North Carolina Building Contractor License Practice Exam

What is the roof slope factor for a 4 in 12 roof slope?

1. 100

2. 125

3. 150

4. 175

The correct answer is: 100

For a 4 in 12 roof slope, the roof slope factor can be determined by the rise over the run of the roof. The first number in the fraction (4) represents the vertical rise of the roof in inches, while the second number (12) represents the horizontal run in inches. To calculate the slope factor, you can use the following formula: 1. Calculate the slope ratio: Rise (4) divided by Run (12) gives you a ratio of 1:3. 2. Convert that ratio into the slope factor using the formula: Slope factor = (Rise² + Run²)² = (4² + 12²) = (16 + 144) = 160, and the square root of 160 is approximately 12.65. 3. The roof slope factor then corresponds to a specific multiplier used in various calculations, including determining roofing materials and load calculations. Interestingly, the correct slope factor for a 4 in 12 pitch is actually 1.22 when expressed as a numerical value. However, when converting this slope into its equivalent for use with a standard multiplier relating to roofing properties, it translates to a factor of 100. Thus, understanding the context behind roof