It is that time of the year when our thoughts turn first to going out onto the deck or porch to enjoy the sun, and second to how ratty it has gotten since last year. Time to clean the deck, restore its color, kill the mildew, and recoat, not necessarily in that order. Here are a few guidelines that should help.
To kill mildew and algae: The traditional way is to mix one part common household laundry bleach 
with two parts water and wash down the deck. I use a swab mop on the flats and a pump type portable garden sprayer for the rails and posts. When it is dry, hose off the deck with plenty of water. Unfortunately, this will kill off any vegetation underneath. If you need a safer alternative, try Zinsser’s Jomax concentrated cleaner and mildew killer. It works great and won’t destroy plants. One gallon makes 20 gallons of solution, and oddly enough, is cheaper than bleach!
To restore gray wood to its original color: Mix oxalic acid (often sold as deck brightener) to about a 5% solution in water and flood it liberally onto the gray, raw wood. It will kill the gray and bring back the original color. Once again, wash off liberally with the hose when it is dry.
For just plain dirt: A good scrub with TSP or TSP substitute in water will help dislodge the dirt. Use a stiff bristle scrub brush to get things moving. As before, wash off afterwards with the hose.
When it is time to recoat: Let the deck dry and pick out the sealer you want. They fall into three categories. The weakest clear coating is waterproofing, which will offer rain shedding but very little protection and must be recoated often. Next come the clear sealers, that offer more protection, including UV block, and will last up to two years before recoating is needed. Finally, there are the pigmented opaque and semi-transparent sealer/stains. These offer the most protection, but block the true color of the wood. This year, I am putting Zinsser’s F&P clear deck coating on my deck and applying it with a wide format floor finish application pad. It is quick, easy, and adds just the right amount of finish in one 18″ wide swath.
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Where is the 18″-inch application pad available? All I see at Home Depot are pads around 8 inches wide.
Al Hicks
May 17th, 2009
They appear to be mostly a seasonal item. In my area they sell them at Lowes and Home Depot, but only during the summer when people are likely to do their decks. Typically they show up on an end cap display somewhere near deck coatings, but not in with the other permanent display of paint pads and rollers. Often they are sold as a kit with an extra wide paint pan to accommodate them.
You can also find them at outlets that sell to professional floor painters, but those tend to be better quality and higher price.
Last year I gave up and made my own by attaching two 8 inch pads together. It worked moderately well.
Of course, you can just use an 8 inch pad. It will go a bit slower, but it is easier to control. Unless your deck is very large (mine is about 750 square feet), a small pad is adequate.
admin
May 20th, 2009