Chlorine bleach can destroy wood decks. Luckily, there’s another way to clean. (Tim Carter)

I had a dinner 22 years ago with a physical chemist. Ten days earlier, I had started to do research for my first column about deck cleaning. Before I share what happened at the dinner, allow me to tell you what I knew before meeting the chemist.

In the mid-1990s, all the information out there said to use chlorine bleach to clean decks and patios. I intuitively knew this was not the best practice because of what my next-door neighbor did each spring.

She always poured three or four gallons of pure chlorine bleach onto her concrete patio steppingstones, which were under a majestic maple tree. She spread it around with a push broom to clean the patio, and the bleach seeped down into the soil. The fumes were so powerful they made me sick. I warned her that the chlorine was so toxic it would kill the tree. She frowned at me and told me to mind my own business.

Each year, more and more of the tree died. After my neighbor had spent thousands of dollars on root treatments and injections, a company finally came and cut down the poor tree.

Let’s get back to the dinner conversation with the chemist. Before driving to the meeting to consume tender barbecued ribs, my research had uncovered these additional detrimental effects of using chlorine bleach outdoors on anything you own:

  • It destroys the lignin fibers that hold wood together.
  • It removes the natural color of the wood.
  • It’s highly corrosive to metal fasteners and framing connectors on wood decks.
  • It will poison ponds and lakes.

At dinner, the chemist introduced me to oxygen bleach. I thought chlorine bleach was the only bleach out there. I was wrong.

It turns out oxygen bleach had been around for decades. This product is a powder that’s mixed with water. Once you mix it, it releases trillions of invisible nontoxic pure oxygen ions into the solution. These ions are powerful cleaners and blast apart organic stains, mold, mildew, algae, sun-damaged deck sealers, cooking grease, etc. It’s safe to use on docks, as the solution that drips into the water adds needed oxygen to the lake or pond.

The best part is the oxygen bleach doesn’t harm any vegetation or trees. It doesn’t remove the color from anything. It doesn’t harm the lignin in natural wood. Oxygen bleach is completely safe for all composite decking, vinyl siding, fiber cement siding and outdoor furniture of all types.

The more the chemist told me about this magical product, the more intrigued I became. It turns out it was developed for the hospitality and hospital industries. Hotels, motels and hospitals were tired of spending vast amounts of money replacing bedding ruined by washing it with chlorine bleach. Oxygen bleach was color and fabric-safe.

In the late 1980s, an enterprising entrepreneur found out about oxygen bleach and introduced it to consumers. He started selling it as a carpet cleaner at small home and garden shows. Soon, he was advertising his brand on TV.

Now there are a number of oxygen bleach brands. Some are certified organic and some are not. It’s probably a good idea to use a certified organic one if you want to ensure you don’t damage any of your expensive outdoor possessions. The certified organic brands also are safe to use around all vegetation.

I’ve created a free downloadable document for you at my website. This document contains a list of all oxygen bleaches of which I’m aware. It also has links to videos, one of them showing why you do NOT want to use a pressure washer to clean your wood deck or teak outdoor furniture. A pressure washer can ruin anything made from wood.

Just go to askthebuilder.com/B1242 to get the free PDF.

Tim Carter can call you on the phone to solve your problem. Go to his website and fill out the form on this page: askthebuilder.com/ask-tim/.