1. What is Roof Slope Angle?

The roof slope angle is the angle between the roof surface and the horizontal plane, typically expressed in degrees. It determines the steepness of a roof and affects drainage, material selection, and structural requirements.

2. How Does the Calculator Work?

The calculator uses the trigonometric formula:

Where:

• \( Rise \) — Vertical height (inches)
• \( Run \) — Horizontal distance (feet)
• \( \arctan \) — Inverse tangent function

Explanation: The calculator converts run from feet to inches, calculates the angle in radians using the arctangent function, then converts the result to degrees.

3. Importance of Roof Slope Calculation

Details: Accurate roof slope calculation is essential for proper water drainage, selecting appropriate roofing materials, meeting building codes, and ensuring structural integrity.

4. Using the Calculator

Tips: Enter rise in inches and run in feet. Both values must be positive numbers. The calculator automatically handles the unit conversion and trigonometric calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between slope ratio and angle?
A: Slope ratio (e.g., 4:12) represents rise over run, while angle represents the actual degree measurement of the roof's incline.

Q2: What are common roof slope angles?
A: Low slope: 0-10°, Conventional: 10-30°, Steep slope: 30°+, with specific angles varying by roofing material requirements.

Q3: How does roof slope affect material choice?
A: Different materials have minimum slope requirements - asphalt shingles typically need 2:12 (9.5°), while metal roofing can go as low as 1/4:12 (1.2°).

Q4: Why convert run from feet to inches?
A: Converting to consistent units (inches) ensures accurate trigonometric calculations since rise is typically measured in inches.

Q5: Can this calculator handle metric units?
A: Currently designed for imperial units. For metric, convert measurements to consistent units before calculation.