Why Pressure Treated Decks don’t hold up


Actually, we are. Many folks mistakenly believe that just because their deck is made from pressure treated lumber that it will last forever. All that chemical is supposed to stop aging from the sun and fungus and bugs indefinately, right? Not really. It slows it down for sure. But stop it? Nope.

Sunlight contains ultraviolet radiation (UV) that turns wood gray and “cooks” it if you will. UV damage is severe. What would your face look like if it were exposed to sunlight during the summer months hour after hour, day after day?

Oh, it is? Well, that’s why you look the way you do then.

Another huge reason is the natural process of water being absorbed into the wood from rain and snow and condensation and then evaporating out again simultaneously as the temperature goes up and down. This makes your deck or dock wood expand and contract over and over again which produces something called “checking” which means the wood cracks which in turn produce splinters.

But then something really bad happens: Pollen and dirt and leaves and dirt fall into the cracks. It is nice and damp in those cracks so mold, mildew and fungi begin to eat the delicious meal of organic material down in the 1000s of cracks in your deck. That’s why your decking soon looks green or black:Fungus among us. Fungi and bacteria are the main decomposers of organic matter in virtually all ecosystems on Earth. Fungi release digestive enzymes that decompose things around them, turning them into food. Guess what the fungi hiding in your cracks eat when they run out of pollen and leaves? Yup. Wood. They break down the wood cellulose and eat the wood sugars. Yum, yum.

As if this wasn’t enough, when water gets down into the 1000s of cracks on your deck and freezes, the ice expands and opens the cracks up so they become huge… and collect more pollen and leaves and dirt… which feeds more fungi that grow and grow and the cycle repeats.
The underside of a deck is also growing mold and fungus sometimes as ferociously as the top because the underside is moist and humid and hidden from the sun. Yes, your deck is rotting from the ground up.

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