How to Prepare the Deck for the Long Winter
If, after sweeping, your deck looks nice and clean, that’s good. More often, however, (given the state of our nation’s air) that deck is going to need a good scrubbing with one kind a cleaner.
If things look really bad, with stained areas that give the deck a blotchy look, you’ll want to do your cleaning with a fairly powerful cleaner. Most hardware stores and lumberyards sell powdered cleaners made especially for decks. They’ll not only get rid of dirt, but they’ll also bleach out those dark blotchy areas, restoring the deck to a reasonably uniform appearance.
These cleaners are easy enough to use. Just mix them with water as directed on the label, apply to your deck and scrub in well. Let it set for about 15 minutes, then hose it off.
If some areas didn’t lighten as much as you’d hoped, you can go back over them using a stronger concentration of the same cleaner. That should do the job.
If your deck is uniform in color, but simply dirty, you can mix your own cleaner. A quarter of a cup of dishwasher detergent in a gallon of hot water works well. Make sure the water is very hot or the detergent may not dissolve properly.
Because much of the ”dirt” you find on decks is really mildew, it pays to add a cup of chlorine bleach to your mix. This will kill and remove the mildew like magic.
Use this mix just as you would a commercial cleaner. Swab it on, scrub it in, let it set and then hose it off.
Once your deck is clean, let it dry for a couple of days. Then think about protecting it. The combined effects of wind and rain, freezing and thawing, wetting and drying are hard on any wood.
The problem is even more severe on horizontal surfaces like decks. So some kind of sealer makes sense, even on pressure-treated wood. Remember, pressure treatment protects only against rot and insect damage, not the ravages of the weather.
What kind of sealer is best? If your deck has never been finished, you might consider using an exterior stain. Stains provide good protection and let you make your deck the color you like (hiding the sickly green color of treated lumber, for example). They can also even out the color of your deck, if it has weathered in patches.
The easiest way to apply stain is with a paint roller and extension handle. Roll the stain onto an area about four feet square, then go over that area with a tool like the one shown in the sketch. You can make this tool by gluing or stapling a scrap of carpet to a scrap of wood and screwing on a handle about four or five feet long.
A similar tool, made by gluing carpet to a scrap of sheet metal and mounting this vertically on another long handle is good for getting the stain into the cracks between deck boards. These homemade tools help work the stain deep into the wood for best coverage and protection.
Make sure you pick a stain made for use on decks. These are generally semi-transparent. Opaque stains aren’t recommended because they tend to chalk and wear off on your shoes and clothes. If in doubt, read the label. This will generally tell you whether the stain is good for use on decks.
If you are happy with the color of your deck as it is, a clear sealer is in order. These are made by a variety of makers, with and without wood preservative.
If your deck is pressure-treated, there’s no point in fooling around with preservatives. A clear sealer, like Hope’s Exterior Tung Oil or Thompson’s Water Seal, will do fine. If your deck isn’t pressure-treated, and especially if it isn’t made of a decay-resistant species like redwood or cedar, a preservative sealer is definitely a good idea.
Whatever you use, apply it according to label directions. The roller and pads described above will help speed the job along.
Note: These clear sealers work well, but they don’t last forever. In fact, most have a relatively short lifespan. A year, or maybe two at the most, is all you should expect from them.
When water stops beading up on your deck, you know the sealer is losing its effectiveness. Then it’s time to put on another coat.
