing his love and passion for wood treatments and crafts.

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8 months ago

We are repairing a wall in a kitchen above a door where there was a water leak. We would like to treat the 2×4 framing with a wood protector – kill any existing fungus/mold and protect future dry rot – before we sheetrock. Do you have a recommendation on the best treatment for interior framing that will not have the odors of something like Copper Green?

11 months ago

Lots of good information! Still confused..putting up a Cedar outdoor pergola kit in Ga. What kind of sealer would you recommend? It gets 90-100 degrees here in the summer and down to mid 30’s during winter [infrequent]. Thanks for your insight!

11 months ago

Hi William, what would you recommend to seal/protect a laminated wood outdoor stair riser in Montana. The wood that decorates the ceiling & walls of the covered deck are Blue pine & we used Tung Oil & love the look. We did the work ourselves so we know that Tung Oil takes several coats etc. The laminates used for the stair risers were already used outside for another purpose and we purchased them second hand because they were perfect for what we wanted. We have since sanded down the weathered outside & cut them to be the stair risers but we need to seal them. We love the laminate look & don’t want to hide it. They are 5 inches wide by 18 inches deep. 2 sets of stairs so lengths vary. Should we use the Tung oil or use something else?

11 months ago

I have a cedar deck put in last fall, what is best clear sealer and I live in Minnesota

1 year ago

Hello William,

Thank you for the informative article! I am going to seal the cedar deck and wondered what is the best option to go with. The wood is pressure-treated cedar and the condition is good. There are some cracks but nothing serious. The wood has not been painted before. Our area receives a lot of rain throughout the year and it would be nice to find a sealer+stain solution that would last a few years. I am in Canada and we have Thompson, Behr, Olympic and Sico brands for stained sealers. The reason why I look for a stained sealer is because some wood is discolored (gray color) while other parts are naturally yellow.

I would appreciate your help,


Larry Jenks
1 year ago

Hi, William…

I am very happy to have found you as an informed resource for wood sealers. Many thanks for your input and suggestions.

I have been working on a problem/project for over 15 years at my home church, Calvary Baptist Church in Denver, Colorado. I was recruited for this project because I was the only architect in the congregation. We have an outdoor courtyard where we have placed our columbarium, a repository for cremains (ashes) for people from the church who have passed.

Above the columbarium, we have a pergola. The pergola consists of exposed portions of the original wood framing for what used to be a mansard roof, to which we have added some 2x10s as horizontal extensions (I would be happy to share some photos or drawings, if I can figure out a way to do that). The wood framing from the original church construction (ca. 1959) was trusses made from common wood framing materials, although I do not know the exact species. The 2×10 horizontal members we added were also common wood framing members, I believe Douglas fir.

All of the wood members were initially stained with a solid color stain 16 years ago. I do not know what that product or manufacturer was. Over time, that original coating has deteriorated, as the pergola has a southern exposure to the sometimes brutal Colorado sun. At a time when I was living in Oregon, the columbarium volunteer staff hired a young member of the church to prepare and re-coat the pergola wood. Regrettably, he did not know how to prepare the surface, or how to apply new stain. I do not know what stain he used, but it did not hold up at all. By this time, I had moved back to Colorado, and was re-recruited to help address this problem.

I met with the local architectural rep for Benjamin Moore Paints to examine our pergola and make recommendations for remediation. Since the wood was crazed and cracked, and the coating was peeling, we agreed on scraping and sanding to get back to bare wood as much as we could, and then (as I recall) priming with B-M primer for solid color stain, and re-coating with B-M Arborcoat. Decaying wood was filled with a filler recommended by our painter. That work was completed two summers ago.

Now, just this short time later, the Arborcoat has failed and we need to re-prepare and re-coat once again. I am very disappointed in the Arborcoat, as I was of the impression that it would require only minor touch-up for at least several years. Since that did not turn out to be true, we are now searching for a different product that will stand up to the weather conditions better than the Arborcoat. That is what has led us to you.

I would very much like to know what you think about our pergola, and what product(s)/procedures you would recommend. I sincerely hope that you have some time to work with us on this problem, as we are a bit uncertain about who else to ask. If you can recommend someone, I would welcome that. Many thanks in advance. If you would like photos, or to discuss this further, I can be reached at the e-mail address or phone number below.

Larry Jenks

Stacy Michalek
1 year ago

Please help me!! I’ve been reading so many sites I’m getting confused. I’m building a feral cat house and need to seal/waterproof it. So I need an outdoor, non toxic will work on plywood and last at least 3-4 yrs. Can you help me?

