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Roof Square Footage Formula:
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Roof square footage calculation determines the surface area of a roof, accounting for its pitch or slope. This measurement is essential for roofing projects, material estimation, and cost calculations.
The calculator uses the roof square footage formula:
Where:
Explanation: The formula accounts for the increased surface area caused by the roof's slope. The steeper the pitch, the larger the surface area compared to the footprint.
Details: Accurate roof square footage calculation is crucial for proper material ordering, cost estimation, project planning, and avoiding waste or shortages in roofing projects.
Tips: Enter the length and width of your roof in feet, and the pitch angle in degrees. All values must be valid (length > 0, width > 0, pitch between 0-89.9 degrees).
Q1: Why do we divide by cosine of the pitch angle?
A: The cosine function accounts for the increased surface area of a sloped roof compared to a flat surface. A steeper pitch results in a larger surface area.
Q2: How do I measure roof pitch?
A: Roof pitch is typically measured as the vertical rise per horizontal foot (e.g., 4:12 means 4 inches rise per 12 inches run). You can convert this ratio to degrees using trigonometric functions.
Q3: Does this work for all roof types?
A: This formula works best for simple gable roofs. Complex roof designs with multiple sections, valleys, or hips may require more detailed measurements.
Q4: Should I add extra for waste?
A: Yes, roofing projects typically add 10-15% extra material to account for cutting waste, overlaps, and errors in measurement.
Q5: What about roof features like dormers or valleys?
A: Complex roof features require separate calculations. This calculator provides an estimate for basic roof shapes. Consult a professional for complex roof designs.