Construction Supervisor License Practice Exam

When installing a new roof over wood shingles, the old roof must be what before installing the new roof?

1. Covered with gypsum board, mineral fiber, or other approved material

2. Treated with a fire retardant

3. Sealed with an approved waterproofing agent

4. Furred out with 1" x 2" or 1" x 3" strips

The correct answer is: Covered with gypsum board, mineral fiber, or other approved material

In the context of installing a new roof over wood shingles, the requirement for covering the old roof with gypsum board, mineral fiber, or other approved material is crucial primarily for fire safety and moisture control. Wood shingles are combustible and can pose an increased fire hazard if not appropriately managed. The covering acts as a fire barrier, providing an additional layer of protection that helps prevent the spread of fire. Moreover, using materials like gypsum board can also support the structural integrity of the new roof installation by creating a stable and smooth surface. This helps ensure that the new roofing material adheres properly and performs as intended. In addition to fire safety, this approach can also assist in reducing moisture infiltration, which is key in preventing mildew and rot—issues that are particularly pertinent with wood underlayment. By addressing both fire resistance and moisture control, this method enhances the longevity and safety of the roofing system as a whole.