True or False: Tightly stacked materials can be damaged by moisture.

• A. False
• B. Moisture has no effect
• C. It depends on stack
• D. True

Answer: (D)

Moisture can cause damage to materials even when they’re tightly stacked because trapped humidity between layers slows drying and creates favorable conditions for deterioration. If a stack sits in a damp environment or experiences temperature changes, water can migrate between sheets. Tight packing restricts airflow, so that moisture doesn’t evaporate quickly and stays in contact with surfaces. In metal, that moisture accelerates rust and corrosion, especially at edges or where coatings are compromised. In wood or composites, moisture causes swelling, warping, and weakened bonds. Mold or rot can also develop when moisture is held between layers. So the possibility of damage remains even with a tight stack, making the statement true.