C
Calcuable

Roof Pitch

Calculate pitch in percentage and degrees.

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m

Explanation

Roof pitch is crucial for choosing roofing materials (shingles, tiles, metal) and water drainage. It is expressed in degrees (°) or as a ratio (rise/run). ### Ratio vs Degrees - **Ratio (US)**: Rise over Run (e.g., 4:12 means 4 inches rise for 12 inches run). - **Degrees**: The angle relative to the horizontal. - **Percentage**: (Rise / Run) x 100. ### Common Pitches - **Flat Roof**: < 2:12. - **Low Pitch**: 2:12 to 4:12. - **Conventional**: 4:12 to 9:12. - **Steep**: > 9:12. ### Formula Pitch = Rise / Run. Angle = arctan(Rise / Run).

Examples

  • Rise of 4ft over a run of 12ft = 4:12 pitch. Angle ≈ 18.4°.
  • 12:12 pitch (45°) rises 12 inches for every 12 inches of run.

FAQ

Minimum pitch for shingles?

Usually 2:12 is the absolute minimum, but 4:12 is standard for safety and drainage.

How to measure safely?

Measure the rise and run in the attic, or use a pitch gauge app on your phone from the ground.

Disclaimer

Always verify calculations with an architect or engineer before starting work.