Which lumber should be avoided in construction due to moisture content?

Which lumber should be avoided in construction due to moisture content?

• A. Kiln-dried
• B. Dry
• C. Green
• D. Air-dried

Answer: (C)

Moisture content controls how stable wood is after it’s installed. Wood with high moisture content swells when it’s fresh, then shrinks as it dries, which can cause gaps, warping, twisting, or nails and joints loosening over time. Green lumber is freshly cut and has a high moisture content, so it’s the least predictable and most prone to movement in a construction setting. In contrast, lumber that’s kiln-dried, air-dried, or simply described as dry has lower, more stable moisture levels, making it hold its size better, accept fasteners and finishes reliably, and perform consistently under load. That’s why green lumber is avoided for most structural work.

Moisture content controls how stable wood is after it’s installed. Wood with high moisture content swells when it’s fresh, then shrinks as it dries, which can cause gaps, warping, twisting, or nails and joints loosening over time. Green lumber is freshly cut and has a high moisture content, so it’s the least predictable and most prone to movement in a construction setting.

In contrast, lumber that’s kiln-dried, air-dried, or simply described as dry has lower, more stable moisture levels, making it hold its size better, accept fasteners and finishes reliably, and perform consistently under load. That’s why green lumber is avoided for most structural work.