Dirty Decks: Tips to Clean & Seal Them

Decks get really dirty so a common spring time ritual is cleaning your deck, porch, walkways, etc. In addition to a good annual cleaning, wood decks need to be sealed to protect them from the elements which otherwise, will cause them to deteriorate faster than they will with proper maintenance.

We're all busy, life happens and too often, common home maintenance chores get pushed aside and I'm s guilty as everyone else. That's why most home owners are now putting up decks and fences that require less maintenance, using composite deck materials that still need to be cleaned but won't rot due to excessive moisture.

For homeowners with a wood deck, porch or fence, this article explains the elements and how they damage your wood structures, and how to clean and seal them so they last as long as possible.

What Damages Wood Decks, Fencing, Siding and More

When you go out in the summer many people wear sunglasses, and most people put on sunblock at the beach. We realize the sun affects our skin and it does similar damage to your home when it's not protected. You can tell when your windows get dirty but it's harder to see the damage the elements are doing to the wood on your home, i.e. why wood homes are painted or stained.

• Sunlight – or the ultraviolet rays bleach wood fibers and break down their cell structure.
• Water – that gets absorbed into the wood washes out the natural resins and color. When the water freezes and thaws, it causes the wood to crack and splinter.

While sunlight damages the surface of the wood, water is a much bigger concern. When the moisture level approaches 20%, you have conditions for wood rot. Proper drainage is critical to make sure water doesn't pool on warped boards, doesn't get trapped by dirt between floor boards or around the perimeter of your deck, especially where it connects to the house. Wood rot is like cancer, growing unseen for a long time.

• Mold, mildew, algae and fungus – grow when they have wood and moisture, as wood is a natural food source. That's what causes the black, green and gray discoloration of your home's wood structures.
• Dirt and other contaminants – include food, air borne pollution, dirt and whatever else you track across your deck when walking. Some of these are also food sources for mold, etc.

Different Ways to Clean Your Wood Deck

Hopefully you now understand why you need to seal your deck (read …) but before you do that, you've got to get the deck nice and clean and there are several choices to pick from.

• Chlorine based bleach – is popular but controversial. It's a good cleaner, good mildewcide but use too much and you'll damage the wood fibers. Bleach breaks down the lignin, that holds wood fibers together so you need to dilute … so the most common formula is 3 quarts water, 1 quart household bleach and 1/4 cup of liquid dishwasher detergent (ammonia free) or TSP.
• Oxygen bleach (also called Sodium Percarbonate or Disodium Peroxydicarbonate) – is a detergent and bleaching agent based on hydrogen peroxide. It is a white, non-toxic  powder that is dissolved in water. A key feature is it's biodegradable, making it environmentally friendly. Do not use on new wood.
• Pressure washing – is also controversial because it's too easy to damage the wood if you don't know what you're doing. You need to use the lowest pressure possible and a larger nozzle will also lower the pressure but be sure to test on the underside of the deck, starting with low pressure and increasing as necessary.

After cleaning your deck, you may need to remove the fuzzies, which can happen with even low or no pressure washing. That's because the suns ultraviolet rays kill the outer layer of wood (what turns a deck gray) and this dead wood can be removed with a light sanding.

For more tips on maintaining your deck, read Sealing Your Deck to Protect the Wood and/or Water & Wood Rot Repairs: Decks.