Bruce Cicone
1 year ago

I am using ash cladding in a bathroom. What products would you recommend for water proofing? The wood will be in a high moisture area but not in direct contact with water excepts for some droplets, mist and occasional splash.

Eileen Doss
1 year ago

I have a wooden lattice plant stand that will be manly in the house.What kind of water seal would you recommend?

will drobnick
1 year ago

hi William, i have in the past 50 years been collecting drift and other unique woods from the rivers and streams and mountains of Colorado and New Mexico. Now I am going to put these pieces together to make a waterfall/fountain. So Thanks for the wealth of your experiences with goods of the woods. I need the best sealer for submersible, soft woods that will repel molds, prevent deterioration, after dry outs. I am not worried about the color, of the evenness of the coating. But I do need something that would not change the color of the grey weathered wood. Can you advise me of the best sealant/protectant/tough finish for such a project. Thank you for your expertise.

Betty J.
1 year ago

About 8 years ago, I replaced some railway ties for retaining wall in my garden and around the window well. I was told that they were treated I would not have to apply anything but about 5 years ago, I noticed. that some of them are starting to dry and crack. I used a wood sealant and repeated treatment 2 years later. What would you recommend as a good water protectant and sealant? How often do I need to reapply?

Dawn Nunnally
1 year ago

I recently purchased a house that the deck had been painted. Maybe a few years ago, so it was in need of another coat. I repainted with an exterior high gloss paint, after caulking a few bad places, wondering what kind of sealant I can use over the paint. This was s lot of work, as its 16’x17’, and I don’t want to do it again anytime soon. What sealer can give me extra longevity? Thanks

1 year ago

Hi I have used several types of stain and oil on my decking but nothing seems ok. I have three dogs who wee on the decking so need to know what to use first an oil or a sealer . The decking has been pressure washed and is now back to basic . Now I want to coat it But where to start? Thanks

michelle Wieting
1 year ago

We have a cedar screen door which we applied 2 coats of cedar-seal two years ago. The outside is now grey and doesn’t looks bad, It faces east so it’s in the sun most of the morning. Looking to possibly stain then seal it to keep it from turning grey again. What is the best way to get the old Cedar-seal off so it can be stained, also can I use Australian timber oil to stain then seal with Cedar-seal? We live in Wisconsin so it needs to stand up to cold weather and lots of snow. Thank you.

Kim S
1 year ago

Hi, I’m reposting as my original did not seem to go through. I’m building a custom horse barn and had the builder make pine barn end doors. The doors Dave northeast and I’m in east Colorado with sun, wind, and snow/rain
I would like a medium brown stain and the best possible finish so I do t have to sand and redo annually. Also don’t want warping! What do you suggest?

Kim S
1 year ago

Hi, I’m building a barn and have double barn end doors faced on the exterior with pine. They are northwest facing but will get a morning and afternoon sun, as well as wind and rain/snow. I’m east of Denver, CO. I would like to stain and seal(?). Should I use a marine type sealer? Can you suggest a product and compatible stain? Thx!

John D.
1 year ago

So, the concrete on my little back patio, that was put in back in the 60s, had finally gotten to the point of no repair. Instead of busting it out and spending a crap-ton of money on a new slab, I put together a little deck made from pallet wood. It’s roughly an 8x10ft space and the wood is a 3/4in yellow pine. I’m at a loss to decide what product to choose, any recommendations you have would be a blessing.

keith a dewey
1 year ago

Am still sceptIcal. What is a true CLEAR oil base wood sealer? The last two that I used left a yellow tinge and only lasted (before gray set in) one year.

1 year ago

Hi, I have never done any wood work before, but I inherited an wood outdoor bench and would really appreciate your advice. I have no idea what wood the bench is made of, but I suspect that is was previously stained and varnished. The bench was outside for over 10 years with no maintenance and was flaking and the wood underneath was becoming discoulored. I have stripped off the old varnish (which took many coats on the detail areas), have sanded down the wood and am now getting ready to stain and protect the bench. It will live outdoors year round in the Pacific Northwest (rain!), and I really don’t want to have to do anything to the bench for years to come as this has been a lot of work. Based on your responses to the comments above it looks like you’d recommend the Rust-oleum marine spar varnish after the stain. I this correct, or do you have an other suggestion for this situation. thanks again for your help

alberto pulido
1 year ago

I used copper green brown on some 6×6 cedar fence posts. Can you reccomend an oil based sealer? Thank you.

