All Hands on Deck

A beautiful wood deck can contribute directly to your home’s value and to your family’s quality of life, and whether the deck is 200 square feet or 2,000 square feet, many people are passionately proud of their decks.

So why do so many homeowners let their decks become downright shabby-looking? Besides time constraints, many people are completely confused about how to maintain a deck so they avoid the project altogether. Even if you’re an old-hand at deck care, the past few years have seen changes in deck care products, making it even more difficult to stay current. .

The good news is that keeping your deck in good condition can amount to no more than an afternoon or two every couple of years, depending on climate factors and the type of products you use. (Of course, this excludes regular sweeping and hosing to remove dirt and leaves.) In fact, even a complete deck makeover can be relatively quick. Thanks to new product formulas covered later in this article, it is possible to clean, color and waterproof a 1,200-square-foot deck all in one day.

The down side to deck care is that there is no one-size-fits-all answer. The best way to clean and protect your deck depends on several variables. What kind of wood is the deck made of? What kind of deck coating have you used before? Do you want a very natural wood look or would you like to add more color? Carefully assessing your deck’s condition, knowing what needs to be fixed, and knowing how you want your deck to look, goes a long way toward a smooth and satisfactory job.

So where do you start? Deck care has two parts that go hand in hand — cleaning and waterproofing. (You may hear the word sealing as a synonym for waterproofing. Just keep in mind that either word covers a wide variety of product types and deck looks, from clear finishes to colorful stains.) Sometimes you may need to replace a board or hammer nails back in, but taking care of the cleaning and waterproofing in a timely manner actually helps reduce the need for this kind of structural repair.

Protect Against Deck-struction Water took down the Titanic, and it can take down your deck. Definitely not as quickly, but outdoors, water is wood’s worst enemy.

According to Dr. Victoria Scarborough, who has worked in research and development for Thompson’s Water Seal products for more than 20 years, Wood that has not been waterproofed will absorb rain or even water from a sprinkler, causing it to swell. As the water evaporates, the wood cells shrink. This dimensional instability, repeated over time, is what causes boards to crack or split, and nails to loosen.


Pump-up garden sprayers and paint pads both help speed application of a waterproofing product.


Scarborough adds, The speed with which this happens varies greatly depending on rainfall and temperatures, but some homeowners have noted cracks after only months. And just because you aren’t using your deck during the winter doesn’t mean it’s in hibernation. Ice and snow can wreak havoc on your deck when they melt as surely as an April shower.

Sunlight and mildew may cause cosmetic or surface changes, but they don’t affect the structural integrity of the wood. Water does. Scarborough stresses.

A common myth is that pressure-treated lumber, the most common deck wood, is waterproof. Most pressure-treated lumber resists termites and wood rot, but not water damage. A fairly recent innovation is the availability of pressure-treated lumber that comes pre-treated with waterproofer when you buy it. This is available in pine in most parts of the country. This lumber will specifically be labeled as waterproof, and you’ll pay a premium versus the price of regular pressure-treated lumber. The water repellency will be effective for at least a year, so eventually you’ll need to reapply a sealer.

One of the most common questions is How often should I waterproof my deck? The answer depends on a number of factors, from the type of original coating on the wood, to the environment in your part of the country, to the amount of foot traffic on the deck.

The maker of Thompson’s Water Seal products has long recommended the splash test. Simply splash water on your deck. If it is quickly and noticeably absorbed, and the surface darkens, then the wood isn’t waterproof. If the water beads, sits on the surface or runs off, then you’re covered.

Clean Start Cleaning your deck is a critical part of the deck-care process for several reasons. Aesthetically, it can make a dramatic difference in the results by removing years of dirt, surface wood cells that have grayed due to sunlight, mildew and dark mold, and worn coatings. While algae are green, other biological organisms like mold and mildew are dark in color, and many decks are discolored because of mold as much as because of color fading. It’s also essential to come clean before you apply a new coat of waterproofer. Soils and previous coatings can keep the new waterproofer from being absorbed properly, decreasing its effectiveness, leaving the surface sticky and preventing a nice, even finish.

