You’ve just installed your brand new deck, now it’s time to make sure that it’s protected from the weather. If you leave your deck as it is, moisture will get in and cause rot. UV rays will also cause the wood to fade and crack. There are all sorts of products on the market, falling into the category of deck stain and deck sealer.
The problem is, a lot of people don’t know the difference between the two and it’s tough to know what to use. This article will clear up all of the questions you have about the difference between stain and sealer and help you decide which option is right for you.
What is Deck Stain?
Deck stain is designed to protect your wooden deck from moisture, rot, and mildew. It also has a colored pigment in it, so you can change the color of the wood. Most deck stains come in a large range of colors, some that are designed to look like natural wood and others that are not. A lot of deck stains also have additional UV inhibitors added to stop wood from turning gray in the sun.
Deck stains can be water or oil-based, with some transparent options as well as opaque stains. When applied to the wood, deck stain is designed to soak in and protect it from within, rather than creating a layer on top of the wood.
What is Deck Sealer?
Deck sealers are also designed to prevent damage from moisture, rot, and mildew. They are usually clear substances that leave the natural look of the wood intact when they dry. In fact, you can’t always tell that a sealer has been used unless you put some water on the deck to see if it beads on the top or not.
Deck sealer can be water or oil based and there are a few different types. Penetrating sealers, often made with natural oils like tung oil or linseed oil, soak into the wood. These are rubbed into the wood with a cloth and they bring out the natural grain while also protecting the wood.
You can also get coating sealers, which form a protective barrier on top of the deck instead of penetrating the wood. Products like spar urethane, shellac, lacquer, or varnish give you a hard, sometimes slightly glossy finish on top of the wood to block out any moisture. Some of these coatings will soak into the wood too. A lot of deck sealers will also contain UV inhibitors to stop the wood from being damaged by sun exposure.
What’s the Difference Between Deck Stain and Deck Sealer?
There are a few key differences between deck stain and deck sealer. Firstly, a deck stain has pigment in it, so it colors the wood. Deck sealers, on the other hand, do not contain any pigment. Some of them will alter the color of the wood slightly and bring out the darker grain, but once they dry, the wood will still retain its natural look.
The finish on the wood will look different depending on whether you use a stain or a sealer. If you use a clear coat sealer like spar urethane, you will get a solid, sometimes glossy layer on the top of the wood. A stain, on the other hand, will soak in completely and the feel of the wood will be basically the same as untreated wood.
The basic purpose of staining and sealing is the same; they both protect your deck against the elements so it is not damaged by moisture, UV rays, or mold. However, a stain is also designed to add color. Darker colored stains tend to give you better protection against the sun than a clear sealer would, so you don’t experience as many issues with fading.
In terms of longevity, wood stain may be the best option. It tends to last longer than sealer before it needs reapplying, so if you want to reduce maintenance, stain is the way to go. However, durable clear coats like spar urethane are often the exception to this rule because they’re very hard wearing.
Cost wise, stains are more expensive. They have additional ingredients in them (pigments) and they last longer, so you would expect them to cost more. However, if you consider the cost of reapplying sealer on a more regular basis, stain is just as cost-effective.
Deck Stain vs Deck Sealer Ingredients:
Deck stain and sealer may share some ingredients but there are also some key differences. The table below shows a breakdown of the common ingredients in deck stain and deck sealer:
| Ingredients | Deck Stain | Deck Sealer |
| Volatiles – The volatile is the carrier substance that delivers thet rest of the ingredients into the wood before evaporating. Common examples include mineral spirits or xylene. | Yes | Yes |
| Pigments/Dyes – Pigments provide the color. These are often made from iron oxides in various colors. Pigments are larger particles that are suspended in the volatile. Dyes, on the other hand, are smaller particles that dissolve in the volatile. | Yes | No |
| Resins – Resins are the glue that sticks the pigment together and binds it to the wood. There are many types of resin but the most common are alkyd, acrylic, and epoxy. | Yes (in water-based products) | Yes (in water-based products) |
| Additives – There are many additives present in wood stain, all with a specific function. Some are there to break up pigments and stop them from clumping, solvents can be used to further thin the stain and help it soak in more, and some prevent foaming. A lot of stains also have UV inhibitors added to protect the wood from sun damage. | Yes | Yes |
| Wood oils – Wood oils like linseed oil or tung oil can be used as a binder, and they also protect the wood against moisture. | Yes (in oil-based products) | Yes (in oil-based products) |
As you can see, the basic ingredients are very similar in deck stains and sealers. However, each product will vary slightly, especially where the additives are concerned. The major difference is that there are no pigments or dyes in deck sealer.
Do they Make Deck Stain and Sealer Combos?
Yes, you can buy deck stain and sealer combos. These products are designed to color the wood and also provide the solid top layer of protection that you expect from a sealer. They can be very effective, especially if you have an old deck that has seen better days. The stain part will soak in, revamp the faded color and offer some moisture protection. The sealer ingredients can then form a tough barrier and give a nice een finish to the wood.
