Categories: Outdoor

The Best Deck Sealers Tested in 2023

Published by
James marcus

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For lots of folks, the deck is a place to make memories: relaxing, socializing, just enjoying life. But the elements (sun, rain, snow, and wind), as well as people partying on the surface, take their toll, wearing away at the wood and leading to cracks, splinters, fading, and rot. We knew that using a high-quality deck sealer could reduce such damage, so we wanted to find out which of today’s deck sealers were really worth buying and relying on.

We decided to test the most popular brands available. Our tests involved applying the sealers to decking boards, noting how easy they were to use, whether they repelled water, and how they stood up to the weather and normal wear and tear, such as foot traffic and ground-in sand.

The best deck sealer will protect the deck from damage while still allowing the natural beauty of the wood grain to show through. A clear deck sealer won’t reveal an uneven application, brushstrokes, or runs, unlike colored stain or solid paint, and sealing a deck successfully is a relatively easy task for the average DIYer.

Read on to learn more about choosing the best deck sealer for your surface, weather conditions, and budget—and discover how the following products earned a spot in this lineup.

  1. BEST OVERALL: Seal-Once Marine Premium Wood Sealer
  2. BEST BANG FOR THE BUCK: Rust-Oleum Varathane Ultimate Oil Based Deck Sealer
  3. PRESSURE-TREATED WOOD PICK: Thompson’s WaterSeal Transparent Wood Sealer
  4. BEST FOR WATERPROOFING: Thompson’s WaterSeal Clear Wood Sealer
  5. BEST WITH UV PROTECTION: Defy Composite Deck Sealer
  6. BEST LONGEVITY: ​​Olympic Maximum Stain + Sealant
  7. EASIEST TO USE: Eco Advance Exterior Wood Water Repellent Concentrate
  8. ALSO CONSIDER: Olympic SmartGuard Clear Multi-Surface Spray Sealer

Before Buying Deck Sealer

Before choosing a deck sealer, be sure that it’s the correct product for your needs. Sealer, stain, and paint can all protect your deck from the elements, though each one has different features.

Paint is typically a better choice on worn decks with mismatched boards or stains that won’t come off. It covers up these issues while offering an attractive uniform finish. While a clear sealer will prolong the useful life of an older, weathered deck, it won’t update the deck’s look.

Stain, like paint, changes the color of the wood. However, instead of forming a topcoat, stain penetrates the wood fibers in the same way as sealer. Stain is beneficial for evening out splotchy color while maintaining the beauty of natural wood grain.

Deck stain imparts a natural-looking wood color, but depending on the opacity, it can provide just a hint of color or completely obscure the wood grain, as paint would do. In addition, some deck sealers include a slight tint of color, and these stain-and-sealer combos are helpful for both protecting and refreshing the look of the wood.

How We Tested the Best Deck Sealers

Testing deck sealers was relatively straightforward. We brushed (or otherwise applied) two coats of each sealer on a decking board and then tested it for water resistance and scratch resistance. However, the real measure of a deck sealer is the test of time. We would have liked to test the sealers over a few years, but we had only a month to see how well they held up to the elements.

We positioned each test board outdoors to receive UV rays in a spot where it would be subject to the elements for a month. The temperature dipped below freezing at least 11 nights during the test phase. At the end of the month, we inspected each board for any signs of peeling and we tested again for water resistance.

In addition to noting how well the sealers held up, we also noted how easy they were to apply and how uniformly they covered the boards. For each test, we used a rubric to record points—the better a sealer performed in any area, the more points it received. At the end of the tests, we added the points and used them to help determine the best category for each product.

Our Top Picks

The best deck sealer should meet a user’s needs for appearance, budget, application, and drying time in addition to protecting the deck. We applied each of the following deck sealers to decking boards, noting how long it took them to dry, whether they needed a second coat, and how well they stood up to water, weather, and wear. The following deck sealers are among some of the industry leaders for maintaining wood decks, well-suited to various deck specifics. Learn the pros and cons of each product, and find out how they earned a spot on this lineup.