Even a brand-new deck should be cleaned before being treated to remove dirt and possible mill glaze that may not be visible to the eye. Another common myth is that new wood should be allowed to season for six months to a year before being waterproofed. Scarborough says this is a recipe for damage, and new lumber should be treated within the first month, unless you’re using one of the premium types of waterproofed lumber mentioned earlier.


Cleaning your deck is much easier if you choose the right method from the start. The product decision should be based on what you need to remove:

– A general cleaner will remove dirt, mold, mildew or a clear, oil-based waterproofer that has weathered (i.e., applied at least two years ago).

– A more powerful solution is needed to remove a weathered, tinted waterproofer or a semi-transparent stain, along with the dirt and mildew. This type of product also works well to remove weathered water-based coatings.

– Redwood and cedar have natural characteristics that require special treatment to enhance beauty and waterproofing efficiency. These types of wood can darken if cleaned with many types of cleaners, so look for a product formulated specifically for redwood and cedar. If you have a weathered, tinted waterproofer or stain on your redwood or cedar deck, use a product designed to remove these coatings. Follow this with the deck cleaner and brightener to neutralize the cleaner, and bring back the wood’s color before waterproofing.

– Solid stains will need to be removed by a product labeled stain remover or stripper.

After selection, the actual application of the deck cleaner is relatively straightforward. Many cleaners are premixed and can be sprayed on. After waiting a short time (usually around 5 to 15 minutes after application), you’ll either spray off the deck with a garden hose, or scrub lightly with a synthetic broom (necessary to remove tinted waterproofers or stains), then rinse off. Read and follow the label directions. In some cases, you’ll be advised to work in small sections at a time to avoid the product drying on the wood. If you missed any spots or if there are stubborn areas, you can go back and spot treat that section.

To safeguard plants and landscaping around the deck, thoroughly saturate them with water before applying the cleaner. Cover them with heavy plastic while you’re working, then after removing the plastic, spray the area again with clean water. This will effectively dilute any residual cleaner. (Follow this same procedure when spraying on a waterproofer to avoid affecting your plants.)

When it comes to selecting and applying a deck cleaner and waterproofer, there is one critical point that can’t be stressed enough: Read the label and follow the directions listed. To save time in the store, many manufacturers have detailed product information on their web sites, making it easier to decide what you need before you go in. If you’re at all unsure whether a product will handle your needs, call the company’s customer service number to be sure. A little advance planning pays off tremendously in the end.

Another option for cleaning a deck is pressure-washing using a gas- or electric-powered machine to deliver water in highly concentrated jets that power-off dirt. Pressure-washers will remove dirt, mildew, grayed cells and all types of waterproofers or stains, but they can damage wood if the water pressure or PSI (pounds per square inch) is too high and you hold the wand too close to the surface. It’s possible to literally carve into the wood with the water, so keep the PSI under 1,200.

Don’t Forget Your Coat(ing) Act Two of your deck’s revival involves decisions based on questions of both beauty and protection. At this point, consider how you would like the deck to look when you’re finished, and how you’d like it to look a year or two from now. Whether you want your deck’s color to weather naturally to a driftwood kind of silver-gray or to a like-new wood color, will depend on the waterproofer you select. If you want to add color, you’ll have more choices.


There are four different categories of deck coatings. In the following breakdown, note the estimated length of time before reapplication is needed. Keep in mind that many different factors influence the life of a coating, from the product’s formulation and application, to weather exposure to how you use the deck.

– Clear, Multi-Surface Waterproofers. These products can be used on wood, brick, concrete and other masonry surfaces. They are primarily designed to stop water damage, but they don’t contain mildewcides, pigments or UV absorbers. Wood treated with this type of waterproofer will weather over time to a silver-gray color. This type of product will need to be reapplied every one to two years.