Is Staining a Deck Required?
If your deck is made from pressure treated wood, you may not need to stain it right away. It has already been treated with additives to make it moisture resistant, so the stain is not necessary. You can test this by putting a bit of water on the deck. If it beads on the top you don’t need to stain the wood, but if it soaks in, it needs some protection.
You also need to stain the deck if you are unhappy with the color of the wood and you want to change it. However, staining is not the only way to protect your deck.
Is Using Deck Sealer Required?
Using a deck sealer is not required if you have used stain instead. The stain gives you the protection you need, so a sealer is unnecessary. If you are not staining the deck, you should use a sealer to protect it against the elements. If you use neither, your deck won’t last more than a few years at most because it will succumb to mold and mildew.
Do You Seal a Deck After Staining?
No, it’s never a good idea to seal a deck after staining it. For starters, it’s a waste of your time because the stain is already providing the protection that you need. Sealing over the top is just overkill. You can also ruin the finish by doing this, especially if you’re using a penetrating sealer. The stain has already saturated the wood pores, so the penetrating sealer won’t soak in properly and it will flake and peel off easily. So, pick one or the other and if you want the benefits of both, use a specially formulated stain and sealer combo instead.
Can I Use a Deck Sealer without Staining?
Absolutely, and a lot of people prefer this option. If you have invested in a beautiful redwood deck, do you really want to cover it with stain? Sealer is completely clear, so it allows you to keep the natural grain of the wood and just accent it a bit. This is the better option if you have a high-quality wooden deck. If you have previously stained the deck, make sure that you remove all of the old stain before applying your sealer.
How Do You Stain a Deck?
Follow these simple steps to stain your deck:
1. Remove old stain or sealer
If you have stained or sealed the deck in the past, you need to remove the old finish before applying new stain. If the deck is brand new, skip this step.
To remove old stain or sealer, you can scrape and sand the wood. You can also use a paint stripper or deck stripper. This is a product that you put onto your deck and then leave to soak in and work its magic for 20 minutes or so. Then, you should be able to wash all of the old stain off.
2. Wash your deck
Next, you need to wash the deck to remove any dirt and grime that could affect the finish you get from your stain. A pressure washer is a great option here but if you don’t have one, you can just use warm soapy water and a hose. If there are stubborn areas of grime, vinegar is a great natural option for cleaning or you can buy a specially formulated deck cleaner. Some people use a diluted bleach solution, but you should try to avoid using harsh chemicals where possible because this can damage the wood.
After you have thoroughly cleaned the deck, let it dry fully before applying the stain. Any residual moisture will affect how the stain goes on and the deck won’t be properly protected. Ideally, give it at least 24 hours, if not more.
3. Apply stain
Finally, you can apply your stain. It’s best to use synthetic brushes if you have a water-based stain because natural bristles will quickly absorb water and go limp. If you want to use a roller, use one with a short nap so you get an even coverage and the stain doesn’t pool up on the boards.
Use long strokes, following the grain of the wood, to avoid brush strokes. For best results, start with thin layers and apply a few, leaving time for the stain to soak in between each one. This is better than laying it on too thick and ending up with a patchy, uneven finish.
4. Let it dry and recoat
Most brands of deck stain recommend two coats for the best results. However, some products only require a single coat, so check the guidelines on the tin before you get started. Your stain should be ready to recoat after around 3-4 hours. Once it’s dry, repeat step 3 and add a second coat.
How Do You Seal a Deck?
The process for sealing a deck is relatively similar. Follow these steps for best results:
1. Prepare the deck
First, prepare the deck following the same two steps outlined above. Get rid of any old finishes (if necessary) and then give the deck a good clean. Then, let it dry fully before you move on.
2. Apply the sealer
When applying your sealer, always use a brand new brush or roller. The sealer will harden the brush or roller and if you use old ones, you don’t get a nice even finish. Use long strokes along the boards, being careful not to lay it on too thick. If you are using a penetrating sealer then you need to work it into the wood (this may take longer for oil-based products). But if you are using a clear coat that sits on top of the wood, you just need to get an even layer.
3. Let it dry and recoat
It’s important that you let the sealer dry completely before you recoat. If it is still slightly wet, it will drag and you will end up with a bumpy, uneven finish. Water-based sealers can be touch dry in a couple of hours but you should give it longer before recoating. Remember that every product is different so always check the recommended drying times.
Repeat step 2 once you are confident that the first coat is dry. Usually 2 coats is enough to give you the protection that you need but, again, refer to the guidelines on the product.
3 of the Best Deck Stains
1. Thompson’s Water Seal Semi Transparent Waterproofing Stain 
Thompson’s Water Seal is one of the most popular wood stain products on the market. It’s been around for a long while and it is always reliable. This is a semi-transparent stain, so it does contain pigment but it still lets the natural grain of the wood show through. It’s a good middle ground between a dark stain and a completely clear sealer. You have a range of different wood colors to choose from too, including acorn brown, woodland cedar, and harvest gold.
