All About Exterior Stain
This Old House decodes the differences between the various types of stain so that you can get the look you want
Spring heralds the arrival of weather warm enough for us to finally get outside and start undoing the damage winter has wrought on woodwork. Refreshing the finish on decks, fences, and siding tops the to-do list because without renewed protection against Mother Nature, wood will start to decay. In a one-two punch, sunlight breaks down the lignin that holds wood fibers together, leaving a gray surface that can't hold a finish. Then water gets in, rotting boards and shingles and, worse, potentially compromising the structures that lie beneath them.
You can safeguard wood in one of two ways: either with paint, which seals it under an opaque film, or, perhaps better, with exterior stain. The beauty of stain is that it's easy to apply, resistant to peeling, and brings out wood's texture or grain. But stain comes in a bewildering number of types. Some are as clear as bourbon; others are as milky as paint. Some form a film on top of the wood; others leave behind nothing but a hint of surface color.
Rather than waste time—or money—with trial and error in pursuit of the right stain for your job, take a look at the following pages. We translate the confusing labels, show you some of the many places stains are used, and offer tips on how to apply and maintain a finish for maximum durability. Once you make your choice and lay it on, you can rest easy, knowing that your wood is taken care of. Well, at least until next spring.
Shown: A knock-out deck starts with great wood—in this case, clear redwood protected with a burgundy-tinted penetrating stain. Behr Premium Semi-Transparent Weatherproofing Wood Stain; behr.com
These are the ingredients found in oil-based semitransparents, the most widely used stain type.
Resins and oils carry the pigments and additives into the wood fibers and shield them from water.
Pigments add color to wood and guard it from the sun's ultraviolet rays.
Additives improve finish performance and make the stain easier to apply.
Solvents thin the oils and resins so that they can easily penetrate the wood.
Oil- or Water- Based, or Both?
Waterborne acrylic stains stand up best to the sun. Oil stains penetrate deeply, even in tropical hardwoods. New, hybrid blends do both and are low in VOCs.
What Do They Cost?
Expect to pay $25 to $48 per gallon. Nontoxic "green" stains typically run from $40 to $75.
How Long Will the Finish Last?
It depends on the type. Those with more pigment last the longest: up to 7 years for a solid-color stain. Clear toners, which have the least amount of pigment, need to be reapplied annually.
When to Apply it?
Before installation, ideally, or soon after, to limit exposure to the elements. Reapply as needed, preferably in the spring.
DIY or Hire a Pro?
Most homeowners can easily apply stains using a brush or pump sprayer. For big projects that need lots of prep, consider hiring it out.
Has less pigment than a solid-color stain, so it only partially obscures the wood's grain. Leaves no surface film; can't peel. Recoat every 2 to 4 years.
Finely ground iron pigments called transoxides block the sun without obscuring the wood's grain and impart a warm tint. Leaves no surface film; can't peel. Recoat annually.
Looks like a flat paint; hides the wood's grain but not its texture. Forms a film that can peel if not properly applied. Recoat every 5 to 7 years.
Contains enough pigment to change the wood's color but not enough to obscure its grain. Leaves no surface film; can't peel. Recoat every 2 to 3 years.
Destined to turn gray and rot unless you cover it with stain.
Shown: Cabot solid color, semisolid, and semitransparent in New Redwood; Clear Solution Wood Toner in Cedar; cabot.com
Before you buy, ask yourself these questions.
What's the wood coated with now?
If it's bare, chose whichever stain you want. But if it has a film finish, it's easiest to stick with that; penetrating stains can't go over a film. Also, water-based stains will cover oil-based ones, but not the other way around.
What kind of wood do you have?
Soft woods, like pine and cedar, easily accept any penetrating stain. But only certain kinds of seed oils, such as tung or linseed, will soak into ultradense hardwoods like ipe and mahogany. Always test these woods first to make sure the finish will penetrate and dry.
How worn is it?
On older decks, unless you can sand off the top layer you'll get the best protection from a penetrating finish: a clear toner, a semitransparent, or a semisolid. Solid-color stains are best on new wood.
How much grain do you want to see?
The less pigment a stain has, the more grain you'll see, as shown on the stack of blocks at left. But the more pigment, the longer you can go before recoating.