Nikki Savage
1 year ago

Hi! I tried posting earlier, the page timed out & doesn’t look like it went through? I aplogize if it’s a duplicate.
I have no idea what I am doing & have been reading & rereading your reviews (which are great btw). I am still unsure about which product to use & the application. I just purchased a tabletop made from reclaimed wood, a mix of “spruce, pine, fir, etc.” that lists it as having a water based urethane matte finish. It said is not recommended for outdoor use. That is what I bought for, it will be outside year round under an open umbrella. I live in the NE, in terms of weather conditions. I figured I could just seal it and it would be ok? I don’t want to ruin the stain & texture by sanding the current finish off. Can I apply a sealer over this urethane and what product would you recommend & that will also provide UV & water protection? Thank you!

Nikki Savage
1 year ago

Hi, I have zero clue what I’m doing. I just purchased a reclaimed wood tabletop for an outdoor table under an umbrella, it’s usually always open. Listing says “mix of spruce, pine, fir, etc.”. It says it has a water based urethane matte finish & is not recommended for outdoor use. I figured I would just seal it and use it outdoors.
Can I apply a sealer over this urethane finish without sanding? I don’t want to ruin the look & stain. What product would be best to do so? Thanks!

Nikki Savage
Reply to  William Stewart
1 year ago

Thank you very much! I couldn’t find anywhere if it was ok to do that. I appreciate it!

1 year ago

We just purchased an outdoor deck dining table made from acacia wood. We want to protect it from the rain/sun. What would you recommend treating/staining it with that would be low maintenance?

Linda Biggs
1 year ago

My brother and I need to seal diy walnut board and batten siding for an enclosed front porch. The walnut was harvested off our farm and has been stacked with spacers for over ten years . One side will be planed. We live in the humid mountains of the Carolinas near Brevard, North Carolina….our average rainfall is 68″ a year.

Should I seal the ends of the boards with an end grain sealer? Because of the rainfall amount I thought about using Waterlox Marine sealer, but the Seal Once Exotic Premium Wood Sealer or Totalboat Marine Spar Varnish look promising. What would you suggest.

Thank your for your time and sharing of information.

1 year ago

Fabulous! What a great article and you really know your stuff. I have just spent a week trying to work out the best solution for my cedar external handrail. The difficulty is with some of the products, if you get it wrong you are goosed!
I have sanded off all the old product and the wood looks good but does need some colour so I will follow the instructions for the gates above. Thank you again.

Andrea Rizzo
1 year ago

We just purchased an outdoor dining table with an Arcadia wood top. It’s on a stone deck and we’ll have an umbrella up, but only when we’re using the table so it will be exposed to a lot of direct sunlight.

Can you recommend the best oil or treatment to help protect the table? It seems Tung or Linseed oil might be best but I was confused about some of the caveats with those options especially since it’s a dining table and we have young children.

1 year ago

Thompson’s water seal now has a new product teak oil .I don’t hear you mention it.I have a new pressure treated deck,what is your opinion on a sealer only?

Adair Roper
1 year ago

Hi I enjoyed your articles but I am also confused as to where to start. I have old 60 year old gates that hung outside for 30 years and then were stored in my shed for 30 years. I have re hung them at my farm entrance on an electritonic gate opener. They need to be stained and sealed or varnished. It is not a project I want to do annually. What do you suggest??

S Friedrich
1 year ago

I have an older White Mountain wooden electric ice cream maker. On the bottom of the wooden tub the glue like sealant is pealing away. I contacted the customer service department, but she was unable to recommend a solution. I found your website, and hope you have some suggestions. Thanks

1 year ago

Thank you for the informative brush-up, William. Possibly related follow-up question that i’ll attempt to make short… Finished rapidly greying salvaged wood planks (unknown type) with basic floor poly and need a recommendation for a sealant that wont advance the greying of the wood if possible. Thanks much.

1 year ago

Hi: Your article was very informative; however, I still am alittle confused as to what to use. I have a cedar 10×12 gazebo. I recently discovered that I have carpenter bees!! Never heard of them but found that they are quite common. I have treated the carpenter bees but have been told that I should seal my gazebo because they don’t like the “smell of the sealer and therefore, wont come back. Which sealant do you recommend? I definitely don’t want the graying….the wood is a beautiful natural color. HELP!!

Karen Schmidt
1 year ago

Hi. I used Thompson’s water seal on a cedar porch swing. Do you know what I can do to either get rid of the oily feel or what I could paint over it with to stop the oily feel? Thanks much.

1 year ago

Removed paint from DF siding on 1920s home. What can i apply to condition or preserve wood before oil base primer?