Jump to Our Top Picks

What to Consider When Choosing a Deck Sealer

While some types of wood, such as cedar and redwood, naturally resist damage from water and insects, the most common material for new deck construction is pressure-treated wood. Treated wood is saturated with chemicals to help it resist moisture damage, but even this type of wood is not impervious to Mother Nature if unprotected. Pressure-treated wood will eventually begin to show signs of wear, such as warping and splintering, within a few short years if it’s not protected by the right sealer.

Some sealers, but not all, are suitable for use on composite decking (decking made from wood fibers and adhesives formed under pressure). Do not apply any sealer to a composite deck before checking to see if it’s compatible.

A quality deck sealer will create a water barrier on the wood to help extend the useful life of the deck. Before buying, users should consider the type of sealer best suited to their individual needs and the specific protection the deck requires.

Oil-Based vs. Water-Based

There are water-based and oil-based deck sealers on the market. Although water-based products are the more popular choice, both types have their pros and their cons.

  • Ease of application: Oil-based sealers can be tricky to apply. If the deck isn’t completely dry when an oil-based sealer is applied, it’s likely to develop tiny bubbles or spots as the moisture tries to evaporate. Water-based sealers are safe to apply over slightly damp, though not wet, wood. Oil-based sealers are typically applied with a paintbrush, while water-based options can be brushed or sprayed onto the wood. Paint rollers aren’t common for applying deck sealer, regardless of the base.
  • Environmental concerns: Water-based sealers emit fewer toxic fumes, making them less irritating to the eyes and lungs during application and better for the environment overall.
  • Cleanup: Oil-based sealers require paint thinner or a similar solvent to clean brushes and tools after application, whereas water-based sealers wash off easily with just soap and water.
  • Durability: Particularly if the weather is extreme, water-based sealers can flake or chip over time, which is rarely a problem with oil-based sealers.
  • Preparation: When it’s time to reseal a deck, oil-based sealers are often more forgiving than their water-based counterparts. DIYers will still need to clean and prep the deck before applying either type of sealer, but oil-based products are generally a little easier to smooth on evenly over slightly rough wood or imperfections.
  • Cost: Oil-based sealers are usually less expensive than water-based products, which can cost twice as much per gallon.
  • Sheen: While water-based sealers rarely provide a finished sheen on the wood’s surface, oil-based sealers will often impart a slight sheen.

VOCs

Applying deck sealers, deck stains, or stain and sealer combo products, especially if they’re oil-based, can leave DIYers with headaches, burning eyes, or irritated nasal passages. This is due to fumes released by volatile organic chemicals (VOCs). In deck sealers, these VOCs are in the form of solvents designed to prevent sealer ingredients from separating and ensure a durable finish.

While no government regulations exist that specify the amount of VOCs permissible in deck sealers, manufacturers are constantly trying to reduce the amount of toxins while still producing quality products. The result is low-VOC and no-VOC sealers that emit fewer toxic fumes and are healthier for people and the environment.

  • Low-VOC: Deck sealers labeled “low-VOC” contain less than 50 grams per liter (g/L) of VOCs. Compare that to some high-VOC sealers containing as much as 300 g/L.
  • No-VOC: Sometimes labeled “zero-VOC,” these deck sealers contain very few—or no—VOCs. To qualify for the no-VOC label, products should contain less than 5 g/L.

Water and Mildew Resistance

If deck wood remains unsealed, moisture eventually leads to swelling, splitting, and rot. Unprotected decking boards are also prone to warping as they swell and contract with moisture variations. Deck sealer helps protect the wood from the damaging effects of moisture, including rain, snow, humidity, and sprinkler runoff.

Good deck sealers, like deck paints, may also include mildewcides, which are chemicals that kill fungal spores. In damp climates, the growth of mold or mildew on wooden decks can be frustrating because the white or black splotches are unsightly and difficult to eliminate. Those who live in a rainy or high-humidity climate should look for a sealer that fights fungus as well as moisture.

UV Protection

The sun’s ultraviolet (UV) rays can be merciless: Beating down day after day, they can damage the cell walls of all living things, including wood. That damage shows up on a wood deck as fading, cracking, and splintering. Deck sealers often provide UV protection thanks to added ingredients, such as tiny zinc particles that block harsh sun rays.