Where is it located?
Stain on horizontal or south-facing surfaces gets more punishing UV rays than on vertical surfaces or shady north sides. To minimize maintenance, consider stains with more pigment.
These penetrating liquids seal the wood so that it won't shrink, crack, or rot. But they contain little if any pigment that prevents surface graying. One type, which typically contains wax or silicone, makes water bead up on the surface; another allows water to spread out in sheets. "Beaders" degrade quickly, usually in a matter of months; you know it's time for a fresh coat when the beading stops. "Sheeters" can last a few years. Water dries faster on sheeters and doesn't leave behind spots like a beader does, but there's no tell-tale sign that it's time for a new coat.
These finishes are friendly to the environment—and your lungs. Stains are packed with solvents to ensure that their resins and pigments penetrate wood fibers. Problem is, the solvents in most oil-based stains contain VOCs, which pollute the air and are unhealthy to breathe. Many so-called "green" stains—those containing less than 100 grams of VOCs per liter—rely on waterborne resins and pigments that behave differently than traditional oils. Here's what to expect.
Faster Dry Time
Waterborne resins dry faster than oils, so you can get out on your deck sooner. But greater care is required during application to prevent lap marks; brush the finish on no more than two boards at a time, and be sure to cover their lengths in one pass. Also, stains should be applied in the shade when surface temperatures are above 50 degrees.
Slower to Soak In
The new formulas are more durable and abrasion resistant but don't penetrate as deeply or quickly as oil, so it's easy to overapply them and leave shiny spots. To avoid this, brush out the finish to a thin, even film. Wipe off any excess immediately.
Potentially Prone to Mildew
Nontoxic stains may not contain chemicals that prevent mildew. If these fungi are a problem where you live, you'll have to add mildewcide to the stain before application.
Shown: Messmer's low-VOC penetrating oil works on dense exotic hardwoods; messmers.com. Vermont Natural Coatings is made with nontoxic ingredients, such as milk whey; vermontnaturalcoatings.com. BioShield contains no VOCs or toxic chemicals. Comes in 17 colors; bioshieldpaints.com. SafeCoat offers wood-tone colors with low odor; afmsafecoat.com
Semitransparent and solid-color stains come in scores of hues, giving your home a painted look that's a cinch to maintain. Follow along for a gallery of vibrantly stained, curb-appeal-boosting clapboards, shingles, and trim.
From a distance, this Craftsman-influenced house looks painted, but closer inspection reveals a penetrating semitransparent stain on its cedar clapboards. This no-peel finish gives wood the appearance of being dyed, a rustic look in keeping with its woodland setting. Care is minimal; just wash and a recoat every few years. Clapboard stain, similar to shown, Flood TWF-Semi in Blue Shale; flood.com
A bold trim color can highlight a house's best features. Here, a solid-color acrylic stain accents this contemporary home's intersecting walls of windows and dramatically soaring roofline. Sherwin-Williams's WoodScapes Solid-Color Stain in Cape Cod Red on trim, and DeckScapes Waterborne Semi-Transparent Stain in Cider Mill on decking and siding; sherwin-williams.com
Solid-color stains mimic the appearance of the flat, oil-based paints used since colonial times. These days, however, the best solid-color stains are made with water-based, 100 percent acrylic resins, which don't turn chalky and harden with age as oils will. They're also more permeable to water vapor, making them less likely to peel. The clapboards on this Colonial Revival–style house are finished with Cabot Pro V.T. Solid Acrylic Stain in Gray Moss; the trim is Ultra White; cabot.com
Having two types of siding offers an opportunity to use two different stains. Here, the shingles show off their russet hue under a clear toner, while the boards and battens get a low-maintenance solid-color stain. Olympic Maximum Waterproofing Sealant in Cedar Naturaltone on shingles, and Maximum Solid Color acrylic stain in Wedgwood on the vertical boards; olympic.com
Uncoated siding in coastal areas naturally turns a soft driftwood color after years of exposure to the sun and salt air. To accelerate this process without leaving siding susceptible to rot, Cabot developed a product called Bleaching Oil back in the late 1800s. Basically it's a lightly pigmented, semitransparent oil-based stain that contains a special bleaching agent. Once it's brushed onto new, uncoated softwood siding, such as cedar, fir, or cypress, the surface changes to a light gray in about 6 months to a year. Recoat every 3 to 5 years.