– Clear, Wood-Only Waterproofers. These products are specially formulated to protect wood, and will usually include agents to resist mildew and color fading in addition to waterproofing. They may subtly enhance the existing color of the wood, but they won’t change it, so if you love the natural color of your wood, these are good choices. No clear product will completely block the sun’s rays, but the color fading will take place gradually. These types of waterproofers typically need to be reapplied every one to two years.

– Tinted, Wood-Only Waterproofers or Toners. These products usually offer the same combination of waterproofing, fade- and mildew-resistance, but they let you add a very sheer, natural-wood color at the same time. For example, The Thompson’s Company offers a tinted wood protector in five shades: Honey Gold, Natural Cedar, Rustic Red, Nutmeg Brown and Coastal Gray. The color allows most of the wood’s grain and character to show through. Reapplication is usually needed within two to three years.

– Wood Stains. Exterior wood stains are more pigmented than the toners and come in a wider range of colors more than 100 shades are available ranging from natural wood colors to pastel whites, greens, blues, yellows and more. These stains are available in semi-transparent formulas that allow some of the wood grain to show through. Solid formulas are available that completely cover the wood grain, but allow some of the wood texture to come through. Semi-transparent stains will typically need reapplication after three years. Solid formulas can remain in good shape up to five years.

Many people think that stains and waterproofers are mutually exclusive, and wonder if they should apply a clear waterproofer over an exterior stain. Many quality exterior stains will have effective waterproofing properties, and no additional product is needed. Read the package copy to see if the stain you’re considering also offers mildew- and fade-resistance.

Paints usually aren’t considered a deck coating. Technically, you could paint a deck as long as you make sure that the label says the product will withstand foot traffic. Not all paints will withstand that kind of stress. However, paint negates most of the natural look and feel of the wood, and removing it can be a big chore.

No matter what look you want, check the label of any waterproofing product that you buy to be sure it says it passes ASTM (American Society for Testing and Materials) standards for waterproofing. Not all products labeled as waterproofers provide the same level of protection. In fact, some products on the shelf actually fail industry measurements for effective waterproofing.

The different kinds of deck coatings, from clear to solid stain, can all be found in either oil- or water-based formulas. At one point, many consumers were skeptical of the efficiency of water-based coatings, but manufacturers have made great strides in formulating these coatings to offer the same or better protection than their oil-based counterparts. Based on the additional benefits water-based formulas offer, it’s understandable that the consumer demand for water-based formulas is steadily growing stronger. New regulations involving air quality and emissions from paints and related coatings are also furthering the drive to more environmentally friendly water-based coatings.

Waterproofing Wisdom Most deck coatings today only require one coat, but you can choose different ways to get that coat on your wood. Most clear and tinted waterproofers can be applied with a brush, roller or pump-up garden sprayer. Obviously, the sprayer greatly reduces your bending and stooping, and speeds up the application process. (Sprayers are available in a wide range of styles, but you should be able to get one that’s adequate for this job for less than $20.) Stains should not be applied in a pump-up garden sprayer, as the higher pigment loads can cause clogging. For most formulas, you can also use a compression-driven sprayer, at a low setting. With any type of sprayer, back-brushing (with paint pad or brush) may be required to even out the finish.

A great tool for applying any kind of deck coating, from clear to solid stains, is a paint pad. A paint pad goes on the end of a long handle, much like a mop. It eliminates the bending needed for a brush or roller, while giving you a great deal of control and precision over the product application for the best finish and performance.


Deck-orative Options
If you want to spend a little more time applying your waterproofer, it’s possible to create fun patterns and distinctive designs. It can be as simple as leaving the center of the deck clear (protected by a clear waterproofer) and creating a border with one of the tinted shades, or as elaborate as creating a faux rug using three (or more) shades of waterproofer applied in alternating blocks. Just don’t attempt to coat the entire deck with one waterproofer, and then apply a second color over it. Apply each different type/color of waterproofer to bare wood.

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