These ingredients tend to break down fairly quickly, however. This can occur even within a few months in a scorching and sunny climate. While deck sealers vary in durability, consider reapplying a simple water-based sealer each year before summer sets in to ensure optimal UV protection.

Coats

Many deck sealers require two coats for the best performance, though a few products can get the job done with just a single coat. That’s a big time-saver, although users will pay more for a single-coat sealer.

A water-based, penetrating sealer will often slightly raise the wood grain, which can lead to a rough surface feel. This happens when the moisture in the sealer causes the wood grain to swell and push upward. When the wood dries, the grain remains slightly higher in spots.

While some people may not mind the rougher texture, those who want a super-smooth finish can lightly sand the surface with 240-grit sandpaper before applying the second coat of sealer.

Cure time varies by the product, so be sure to read the instructions. Some sealers require adding a second coat before the first coat is completely dry, while others recommend waiting a specified number of hours, typically 2 to 8 hours. No pressure is necessary—just lightly rub the sandpaper over the wood. Since the first coat seals the wood, the second coat will not raise the grain, resulting in a smooth deck surface.

Drying Time

Deck sealers vary in the amount of drying time they require. Many will dry to the touch within 1 to 5 hours, but humidity levels and outdoor temperatures can affect that time range.

  • Water-based sealers: A coat of water-based sealer typically dries to the touch within 1 to 3 hours as long as the temperature is between 60 and 90 degrees Fahrenheit and the humidity is 50 percent or lower. Users can apply a second coat a few hours after the sealer is dry to the touch. Cure time (when the sealer has dried sufficiently for placing heavy furniture or walking) can be up to 24 hours.
  • Oil-based sealers: An oil-based sealer usually dries to the touch within 4 to 12 hours, and users can apply a second coat in about 24 hours. Some newer oil-based sealers contain quick-dry additives that may shorten dry and recoat time. Cure time can be up to 72 hours.

Tips for Using Deck Sealer

Applying a deck sealer is a relatively simple DIY project. In most cases, it doesn’t require a lot of time, although some prep work is necessary.

  • Clean the deck with a deck cleaner designed to remove existing dirt, grease, and grime.
  • Sand down rough spots, if necessary.
  • Apply the sealer. Application can vary depending on the product, but most deck sealers require diluting with water and spraying with a pump-type sprayer or brushing it on with a paintbrush.

FAQs

Exterior wood is subject to weathering, so a deck won’t last forever. However, DIYers can prolong the useful life of a deck and maintain the natural beauty by protecting it with a deck sealer. For those hoping to keep a deck looking its best, a few questions are to be expected to ensure a job well done.

Q. Is it better to stain or seal a deck?

It depends on the type of wood. Weather-resistant woods, such as cedar or redwood, need only a clear penetrating sealer to protect them. Pressure-treated wood will benefit from a stain and sealer combo that gives it an attractive color while preserving the wood.

Q. What is the longest-lasting deck sealer?

An oil-based deck sealer, such as Varathane Ultimate Spar Urethane Oil Based, will protect a deck for up to 5 years.

Q. What is the best waterproof deck coating?

Thompson’s WaterSeal Clear Wood Sealer is one of the best options on this list for superior protection against water damage.

Why Trust Bob Vila

Bob Vila has been America’s Handyman since 1979. As the host of beloved and groundbreaking TV series including “This Old House” and “Bob Vila’s Home Again,” he popularized and became synonymous with “do-it-yourself” home improvement.

Over the course of his decades-long career, Bob Vila has helped millions of people build, renovate, repair, and live better each day—a tradition that continues today with expert yet accessible home advice. The Bob Vila team distills need-to-know information into project tutorials, maintenance guides, tool 101s, and more. These home and garden experts then thoroughly research, vet, and recommend products that support homeowners, renters, DIYers, and professionals in their to-do lists.

James marcus

Garden Courte is a blog written by [James Marcus], a passionate gardener and writer. She has been gardening for over 20 years and has a deep understanding of plants and how to care for them. In her blog, she shares her knowledge and experience with others, providing tips and advice on gardening, plant care, and more.

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Published by
James marcus

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