How to Protect Your Deck

How to Protect Your Deck

Applying Deck Sealer to a Wood Deck

To get the most effective seal possible, thoroughly clean your deck before applying the sealer. Be sure all debris, dust, grime and mildew is removed. Check out our step-by-step guide for the best ways to clean a deck or pressure wash a deck.

Before we get into the step-by-step details of how to seal a wood deck, there are a few things to keep in mind. For starters, don’t apply deck sealer in direct sunlight as the finish will dry too quickly. The sealer needs time to adequately absorb into the wood. Also, if you have a brand-new deck made with treated wood, it’s best to hold off a few weeks to allow the wood to completely dry so the stain is more fully absorbed. Now, you’re ready to begin!

Step 1: Check the forecast

The first step in applying deck sealer is to ensure that you’ve got at least two days of dry weather with temperatures between 50-90 °F. This will ensure the best seal.

Step 2: Clear the deck

It probably goes without saying, but you don’t want to start sealing your deck with furniture, plants and other furnishings scattered about.

Step 3: Sand (if needed)

Before sealing, you may need to sand your deck to ensure that the sealer penetrates the wood adequately. Sanding is time consuming but necessary in many cases. Grab a pole or palm sander to speed up the process, making sure you sand in the direction of the grain. Always wear a safety mask when sanding to avoid inhaling sawdust.

Step 4: Remove debris

After sanding, you’ll want to ensure that the entire deck is free of loose debris. That includes cleaning between the cracks and then making sure the deck is totally dry.

Step 5: Stir sealer

Before applying the sealer, make sure to stir it. DO NOT shake. Shaking may cause bubbles to form in the finish.

Step 6: Apply sealer

Using a brush, paint roller, or sprayer, apply a thin coat over a two-to-three-board section. You can always add another thin coat later as it will apply and dry better than one thick coat.

Back-rolling may also be necessary to create the best coat possible. This requires one person to apply the seal and another person to use a roller or broom to spread puddles and work the finish thoroughly into the wood.

Step 7: Repeat & fine tune

Repeat Step 6 for the entire deck. Use a finer paintbrush to apply the sealer in difficult areas, such as cracks, railings and steps.


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Do I Have to Stain or Seal My New Deck?

Untreated and pressure-treated wood that is exposed to the elements will dry out, crack, split, twist, and discolor. Some wood has natural oils that protect them and will last a bit longer. Once the wood dries out, it is easy for insects, mold, and mildew to damage the wood. The dry wood is also susceptible to moisture damage and rot. The longer you wait to seal or stain your deck, the more damage to your investment.

Sprinkling a small amount of water on the wood is a good way to check if it is ready to be sealed or stained. If the water beads, the wood isn’t ready, but if the water is soaked into the wood, it is ready to stain or seal – a good indicator for pressure-treated wood that often ships wet. Wood that absorbs water will absorb stain or sealer for a better bond.

Sealing helps to maintain the color and smooth surface of the wood. The longer you wait, the more faded the wood will become, and the more ‘furry’ the board surface. New decks constructed of pressure-treated or SPF timber should be stained or sealed as soon as the water stops beading.

Staining a new deck will provide a more uniform color or tone to the wood, while sealing will help maintain the natural color. However, wood that is sealed will still fade over time but will continue to show the natural wood grain.

What Type of Deck Sealer Should I Use?

The type of sealer to use on your decking depends on what type of wood material you have. If you are uncertain as to what wood from which your decking is made, contact your local deck contractor for assistance, and they’ll be able to recommend the best products to use or reseal your decking for you. Many wood decks are made from pressure-treated pine wood, but other woods, like hardwoods, cedar, etc., can be used in outdoor decking.

For most wood decking, you’ll find three different kinds of deck sealers:

  • Clear Sealer—This is a completely clear sealant that waterproofs your wood without altering the natural color of the decking. These sealers rarely offer UV-ray protection that prevents aging and graying of your wood.
  • Semi-Transparent Sealer—This is a tinted sealer that will slightly alter the natural color of the wood, provide the necessary waterproofing it needs, and offer some UV-ray protection as well.
  • Solid Stain—While this works like a sealer, it also fairly opaque in its color distribution; it delivers tough waterproofing and sun protection and comes in a variety of colors.

Regardless of which sealer you choose, be sure to diligently follow the instructions for each product, as it varies between brands, and you want to make sure the sealer appropriately cures to protect your outdoor decking materials.

Step 3: Apply Sealant

Apply a thin, even coat of high-quality, mold- and mildew-resistant, waterproof sealant with UV protection, such as Woodsman® Water Repellent or Woodsman® Wood-Toned UV Wood Sealer and Protector, using a stain brush, in the direction of the boards. Don’t forget to cover corners and other difficult areas such as steps, railings, board ends and cracks. Apply two coats if needed.

Safety Alert!

Wear protective clothing, safety goggles and rubber gloves when sealing your deck to prevent skin irritation.

Helpful Tip

Do not apply sealant in direct sunlight. It will dry too quickly without absorbing into the wood.

3. Keep Your Deck Sealed

An unprotected deck will deteriorate quickly. Even though pressure treated wood resists rotting and insect predation, it will still crack and split from water exposure. The only way to protect your deck successfully over time is to apply a deck preservative. There are sealers, stains and paints on the market especially designed for deck use. Aesthetically, they look very different, but they protect wood and composite decks from moisture damage, fungus growth and ultraviolet light. Some also have built-in fire retardants.

