Q: My husband wants to use a pressure washer to clean our deck because he thinks it will save time. I want to use a green cleaner that is non-toxic and environmentally safe. What is the proper way to clean a deck and keep it looking nice?
A: Pressure washers come in different sizes, and the end of the spray wand can be equipped with a variety of tips that concentrate the high-pressure stream of water in different ways. That stream of water cleans by agitating the surface of whatever it strikes.
Yes, a pressure washer can clean a wood deck much faster than you can scrub it by hand. However, a pressure washer may destroy the surface of the wood. The stream of water can be powerful enough to erode the light-colored spring wood fibers.
Professional deck cleaners argue with me that this happens only when an inexperienced user is working with the tool, the pressure was too great, the wrong tip was used, and/or the tip was held too closely to the wood surface.
If you decide to use a pressure washer, you should test it or have the professional you hire prove to you that he or she can use the tool without damaging the wood.
If you're really interested in making your deck-cleaning project a green activity, you should consider the secondary effects that gas- or electric-powered machines have on our environment.
I am a big proponent of non-toxic cleaners. Years ago I discovered that there are different types of bleaches, one of them being oxygen bleach. Many people think bleach is bleach, but the bleach found in most homes is chlorine bleach. The active ingredient in chlorine bleach is sodium hypochlorite. Check the label of many bleaches or deck cleaners and you might see this chemical name.
Oxygen bleach is a powerful cleaner that is just about as green as you can be. It is commonly available as a powder. The chemical makeup of the purest oxygen bleach is hydrogen peroxide and soda ash. When you mix oxygen bleach with water to make a deck-cleaning solution, all you create is more water, oxygen and soda ash.
The oxygen bubbles in the solution do most of the work done by the pressure washer. The solution soaks into the dry wood, and the oxygen ions deep-clean the wood by breaking apart dirt, algae and mildew molecules. The solution is not toxic to you or the plants.
There are many oxygen-bleach products available. You see them on infomercials, in warehouse stores, in grocery stores and on the Web. There is a difference in quality. The less expensive oxygen-bleach products often contain less of the active ingredient, and they might use an active ingredient that contains impurities or inorganic chemicals.
The purest oxygen bleach is made from raw materials that are food-grade organic chemicals. You can't get any greener or purer than that. (Full disclosure: I own a small business that sells oxygen bleach.)
The downside of using a green cleaner is time and elbow grease. You will have to do some additional mechanical agitation using a scrub brush on a long handle to get your deck squeaky clean. However, the wood will not be fuzzy, and there will be hardly any erosion of the soft spring wood.
My advice is to use oxygen bleach to clean the deck and have your husband help you with the scrub brush. If he must use his pressure washer, have him insert the 35-degree tip and use the machine only to do the final rinse. But if I were your helper, I would simply use a garden hose with a regular nozzle.
Tim Carter is a licensed contractor. To view previous columns or tap into his archive of information and sources of building materials, go to Ask the Builder at www. askthebuilder.com. Write to Tim Carter at P.O. Box 36352, Cincinnati, OH 45236-0352.