Caring for Outdoor Wood Furniture
DEAR TIM: My outdoor wood furniture has weathered to a mottled gray and there is mildew covering it. My wife has informed me that I must make it look like new. If I do a good enough job, I've been told I can then refinish the kid's playset. What's the best way to get the wood looking like new? How should I clean it? What's the best sealer to use? If you were doing this job, what secret tips can you offer to get the best results in the shortest amount of time? Steve P., Mannassas, VA
DEAR STEVE: It's just as important to keep your better half happy as it is to clean and protect outdoor wood furniture. I urge you to maintain a positive attitude through this entire project. I've been married nearly 38 years to the same wonderful woman and have discovered that keeping her happy completing projects is some of the glue that holds marriages together.
Cleaning and sealing any outdoor wood is not much different than doing the same thing for a wood deck. Outdoor wood tables, chairs, fencing, wood playsets, arbors, etc. all take the same abuse from Mother Nature.
If you fail to maintain outdoor wood it will eventually rot and crack to pieces. Chemically treated lumber is able to resist rot for decades. Some wood like redwood, cedar, teak and other hardwoods contain varying degrees of natural wood preservatives. But water that soaks into all these wood species will cause them to crack.
The cracks start out as tiny checking cracks. Water entering the wood causes it to expand. As it dries, it contracts. This movement creates the tiny cracks. If water gets into the cracks, it soaks deeper into the wood causing even greater expansion and contraction forces that cause the cracks to get deeper and wider.
You can see why it's important to treat all wood with a water repellent on a regular basis to prevent water from getting into the wood. Do this every other year or so and your outdoor furniture and playset will look fantastic instead of resembling a 50-year-old fishing pier.
I prefer to clean outdoor wood with oxygen bleach. Do not use oxygen bleach on redwood as it can darken this wood species. Use oxalic acid to clean redwood.
Do not use a pressure washer to clean outdoor wood. It absolutely will damage the wood. The high-pressure stream of water erodes the softer lighter colored bands of spring wood that are found between the darker bands of summer wood grain.
Allow the wood to dry well after it's clean. The washing process almost always raises the grain of the wood. This means you'll have to sand it to get it back to that smooth furniture finish. Don't skip this important step. A palm sander works great for this project. Use a medium aluminum oxide sandpaper. This paper self sharpens itself as it's being used.
Once the wood is sanded, you should seal it with a pigmented synthetic resin water repellent. Do not use an oil-based product. Most oil-based sealers are food for mildew and algae. The manufacturers place mildewcides and algecides in the products to slow down the growth, but water and sun break down these chemicals. The pigmented, or colored sealers, will keep the furniture looking spectacular. Clear sealers will gray rapidly.
I urge you to work in the shade when applying the sealers. Some sealers require you to apply two coats within 15 minutes of each other to get maximum protection. Working in direct sunlight can shorten this time dramatically leading to ugly spotting and overlaps.
Working in the shade is easier on you, the wood and the sealer. If you can move the furniture inside your garage or other covered work area, do so. I realize this is impossible for the playset, so choose to work on an overcast day if possible.
Staining and sealing outdoor furniture is quite different than sealing a deck. It requires a fine touch so your brush strokes are not seen and you don't create any overlap marks.
You have to maintain a wet edge with the sealer which means that you stain each piece of wood completely so that you don't stop working until you reach the end of that piece of wood or it intersects with another piece of wood. Failure to do this can result in very unattractive overlaps where the color of the sealer seems darker at the overlap area.
You can watch an informative video showing how to apply outdoor wood sealers. Just type ""deck stain video" into the www.AsktheBuilder.com search engine.