Deck protection products are effective, but they have one big drawback: They lose their ability to protect wood over time and have to be reapplied. Usually, the more expensive the product, the longer it will last between applications, but there’s no magic bullet that will offer lifetime protection for a wood deck. The most important thing you can do to protect your investment is to reapply a wood sealer on a regular basis, typically in fall when the temperatures are stable and rain isn’t forecast for a week or more. Once a year is considered pretty standard, but newer formulations may reduce the reapplication frequency to once every three or four years — if you’re lucky.


Did You Know? If you’re planning to clean your deck with a pressure washer, you may be able to rent one from your local home improvement outlet.

How to Apply Deck Stain Sealer

Waiting nine months to a year before applying finish to a new pressure-treated-wood deck used to be standard procedure. Leaving wood unprotected lowers the interior moisture content and allows the pores to open and accept more sealer or stain. Unfortunately, it also contributes to weathering.

Instead, apply finish on a new or newly cleaned deck within a few weeks. Then apply a second coat the following year. “That second application leaves more finish in the wood. Doing it right also lets you wait two or three years before putting on another coat,” says the USDA’s Knaebe.

The one exception to finishing right away is new lumber that has a waxy buildup. This mill glaze won’t allow the finish to penetrate and any finish applied to it will peel off in a few months. You’ll know it’s there if water from a hose beads on the surface. Mill glaze can also appear as a burnished area. In either case, wait two or three weeks so the surface can weather. If water still beads up, sand lightly.

Apply the finish when the temperature is above 50°F and the weather will be dry for a few days. Follow directions; these tips apply to all products:

  • Wear eye protection and long pants and sleeves. Also wear rubber gloves, especially when using a stripper.
  • Before applying a finish or cleaner, protect surrounding vegetation by wetting it with a hose and covering it with plastic tarps. Rinse again when done.
  • Finish the top, exposed sides and — on new decks — the bottom of boards, if possible. Also coat any structural members you can reach. Future maintenance can concentrate on surfaces and end grain exposed to the weather.

Relaxing on a deck is a great way to enjoy the outdoors. The right care will prolong your enjoyment by protecting the surface of the wood for years to come.

FINISHES WITH slight pigmentation provide natural beauty and let you avoid lap marks. Look for “tone” on the label.
Photo by Bill Matthews

Best Deck Stain

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Thompson’s Stain protects wood from mildew, moisture, and UV damage. It can be applied to clean dry or damp wood and dries in approximately 2-hours. Although application by brush is recommended, a roller, paint pad, or sprayer will work too.

Clean-up is also easy with soap and water. The stain will cover between 150 to 400 ft² and last up to 3-years on horizontal surfaces and 4-years on siding and fences.

1. Know Your Deck Products

Building your deck may have been about aesthetics, but maintaining it is about following directions. Wood looks pretty indestructible, but it isn’t. When you use a power washer or opt for a particular stain or protector, you’re using powerful solvents and equipment. Deck maintenance products are designed to be used in a specific manner. Almost all of them will cause problems if they’re not applied in accordance with the manufacturer’s instructions.

It may sound hokey to reinforce the fact that you should read the instructions carefully on the products you use, but the fact is that not doing so can cause headaches you don’t want when maintaining your deck. For example, using a pressure washer against the grain of the wood can cause unsightly cut marks that won’t go away without sanding. Applying sealer in cold weather, before a rain or on damp wood could keep your deck tacky and sticky for days or even weeks — and never net you the sleek, finished look you want. What’s even worse is that any mistakes you make this year will come back to haunt you next year and the year after that. Keep it sweet and simple: Read and follow the directions every time.


Best Deck Sealers

Protecting your deck is a lot less expensive than building a new one, so don’t leave it exposed to the elements, which eventually leads to wear, rot and mildew. Take action early and often with quality deck stain and sealers to prolong your deck’s longevity.

But how do you know which are the best deck stains and sealers? Which ones can be trusted to withstand weather, wear and tear? Here are some of the best deck sealers on the market:

Thompsons Waterseal Advanced Natural Wood Protector

As one of the best water seal products available, Thompsons will go a long way to preserving your deck from mildew and water damage. It will also help with UV damage and color fading over the long term.

ECO-SAFE Wood Treatment – Stain & Preservation by Tall Earth

One of the great things about Tall Earth’s ECO-SAFE Wood Treatment is that it’s ready to use without any special pre-application prepping, as long as your deck is clean. One application is all that’s needed for protection; no need to apply multiple coats.

Rust-Oleum Coppercoat Wood Preservative

This EPA-registered deck sealer delivers all the benefits of a good sealer while also protecting your deck from termites and ants. You may notice a slight transparent green layer after application but it will fade with time.

CabotStain Australian Timber Oil Penetrating Oil

CabotStain is a high-quality sealer that will penetrate deep into even the densest types of wood, and unlike most other sealers, it can help prevent UV damage with iron oxide pigmentation.

Thompsons Waterseal – Transparent Stain

The best of both worlds, this deck stain and sealer combo provides a transparent color while creating a waterproof surface to prevent damage from mildew, rot and mold. It’s a user-friendly sealer that dries quickly after application.


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