Explanation of Roof Pitch

Definition

• The pitch of a roof is essentially its angle downward, commonly called its slope. The higher the pitch, the steeper it is. Pitch is measured in inches. Roofs with a pitch of at least 3.215 are considered to be pitched.

Purpose

• Roofs are created at a pitch for a reason. They can redirect rain and snow downward, rather than allowing it to accumulate on top of a building, where it can place excessive pressure on the roof to the point of caving it in. Thus, homes in parts of the world that get a lot of rain and snow tend to have higher pitches, allowing the rain or snow to run down to the ground easier.

Finding Pitch

• The pitch of an existing roof can be measured in various ways. The first requires no special tools, aside from a tape measure and perhaps a calculator if you’re not good at math. Using this method, you can find the pitch by plugging in your roof’s numbers to the following equation: pitch = (rise /run)12 (the 12 represents the number of inches in a foot.) If you’re not mathematically inclined, you can use a pitch finder. Simply place the tool on top of your roof, or on a gable end soffit, or under a rafter in the attic, and the tool will tell you the pitch.

Pitch Rules

• Some parts of the country have building codes that set a minimum required pitch for buildings. These rules take into account the amount of rain and snowfall in those areas and are meant to ensure safety, so that roofs do not cave in easily to rain and snow in the amounts typical to those regions.