What best defines condensation in roofing terms?

• A. The change of water from vapor to liquid when warm, moisture-laden air comes in contact with a cold surface.
• B. The method of sealing joints with tar.
• C. The process of applying roofing cement.
• D. The color of shingles.

Answer: (A)

Condensation in roofing terms is the change of water from vapor to liquid when warm, moisture-laden air contacts a cold surface. In a roof assembly, warm indoor air can migrate into the attic or under the roof deck and meet cooler materials, causing the water vapor to condense into liquid water. This moisture can dampen insulation, lead to wood rot or mold, and affect overall roof performance. Understanding this helps explain why proper ventilation and vapor barriers are important to control moisture movement.

The other options describe sealing with tar, applying roofing cement, or the color of shingles, none of which involve the phase change of water vapor into liquid on cool surfaces.