How is the roof pitch typically expressed?

The roof pitch is typically expressed as a ratio of vertical rise to horizontal run because this method provides a clear and standardized way to communicate the steepness of a roof. In this format, the first number indicates the vertical rise (the height of the roof) and the second number indicates the horizontal run (the distance from the peak of the roof to the edge, or eave). For example, a pitch of 4:12 means that for every 12 inches of horizontal distance, the roof rises 4 inches.

This ratio is widely used in construction and architecture, as it helps builders and designers accurately understand and convey the dimensions and angles involved in roof design. It also facilitates calculations related to roofing materials, drainage, and structural support. While other methods of expressing roof pitch, such as percentages or degrees, exist, the ratio of vertical rise to horizontal run remains the most common and practical expression in the industry.