Illinois Roofing Practice Exam

Which one of the following statements is true?

1. Vapor moves from outside to inside a building in cold weather

2. Vapor has no effect on roofing materials

3. Vapor moves from inside toward the outside of a building in cold weather

4. Vapor is unaffected by temperature

The correct answer is: Vapor moves from inside toward the outside of a building in cold weather

The correct answer points out that vapor moves from inside toward the outside of a building in cold weather. This phenomenon occurs because inside environments are typically warmer and more humid than the outside during colder months. As a result, the moisture-laden air within the building seeks to escape to the drier, colder conditions outside. Understanding this movement is crucial for roofing professionals, as improper management of vapor barriers can lead to condensation problems within the roofing system, causing potential damage to materials over time. The other statements are not accurate. For instance, vapor does have significant effects on roofing materials—excess moisture can compromise the integrity of the roofing system. Additionally, the movement of vapor is indeed affected by temperature; warmer air can hold more moisture than colder air, influencing how vapor behaves in different conditions.