The wood particles in wood-and-plastic composite decking are just as vulnerable to the sun as solid wood and will turn dingy over time. Specialized semitransparent stains for composites allow you to restore or change the color of weatherbeaten decking. These last a year or two. You can also use a standard solid-color acrylic deck finish and get 3 to 5 years of service. High-traffic areas may need more frequent attention.
Shown: Messmer's Composite Deck Finish in Navajo Red; messmers.com
For a luster worthy of a fine yacht, choose a translucent film-forming finish. Spar varnish has been the traditional choice for this effect, but it's a bear to apply and maintain. Sikkens's two-coat Cetol Dek Finish (sikkens.com), shown at left, offers the same look but with a film that's more breathable and flexible, and it has more sun-blocking pigments than a varnish. Brushing on a refresher coat is easier, too. Just wash it, and apply the new finish when it dries.
As with any coating, longevity depends on good preparation and application. Professional painter Rich O'Neil offers his advice for putting penetrating stains on decks and siding.
1. Don't Delay
If you see a spot of bare wood or notice fading, get right to work. If you wait too long, you'll have to sand out the gray discoloration before you start.
Wet the wood with a hose, then apply a cleaner like Jomax. Let it sit a few minutes, then scrub with a stiff-bristle brush to loosen the dirt. Hose off the debris; don't use a pressure washer, which can gouge wood. Pull out any gunk between boards with a 5-in-1 tool. On vertical surfaces, work from the bottom up.
When the wood is dry, rough up the surface with a random-orbit or pole sander fitted with 60-grit paper. Use a leaf blower to blast off the dust.
O'Neil favors a thick, 4- to 6-inch block stain brush, like the one here, which gives him better control than a sprayer. To prevent lap marks, work on only two or three boards or courses at a time and go from one end to the other. If spraying or rolling on the finish, always go back and brush the surface.
After 20 minutes, mop up any stain that hasn't penetrated. To avoid spontaneous combustion, put stain-soaked rags in a sealed can filled with water. Dispose of the container at a hazardous-waste center.
Dilute a quart of laundry bleach in a gallon of water mixed with a cup of TSP substitute. (Used full strength, bleach can chemically burn the wood.) Brush onto the deck surface, and rinse before the solution has a chance to dry.
This occurs only on finishes that form a film, such as solid-color stains; penetrating stains don't peel. There are many causes of peeling—poor prep work, wood decay from rot or sun, water vapor getting underneath the film and lifting it, UV damage to the finish itself—but the only cure is to remove the peeling stain and start over on a sound, clean surface.
It's the inevitable effect of the sun and foot traffic, but it's also a good indicator that it's time for a new coat of penetrating stain or waterproofer. To find out, test the wood by pouring some water on a shady spot of your deck and seeing how long it takes to soak in. If the water disappears in less than 5 minutes, the wood is ready for a new coat. If a finish seems to be fading too quickly, use a stain with more pigment.
If you want to show off a distinctive grain, such as the knots in this rustic alder door, use a clear toner that brings out the rich colors and blocks UV. Ultra Premium Penofin Penetrating Oil in Transparent Chestnut, similar to shown; penofin.com
Even rot-resistant cedar tables and chairs can benefit from a stain to repel water. Spraying on the finish makes it easier to coat hard-to-reach surfaces. Krylon Semi-Transparent Wood Stain; krylon.com
Clear toner is great for new, high-end redwood or cedar decking, but on weatherbeaten or inexpensive decking, like this pressure-treated pine, semitransparent stain is the ticket to an upscale look. Flood TWF-Semi in Dusty Trail; flood.com
Most any stain made for decking can also be used on siding. Plus, it'll last longer than the same finish on a deck because vertical surfaces take less of a beating. On clapboards, Arborcoat solid-color stain in Barn Red; benjaminmoore.com
Semitransparent stains emphasize a fence's design, while clear toners show off its wood grain. Apply either type with a pump sprayer, the ideal tool for coating the long runs and numerous nooks and crannies of a fence. Wolman DuraStain Semi-Transparent in Chestnut Brown, similar to shown; wolman.com