Excessive moisture can destroy the effectiveness of which building component?

• A. Insulation
• B. Paint
• C. Roofing
• D. Windows

Answer: (A)

Excessive moisture undermines insulation by destroying the air-filled spaces it relies on to resist heat flow. The core of most insulation is to trap air, which is a poor conductor, so dry insulation slows heat transfer effectively. When it gets wet, water fills those air gaps and increases the material’s ability to conduct heat, causing the R-value to drop. Wet insulation can also sag, compress, or lose loft (especially fiberglass), further reducing its effectiveness. Moisture also promotes mold and decay, which can diminish performance over time. While moisture can affect paints, roofing, or windows, the direct, most impactful effect is on insulation’s ability to insulate.