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Roof Square Footage Formula:
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Roof square footage (RSF) is the actual surface area of a roof, which is typically larger than the building's footprint due to the roof's pitch or slope. It's an essential measurement 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 cosine function converts the pitch angle to account for the additional surface area.
Details: Accurate roof square footage calculation is crucial for determining the amount of roofing materials needed, estimating project costs, and ensuring proper planning for roofing projects.
Tips: Enter the building length and width in feet, and the roof pitch angle in degrees. All values must be valid (length > 0, width > 0, pitch between 0-89.9 degrees).
Q1: Why is roof square footage larger than the building footprint?
A: The slope of the roof increases the surface area compared to a flat roof, which is why we divide by the cosine of the pitch angle.
Q2: How do I measure roof pitch?
A: Roof pitch is typically measured as the angle of the roof slope or as a ratio of vertical rise to horizontal run (e.g., 4:12 pitch).
Q3: Does this calculation work for all roof types?
A: This formula works best for simple gable roofs. Complex roof designs with multiple slopes may require more detailed calculations.
Q4: Should I add extra for waste when ordering materials?
A: Yes, it's recommended to add 10-15% to your calculated square footage to account for cutting waste, overlaps, and errors.
Q5: What about roof features like dormers or valleys?
A: This calculator provides a basic estimate. Complex roof features require additional measurements and calculations beyond this simple formula.