The little wooden bridge spanning a creek in my front yard is one of the highlights of my property near Leavenworth. The kids love to drop little boats into the water and watch them float away. In the summer, it’s a great spot for picnic dinners.
But because the bridge is made out of wood, it takes a lot of abuse from the weather. Snow piles up. Rain soaks it. Hot summer sun bakes it.
To make it last, I used an outdoor wood stain to keep it protected from the elements. But like anything made of wood in the Pacific Northwest, it requires ongoing maintenance to keep it looking nice.
Most deck surfaces in the region are built using cedar decking. It’s a locally abundant wood that has a lovely appearance and is naturally insect- and rot-resistant, making it a popular choice among builders.
If properly maintained, the wood can last decades. As a contractor and decking specialist, I’ve seen some cedar decking last more than 50 years. But the key to that longevity is maintenance. You need to stain it every one to three years to keep it looking its best.
Unfortunately, this chore is commonly neglected.
Here is what you need to know to keep your wood deck properly maintained, so you can get the most life out of it.
The science of stain
What happens if you don’t stain or paint exterior wood? If the wood is new, it will have an attractive natural appearance for a short time, then the sunlight will begin to turn the wood gray. Some people like that appearance. Some even let cedar weather on purpose to give it an aged look.
But the big downside is that it simply won’t last as long.
Stain is designed to soak into the pores and attach to the wood fibers to keep out moisture and stop organics from taking hold. Once mold, algae and mildew do take hold, a deck can get slippery and feel like an ice rink whenever it rains — making it dangerous to use in the winter.
Rehabbing existing wood
Most older decks in the Pacific Northwest were built with wood surfaces, and may need some love to return them to their former glory. In many cases, the wood is still sound or just in need of some spot repair.
First, differentiate between the wood that makes up the frame of the deck (the substructure) and the wood on the surface (the decking). The frame is usually built out of pressure-treated wood and typically doesn’t need to be painted or stained (though it’s fine if you do). The decking is usually made of cedar, which does need to be treated, along with any railings and trim that are cedar or another finish wood.
Without the right prep work, you’ll be wasting a lot of time and energy. Removing the dirt, pollen and organics will allow the stain to adhere properly to the wood. At minimum, use an all-purpose deck cleaner with a mild detergent to scrub the surface.
Pressure washing isn’t recommended on soft cedar because the high pressure can damage the wood and create large gouges. Pressure washing can also create a rough surface that will need to be sanded down. If you decided to pressure-clean a deck, use low pressure and test an inconspicuous area.
Old stain may interfere with the new stain, which will lead to an uneven finish. If your new stain is from the same manufacturer as before, and the color is the same or slightly darker, a good cleaning is usually all that’s required. But if the old stain is flaking or the wood is rough in spots, some light sanding will be needed.
The preparation work becomes much more involved when you try to change something. For instance, changing from a dark stain to a light stain, switching between oil-based and water-based stain, switching between stain and paint — all of these require stripping off the old stain first. And stripping means that every square inch of old coating must be physically removed.
Some contractors may want to use chemicals to strip old stain. But consider whether you want to go this route. The technique uses toxic and caustic chemicals that are bad for the environment. And sloppy work can kill surrounding landscaping.
The results I’ve seen over the years are mixed — often chemical strippers don’t penetrate well enough, leaving an uneven appearance and unsatisfied customers. Even after chemical applications, sanding is often required.
Sanding off the old stain is an alternative way to strip a deck. If the deck is small, you can sand it by hand with an electric orbital or belt sander. I usually use 60–80 grit sandpaper and only sand enough to remove the old stain, avoiding grinding down the wood too much. Higher grits of sandpaper will make the pores too small to absorb stain. For stubborn areas, a stripping disk on an angle grinder can accelerate the work.
On larger decks, a large upright sander is often used. These frequently do more than just scuff an old layer of stain — they can shave significant amounts of wood from your surface. I’ve seen decks that have lost a half-inch of tread, so work carefully.
When using electric sanders, make sure any screws and nails are counter-sunk below the depth you will be sanding, or you will ruin the sandpaper and may damage the sander.
Staining new decks
Let’s say you just installed a new cedar deck and you want to stain it. When can you get started? It depends on how dry the wood is and how the weather looks.
There are two types of cedar sold in lumberyards. Green cedar is wood that was cut and left to dry naturally. This wood frequently has a fair amount of moisture in it, and will need longer to dry before stain will adhere.
The same goes for decks installed during the winter or those that have suffered through rainstorms. It’s really important to wait for some hot days to dry the wood before staining it. Sometimes you have to wait several months for a good opportunity.
Decking-grade cedar is usually sold as “kiln dried,” where the wood was heated in a giant oven before it was delivered to the lumberyard. You will usually see this stamped on the ends of the boards. But even kiln-dried products can absorb moisture, so be sure it’s dried out well, and avoid staining it in the direct sun.
Even if the wood is new and dry, it’s often a good idea to clean the surface with a deck cleaner before staining it. I have found that even when I’m careful, it’s easy to track footprints onto the deck during construction. Wet leaves can also create stains. Any marks that aren’t cleaned off will be permanent features under a semi-transparent finish.
Deck cleaners can darken the wood, so some contractors use a wood brightener to restore the natural appearance before staining.
In a small number of cases, the milling process on new wood will cause the pores to close up and prevent it from absorbing stain. Known as “mill glaze,” the wood will feel like it’s a little too smooth, and you’ll need to lightly sand it before you begin work.
It doesn’t take an advanced degree to stain a deck — but it does take time, patience and attention to detail.
Once the wood is prepared, use a stain brush (a large paintbrush designed for applying stain), roller or sprayer, or use a small piece of fabric for application. Use long, smooth brush strokes and overlap the wet edges before they dry.
