Where preservative-treated wood is used in enclosed locations, what is the required moisture content?

• A. 16 percent or less
• B. 18 percent or less
• C. 19 percent or less
• D. 20 percent or less

Answer: (C)

The requirement for moisture content in preservative-treated wood used in enclosed locations is set to help prevent the risk of decay and insect damage. In this context, maintaining the regulation of moisture is crucial because higher moisture content can encourage biological growth, notably mold and rot, which diminishes the durability and structural integrity of the wood.

A moisture content of 19 percent or less ensures that the treated wood maintains an appropriate level of dryness for optimal performance. This threshold was established to balance the need for wood to find equilibrium in enclosed environments while maximizing the efficacy of the preservative treatment. Preservatives function best when wood is not saturated with moisture, which can lead to leaching and reduce the effectiveness of the treatment over time.

This level is commonly accepted in building codes and industry standards to promote longevity and reduce maintenance costs associated with wooden structures. Thus, the figure of 19 percent aligns with the established guidelines and practices for the responsible use of treated wood in various applications.