Can I Bleach My Wood Deck?

Matt Marandola
Written by Matt Marandola
Updated June 10, 2021
Large wood deck
© EricVega / E+ / Getty Images

Yes, you can bleach your wood deck—with a few important caveats

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You may have noticed your deck looks grimier than usual after a summer of muddy paws and footprints, and you’re looking into bleaching your wood deck. However, when you throw chlorine bleach on wood, you run the risk of ruining the wood. Plus, there’s a chance it will merely hide the dirt instead of washing it away. So instead, you’ll want to use oxygen bleach and follow a few critical steps to get your deck back to looking brand new.

Why Shouldn’t I Use Chlorine Bleach?

Chlorine bleach, which is probably your go-to for countertops, sinks, and tubs, seemingly works miracles by killing off bacteria and mildew and eliminating stains. 

But sometimes, bleach’s cleaning power can be too much of a good thing when it comes to wood. Wood has cells that hold the fibers together, known as lignin. Chlorine bleach is so strong that it can destroy your deck’s sealant and then seep into the wood underneath. Once it hits the wood, it will start to destroy the lignins.

Chlorine bleach will undoubtedly lighten the wood—so much so that you might notice it continues to lighten over several months. What once was a lovely light brown wood will start to look like you stained your deck white. This is because the lignins eventually break down and the bleach stains every single fiber, rather than only the surface.

This doesn’t even really clean the wood, but more so lightens the deck. So dirt and grime only hide behind a mask rather than getting escorted off the deck.

Environmental Safety

Not only does chlorine bleach negatively impact your wood deck, but it can take a toll on the surrounding lawn and landscape. After a hit of bleach, those beautiful boxwoods you worked so hard to grow will start to wither and die. Ouch.

Running chlorine bleach off into the drainage system doesn’t help either—you’re simply diverting it from your plants into waterways where wildlife live and drink.

The Solution: Use Oxygen Bleach on Your Wood Deck

Oxygen bleach provides many of the same benefits as chlorine bleach but without the risk of ruining the deck and anything else around it. Rather than having a chlorine base, it uses a hydrogen peroxide base. It mainly focuses on killing off fungi and bacteria, rather than everything like chlorine bleach.

What Is an Alternative to Bleaching Your Wood Deck?

Rather than using oxygen bleach, you can simply opt for the main ingredient, hydrogen peroxide. It performs just as well in the department of cleaning and sanitizing, but saves on the extra sodium found in bleach.

Hydrogen peroxide oxidizes one of the oxygen molecules, which means you’re only leftover with water afterward. Sorry for the high school chemistry throwback, but basically, it means that it’s safer for plants and animals.

Patio with wood deck
© EricVega / E+ / Getty Images

How Often Should You Clean Your Deck?

Ideally, you’ll want to clean your deck every few months without bleach. This can be a simple hose down with a higher water pressure than usual. Unless the dirt is really bad, you shouldn’t even need a pressure washer.

Try to only use bleach on your deck every two to three years to help preserve the seal. When you do use bleach, you’ll want to reseal your deck afterward.

There a few tips you can use to help keep your deck clean throughout the year. These tips include sweeping often and ensuring the deck has a seal.

Seal your deck every two to three years, as this is your primary defense against the forces of nature. Even if it hasn’t been that long and you find the seal over your deck is gone, always reseal it as soon as possible. Without it, termites, fungi, and liquids have a chance of destroying your deck.

Hiring a deck cleaning near you can prove one of the best ways to maintain your deck. They’ll ensure the dirt disappears and the sealant stays.

What Do You Do After You’ve Cleaned Your Deck?

Once the deck is clean, you’ll want to use oxalic or citralic acid, which you can pick up from your local hardware store, to help bring down the pH of the wood to a neutral level. This keeps the lightened color without destroying the lignins inside the wood.

After you’ve applied the pH balancer and it has sat on the wood per the label’s instructions, you can start the process of staining or painting your wood deck again. Cleaning a painted deck has a slightly different process which includes using very mild cleaners and avoiding using any type of high water pressure.

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