Let the stain soak in for a few minutes and then wipe off the excess. It’s that simple.
Multiple coats don’t equal a better stain job. With semi-transparent stains, the wood has absorbed all the stain it needs after a single coat, so there’s no need to pile it on. In fact, adding too much stain is actually a bad thing — it can leave a tacky residue.
Solid stains and paint, on the other hand, will usually require more than one coat.
When you stain, work on small sections at a time of day that will allow you to finish the area before the excess stain dries. Apply the stain along the entire length of a few boards so you don’t accidentally leave uneven dried lines in the middle of a board.
Work steadily and carefully. Turbulence from your brush or roller can create bubbles in some products, so back brush while the stain is still wet.
When staining railing components, lattice or trim, I prefer to stain them before I install them. It’s more comfortable to stain these pieces on sawhorses, and you can avoid drips easier.
A huge consideration is the weather. Staining on a hot day or in direct sunlight will cause the stain to dry too quickly, making it challenging to wipe off the excess before it dries. Even worse results can occur if there is moisture in your wood. When exposed to direct sunlight, bubbles can form in the pores of the wood and rise to the surface. You have a short amount of time to wipe them off before they harden and leave unsightly circles that ruin the look of your deck.
Ideally, you want to save your staining for a warm, overcast day with stable temperatures and zero chance of rain in the forecast.
If painting the deck, the techniques are similar to other painting projects. A good coat of primer is key to adhesion. Unlike stain, several coats of paint are necessary for good coverage. And paint is a bit more forgiving to apply in warm, sunny weather.
As a deck-builder, I frequently get asked which stain customers should use. While I don’t have a runaway favorite in terms of products, there is some general advice that I give.
Stick with a name brand over a new product you’ve never heard of before. Make sure it’s designed to be used on a deck surface. Beyond that, the biggest decisions are the color, solid verses semi-transparent, and oil-based verses water-based.
Solid stains will show the texture of the wood but will obscure the wood grain and previous coats of stain. Semi-transparent has some color but will allow the wood grain to show through.
Water-based stains go on easily and the cleanup is as simple as rinsing out your brush. But they break down quickly. You will probably need to stain your deck every year if you use a water-based stain.
Oil-based stains tend to last longer, although you will still need a new coat every two to three years, depending on your location and how much abuse the deck sees. Cleanup requires the use of mineral spirits.
What color to use is largely personal preference. Stains come in myriad tint options. Generally, lighter colors break down faster than darker stains, although when darker stains begin to wear, it’s more noticeable.
Darker stains also run the risk of clashing with your siding. And once it’s applied, if you don’t like it, it’s harder to change from dark to a lighter color. When in doubt, I usually opt for a cedar-toned stain that will highlight the wood.
If you use paint, only use products designed for outdoor decks and patios. The biggest risk is that the paint doesn’t adhere to the wood and then bubbles and chips. I’ve seen a lot of decks that look terrible once the paint begins to wear. If you opt for paint, be sure to use a really good primer and quickly repair any areas that show wear.
Another option to consider is an elastomeric coating. This paint-like finish is rolled on in a thick layer that fills in holes and cracks to form a durable surface over the existing wood that stretches and contracts with the weather. It also reduces splinters and fills in any bad spots in the wood. This is nice if you want to get several more years out of an older deck and you’re not ready to rip off the old surface. A new coating can be applied as a DIY project for a fraction of the cost of replacing the decking.
Another good application for an elastomeric coating is when the decking is made from pressure-treated wood. While pressure-treated products are made to withstand outdoor use, they’re often less attractive and the boards are essentially coated in poison — not an ideal material for a deck surface. Covering pressure-treated decking with an elastomeric coating will seal it in and keep the chemicals off your family and pets.
General deck maintenance tips
To make a deck last for years, the top thing you can do is apply new stain often. But there are some other general maintenance practices that will prolong the life of your deck, as well.
KEEP YOUR DECK CLEAN AND FREE OF DEBRIS
Sweep regularly, paying extra attention to areas around deck posts; rot can occur where they connect to the decking. In tight areas, flick out larger debris with a flathead screwdriver, then blast out smaller pieces with a garden hose.
How often you’ll need to do this depends on your location. If you’re under a tree that drops copious amounts of pine needles or leaves, this may be needed several times per year.
While it may be tempting to use a pressure washer to speed up the job, you’re very likely to damage the wood.
Remove mold, mildew, dirt and pollen with an all-purpose deck cleaner, typically sold as a concentrate at hardware stores. Use a stiff bristle brush to lightly scrub the deck, then hose it off after a few minutes, taking care not to rinse it onto plants.
BUILD IT RIGHT
If you are remodeling or building a new deck, these features will help it last longer.
Decking that is spaced too tightly has a tendency to catch more debris. Over time, wood decking can swell and reduce the gaps even further. So if you’re installing new decking material, opt for healthy gaps between your boards.
Because areas where railings meets the deck often catch debris and increase rot potential, choose a railing style that uses the fewest connection points with the deck. There should also be a gap between the decking and railing, allowing you to sweep easier and letting tree litter blow away on its own.
The tops of railings are a part of a deck that often suffers the most. Choosing and maintaining a good rail cap will prolong the life of the entire railing. Composite decking, a wide piece of plastic-based material that won’t rot, can be used to create a “ceiling” for the rest of the railing.
Decks with good ventilation will dry out faster, extending the life of your deck. Avoid using solid skirting below your deck; lattice will allow airflow while obscuring what’s beneath the deck. More modern-looking, durable lattice panels, like those made by Oregon company Woodway, are aesthetically pleasing and keep out bigger animals while still allowing for good ventilation.
Jeff Layton is a contractor and deck specialist. His company Open Space Design offers coaching for DIY builders and design services for homeowners in the Seattle area.