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Chemicals used in treated wood can be harmful to humans. That's why it's important to follow safety precautions, such as wearing gloves, avoiding inhaling the sawdust, and not burning treated wood.
Photo credit: Glowimages/Getty ImagesWood is an excellent building material—strong, lightweight, easy to work with, and relatively affordable. However, the downside is that many types of bacteria, fungi, and insects are attracted to it. When wood comes into contact with soil or moisture over time, these organisms begin to damage it. Untreated woods, like pine, may only last one or two years when in contact with damp ground.
Pressure-treated wood is timber that has been saturated with a liquid preservative inside a pressure chamber. The pressurization forces the preservative deep into the wood fibers, ensuring it reaches the core, making this method much more effective than simply soaking the wood.
The most commonly used chemical for treating wood was chromated copper arsenate (CCA). However, in 2003, the Environmental Protection Agency limited its use in residential areas due to concerns about arsenic leaching from the wood. A popular substitute for CCA is alkaline copper quat (ACQ), which is effective in preventing decay caused by insects and fungi. ACQ bonds strongly with wood fibers, allowing the wood to endure for decades even in contact with the ground.
The level of protection offered by the chemical treatment depends on how much of the chemical the wood absorbs. In the U.S., the quantity of chemical is measured in pounds per cubic foot of wood. For ground contact, 0.40 pounds per cubic foot is required, and for foundation use, 0.60 pounds per cubic foot is standard.
The chemicals in treated wood can be harmful to humans. That's why safety precautions, such as wearing gloves, avoiding inhaling sawdust, and not burning treated wood, are recommended. It's also advisable to keep small children away from treated wood.