Paul Sangree
1 year ago

WARNING – Thompson’s water seal in aerosol spray cans has been recalled by the manufacturer because the product reacts chemically with the metal can, which could result in the can rupturing spontaneously. Since the product is highly flammable, this could result in an explosion if it is stored near a fire source. See Note that only the aerosol spray form of the product is impacted by the recall.

Jamie Coe
2 years ago

What’s your choice of sealer for a wood chicken coop? The description says the wood used is Fir. Thanks

2 years ago

Wonderful post. Thank you!

I’m a woodworking noob. As a very simple starter project, I’m building my own desk by buying metal table legs and buying a kitchen countertop (

The countertop is unfinished, and I need to finish it. What’s the best sealer to use to protect acacia wood for a home office desk?

2 years ago

Very good review. I have a question regarding re-coating a pressure treated deck that is two years old that was originally coated with an oil based sealer (Thompson’s I believe). Can I use a water based sealer now over the original oil based sealer or must I always use oil based sealers?

2 years ago

Hi! We just built a small deck around our hot tub and used a semi transparent sherwin williams deck stain. However we don’t feel that it water proofed the wood much. Can we put the Thompsons water proof clear over the stain we used? It was a water based stain and we put two coats.

2 years ago

Looking at Lowes website , the Thompsons bad reviews are horrible??
I have a new treated privacy fence put up today and the fence builder said to stay away from Thompson products? I went to the Lowes site and sure enough, the low reviews are bad, I’m confused on what to use.

2 years ago

Hello William, I want to know which sealers are suitable for dry wood?

Pete Hardy
2 years ago

Got a summer house that’s letting in water through gaps. Is there any sealer you would recommend to help to seal the gaps and make it water proof

2 years ago

Hi William,

If you were to seal or oil a spotted gum deck what product would you chose or recommend?

Cheers Justin

Harold S Guy
2 years ago

I have an exterior bar that I just built. It has a burnt wood finish that I would like to keep its look. What kind of sealer or polyurethane would you recommend. I would like a non yellowing clear finish that doesn’t have to be applied every year

Deb Thramer
2 years ago

I have a question, I removed the varnish, stain from kitchen cabinets and like the color of the natural wood, I was told they are birch . I do not want to stain them so what do I put on them to protect them. Do not want too much shine on them. First time doing this, how far down do I sand can I go too far? Thank you

2 years ago

Hey Guy,

I have just finished 2x spotted gum decks, I’m chasing a sealer that doesn’t not change the colour of the timber. Is it possible to get a sealer/oil that makes the deck look wet all year round? and bring the massive colour variations out in the timber. what would be the best product to help achieve this results?

Cheers Justin.

2 years ago

Hi – what would you recommend for a wooden playhouse? thanks!!

Man Y Li
2 years ago

Hi there,
Thanks for the article, good information.
We’re building a new cedar fence and looking for weather protection to extent the look and life of the wood. The Agri Life Cedar-Seal sounds great as we will have fruit plants growing next to the fence, so non-toxic is pretty important. However, since there will be plants, it won’t be easy to sand and reapply the seal. The con, “Fades faster than comparable products,” is worrying me a bit. Would you still recommend the Cedar-Seal or one of the other sealers?

Erin Salt
2 years ago

For exterior of porch with mahogany structure and screen frames (all vertical surfaces) 300 yds from salt water bay, plenty of sun and rain I’d like these characteristics: A. 1 coat application with minimal prep and pretty easy re-application in subsequent yrs; B. Won’t darken mahogany much or at all; C. Controls mildew; D. Some greying of wood ok.

We just sanded all surfaces after another product that we weren’t happy with after 2 yrs, so now we’re ready for a new better approach.

What are your recommendations?

margrette young
2 years ago

thanks for your article. i have an unusual problem. i have a large exterior dome (7 metres or 23 feet in diameter, and 11.5 feet high) made of marine ply or possibly simply plywood (5 ply).
the dome structure has 2 skins (= 4 surfaces). in addition, endgrains are exposed where circles are cut out of the main surfaces..
it needs to be protected against subtropical rain and sun. (I am in Australia)
and because it is so large and complex, i need the protective surface to last for at least 5 years, i cant contemplate re-doing it more often.
can you suggest what to use to protect from it rain and sun please?

Glenn Blakely
2 years ago

We are restoring as volunteers an outside area in washington Crossing State Park, in Pennsylvania. There are cut popular log pieces (cookies), that we would like to retain as seats. Is there a sealer that helps, all the end grains are facing up right , and in the woods.

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