Massachusetts Construction Supervisor License (CSL) Practice Test

What material is often recommended for underlayment in roofing?

1. Wood fiber

2. Felt paper

3. Plastic sheeting

4. Cardboard

The correct answer is: Felt paper

Felt paper is commonly recommended for underlayment in roofing due to its durable properties and effectiveness in water resistance. It acts as a protective layer between the roofing materials and the roof deck, helping to prevent moisture infiltration, which can lead to significant damage over time. Felt paper can withstand temperature variations and provide a secondary barrier against leaks, enhancing the overall weatherproofing of the roof. Unlike wood fiber, which may not offer adequate moisture protection, or plastic sheeting, which can sometimes trap moisture and lead to other issues, felt paper is specifically designed for roofing applications. Cardboard, while it may be an inexpensive option, lacks the necessary durability and moisture resistance required for effective roofing underlayment. Using felt paper helps ensure that the roof is well-protected and contributes to its longevity.