Slope and Pitch Problems on the Roofing Contractor's Test

Slope and pitch problems are typical in roofing exams. Let’s understand what they are and the difference between them.

Slope, in roofing, is expressed or the rise (in inches) per 12 inches of run. For example, in the diagram below, we have a slope of 6 in 12. Why? Because the rise every 12” is 6” of the run. In other words, it rises half as fast as it runs.

Pitch, in roofing, is expressed or the total rise over the total span the pitch of this roof is 12’ rise / 36’ span or 1/3.

Note: We get 1/3 by dividing both 12 and 36 into 12.

How to convert from Pitch to Slope

• Multiply the Pitch times 2
• Multiply both numerator and denominator by the only number that allows the denominator (bottom number in a factor) to get to 12

For example: Convert a pitch of 1/4 to slope

• 1/4 x 2 = 1/2
• 1/2 x 6/6 = 6/12 => 6 in 12 is the slope equivalent to a pitch