North Carolina Building Contractor License Practice Exam

What is the designated minimum slope for a built-up roof?

1. 1:12

2. 1:20 (5% slope)

3. 1:30

4. 1:16

The correct answer is: 1:20 (5% slope)

The designated minimum slope for a built-up roof is 1:20, which equates to a 5% slope. This slope is required to ensure proper drainage of water away from the roof surface. Without adequate slope, water can pool on the roof, leading to potential leaks, structural damage, and decreased lifespan of roofing materials. The 1:20 slope provides a balance between effective drainage and practical construction considerations, making it a standard in the industry. A steeper slope can be beneficial, but the minimum of 1:20 is generally sufficient for ensuring that water is directed off the roof effectively.