And in the end, these differences in how you measure pitch and slope don’t affect the quantity of roofing materials you are ordering.Īs roofs have gotten more complex, the span measurement is less useful because roof calculations needs to take into account different roof sections. You may notice then that what we’ve been referring to as “pitch” throughout this article is technically “slope.” While this can be confusing, pitch is the more common term that you’ll encounter.
While both measurements can be used to calculate roofing materials and determine roof type, they are different calculations.
Roof pitch is a measure of how much a roof rises in relation to its span. In other words, roof slope is the angle of a roof’s surface relative to the horizontal plane. What you’ll often see referred to as pitch is technically the slope.
Here’s the difference: slope is measured as the rise over run, while pitch actually refers to the rise over span (where span is the entire horizontal measurement of the roof, and therefore equals twice the run). You’ll often find the terms “pitch” and “slope” used interchangeably in the roofing industry however, there is a distinction as they refer to two different measurements.