1. What is Rise Over Run?

Rise over run is a fundamental concept in mathematics and construction that represents the slope or gradient of a surface. For roofs, it describes the vertical rise per unit of horizontal run, typically expressed as a ratio.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( \text{Rise} \) — Vertical height difference (inches)
• \( \text{Run} \) — Horizontal distance (inches)

Explanation: The pitch ratio indicates how many inches the roof rises for every inch of horizontal run. A ratio of 1:4 means the roof rises 1 inch for every 4 inches of horizontal distance.

3. Importance of Pitch Ratio Calculation

Details: Calculating roof pitch is essential for proper drainage, structural integrity, material selection, and building code compliance. Different roof pitches are suitable for different climates and architectural styles.

4. Using the Calculator

Tips: Enter both rise and run measurements in inches. Ensure measurements are accurate and taken from the same reference points. Both values must be greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical roof pitch ratio?
A: Common residential roof pitches range from 4:12 to 12:12, meaning 4 to 12 inches of rise per 12 inches of run.

Q2: How do I convert pitch ratio to degrees?
A: Use the formula: angle = arctan(rise/run). Most smartphones have calculator apps that can compute this.

Q3: Why is roof pitch important?
A: Pitch affects water drainage, snow load capacity, attic space, and suitable roofing materials.

Q4: Can I use different units for rise and run?
A: No, both measurements must use the same units for an accurate ratio calculation.

Q5: What's the minimum pitch for different roofing materials?
A: Asphalt shingles typically require at least 4:12 pitch, while metal roofing can work with pitches as low as 1:12.