As winter’s harsh weather fades and we start looking forward to enjoying the outdoors again, one thing that’s sure to be on everyone’s to-do list is sprucing up those exterior decks. This is the ideal time to take a look at how your deck made it through the winter, and to do a little cleaning and maintenance to get things ready for an enjoyable summer season.
The first job is an inspection. If you haven’t already done so as part of your annual spring checklist, you need to take the time to really give your deck a thorough checkup. Look for loose or missing screws and nails. Tighten loose nuts and bolts in railings and stairs.
Examine the condition of all the wood, looking for cracks, splinters, dry rot and other signs of structural problems. If you discover anything of concern, those things need to be dealt with prior to doing any cleaning work.
Start with a general cleaning, to get rid of the obvious stuff. The safest and easiest thing to do at this point is just a good sweeping. Remove leaves, pine needles, dirt, and other loose debris that can get ground into the wood.
Next, you want to remove all of the gunk that gets wedged in between the boards. Dirt and other debris between the boards prevent drainage, encourage mildew and rot, and can lead to premature failure of the boards.
Use a simple tool such as a plastic putty knife to push the debris through, or scrape it up. Do another sweeping to remove anything you’ve brought up onto the deck.
At this point, you can wash the deck. Here’s where a bit of controversy comes in. A lot of people like to use a pressure washer for this task, because it gets the work done quickly with a minimal amount of labor. However, done incorrectly, it can also do a lot of damage by breaking apart the cells and fibers in the wood, leaving the wood with a rough and fuzzy appearance.
If you want to use a pressure washer, make sure to use low pressure and a wide fan-type nozzle so as not to concentrate the pressure into a damaging stream. For deck cleaning, an equally effective method is to use a garden hose with a wide spray nozzle combined with a medium bristle push broom or a nylon scrub brush on a long handle.
Another thing you don’t want to do to your nice wood deck is break out that bottle of regular household bleach. Chlorine bleach, of the type used in the laundry room, isn’t going to help you get the dirt off your deck. But what it will do is bleach out some of the wood’s natural coloring, taking the attractive original browns and yellows in the wood and turning them to unnatural whites and grays.
Another side effect of regular chlorine bleach is that it breaks down the fibers in the wood, similar to the effects of excessive pressure washing. Here again, that can create the same type of fuzzy appearance in the wood. It also defeats the whole purpose of doing the cleaning, because it opens the wood fibers up for more dirt and water to enter.
Fortunately, you have other options. Several companies now make non-chlorine bleach products that are specifically formulated for cleaning wood decks. These products are safe and easy to use, and do an excellent job of cleaning decks without damaging them.
These deck-cleaning compounds contain what is typically known as "oxygen-based bleach." They’re a dry powder containing a material called sodium percarbonate, which is also found in many color-safe laundry bleaches. When dissolved in water, it releases safe hydrogen peroxide and soda ash. Oxygen-based deck cleaning solutions, properly applied, can be very effective at getting rid of your deck’s gray, weathered discoloration, as well as dirt and mildew.
If you have a deck made from cedar, redwood or certain other materials, you may be dealing with problems caused by a natural resin in the wood called tannin. Tannins are reddish-brown in color and can work their way to the surface of the wood, leaving discolorations. They can also react with certain metals in deck fasteners and other hardware. For that problem, try an oxalic acid-based cleaner after you’ve done your other cleaning.
Take the proper precautions
Most of these products are very safe to use, both for yourself and for the environment. But that doesn’t mean you should take them lightly!
When you buy your products, be sure that you get an MSDS (Material Safety Data Sheet) from the retailer. Carefully read and follow all of the precautions on the MSDS and the manufacturer’s product label for ventilation, protective clothing and equipment, proper application procedures, protection for surrounding surfaces, and other safety issues.
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