North Carolina Building Contractor License Practice Exam

How many inches should roof deck typically endlap over supports?

1. 50 inches

2. 75 inches

3. 100 inches

4. 125 inches

The correct answer is: 75 inches

The typical endlap for a roof deck over supports is generally recommended to be 75 inches. This distance is important because it helps ensure structural integrity and weather-tightness of the roof assembly. By providing a sufficient overlap, you can enhance the performance of the roofing system against elements such as wind uplift, rain penetration, and thermal expansion/contraction. A 75-inch endlap allows for adequate fastening and ensures that the weight and loads imposed on the roof deck are evenly distributed across the underlying supports. This practice also complies with common building codes and manufacturer specifications, which are designed to protect the structure from potential damage and maintain its longevity. While other measurements, such as 50, 100, or 125 inches, may exist in different contexts or materials, they do not align with the standard requirements for roof deck endlapping practices in most typical construction scenarios as defined by industry guidelines.