Is that beautiful wood siding or deck looking a little tired and blah? It doesn’t have to.
Let’s look at what causes discolored wood, and give you some ideas on what you can do.
First guess? Yep, dirt. Try scrubbing with a stiff brush and a detergent solution. If it comes off, that’s all you need to do.
Then there’s mildew. If the wood doesn’t get a lot of sun, and tends to dry out slowly after rain, you may see a green or black tinge on the wood. Plain-old household bleach will do the trick. Try pouring a little on an unobtrusive section, and rinse it off after a few minutes. If this does it, you can mix a solution of 1:3 bleach to water, and add 3 tbsp of trisodium phosphate (TSP)/gallon. Apply this with a sponge to the deck or with a sprayer to the siding. After a few minutes, rinse well.
Staining can come from a number of sources, including natural tannins in the wood or rusting nails. And weathering — caused by sun and rain — can make the wood look picturesque — or ugly, depending on your point of view. For both of these problems, use a tsp solution or “wood bleach” (oxalic acid), or look at various commercial solutions designed to “renew” your wood. Always read and follow instructions carefully.
Here are a few additional cautions when working with chemicals like these: wear rubber gloves, don’t mix bleach with cleaners like ammonia, and rinse everything, including your tools, with lots of water.