The moisture protection is excellent and it is formulated to protect against fading. It will last at least 2 years before the color starts to fade slightly. It’s simple to apply too and when you need to reapply, you can quite easily touch up faded areas without stripping back the whole deck.
2. #1 Deck Premium Semi-Transparent Wood Stain for Decks 
If you want a stain and sealer combo product, the #1 Deck Premium Semi-Transparent Wood Stain For Decks is a good choice. It will color the wood and protect it from within, while also acting as a sealer for additional moisture resistance. The best thing about it is that you can stain on damp wood, which means less drying time is needed after cleaning the deck and between coats. Once you can see that it has all soaked in and there is no stain sitting on top of the boards, you can recoat.
The consistency is thin enough to be used with a pump sprayer too, so you can quickly stain the deck and get a nice even coverage. This is ideal for touching it up after 2 or 3 years when the color begins to fade a little.
3. Cabot Semi-Solid Deck & Siding Low VOC Exterior Stain 
A lot of people want to avoid stains with lots of harsh chemicals in them. If that is a priority for you, this Cabot Semi-Solid Deck and Siding Low VOC Exterior Stain is the ideal product. It’s a water-based product made using ingredients that won’t damage the surrounding environment or release harmful fumes during the drying process. The formula is designed to improve penetration too, so you only need a single coat to get a rich color and full protection. If you want a quick and easy job, go for the Cabot stain.
RELATED ARTICLE: 10 Best Exterior Wood Stains for Outdoor Use
3 of the Best Deck Sealers
1. Thompson’s WaterSeal Advanced Natural Wood Protector 
This is another WaterSeal product and the Advanced Natural Wood Protector is just as reliable as their stain. This clear product will seal and protect your deck from moisture, giving you a long-lasting barrier. It’s water-based, so application and cleanup is easy and you only need one coat for full protection
It does give a slightly yellow tint to the wood but shouldn’t change the color too much. You will notice a slight sheen to it too, so this might not be the best option if you are looking for a completely matte finish.
2. Ready Seal Exterior Stain and Sealer for Wood
The Ready Seal Exterior Stain and Sealer for Wood is another great combination product that gives you the best of both worlds. This finish is designed to be easy to use, so it can be applied with a sprayer without the need to thin it first. The formulation stops drips and runs from forming too, so even if you are not particularly experienced with staining decks, you can’t go too far wrong. When it comes time to recoat, you don’t need to strip or sand the deck again. Simply give it a quick clean and then apply a few more coats.
It’s an oil-based, semi-transparent stain so it brings out the natural grain of the wood and seals it, while also giving it a slight tint. This is great if you have a tired deck but you don’t want to just cover it up with a dark stain.
3. Seal-Once Marine Penetrating Wood Sealer 
If you want durability, the Seal-Once Marine Penetrating Wood Sealer is the way to go. It’s a clear coat designed for protecting boats, so it is made to withstand constant contact with water and corrosive salt. So, when you put it on your deck, it will easily protect it from the elements. It soaks right into the wood and protects it from within, creating a robust waterproof seal. As soon as the first coat has soaked in, you can recoat without the need to let it dry.
If you do decide that you want some color, you can add different colored tints to the sealer. This gives you a lot more freedom because you can simply add less if you want a lighter color.
RELATED ARTICLE: 10 Best Clear Coats for Outdoor Wood
Related Questions
Do I Need to Seal the Underside of My Deck?
No, you shouldn’t need to seal the underside of your deck. It is not in direct sunlight, so it won’t crack or fade on the underside. As long as you protect the top of your deck properly so the water beads up and doesn’t run through, you should be fine. Just make sure that you get the stain or sealer right into the gaps between the boards for full protection. If the wood has been pressure-treated, it already has natural moisture resistance anyway.
The only time that you need to worry about sealing the underside of the deck is if it is open for some reason so it will be in direct rain and sunlight.
Should I Pressure Wash my Deck Before Applying Stain or Sealer?
Yes, pressure washing is one of the easiest ways to clean the deck and strip off any old finish. If your deck is made from softwood, be careful with the pressure because you could damage it. Try to keep the pressure at 1200 psi or lower to keep the wood in good condition.
Do You Need to Seal a Painted Deck?
No, when you paint your deck, it creates its own protective barrier. Adding an extra sealer on top is not really necessary so don’t waste your time. You should be prepared to pay a bit more for a high-quality deck paint if you want the protective seal to last longer without the need for reapplication.
The Verdict – Should I Stain, Seal, or Do Both?
Ultimately, it depends what you want for your deck. If you’re looking to change the color then obviously you need to use a stain. However, if you have a beautiful natural wood deck that you spent a lot of money on, don’t cover it up with a colored stain.
A clear sealer helps you highlight the natural aesthetic and make sure that it lasts for years to come. If you want to do both for added protection, always make sure to buy a combination stain and sealer instead of using two different products because it can ruin the finish. Many sealers are colored and act like a stain, so choose accordingly!
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.