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Roof Pitch Formula:
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Roof pitch in mm/m is a measurement that expresses the steepness or slope of a roof. It represents how many millimeters the roof rises for every meter of horizontal run. This measurement is commonly used in construction and architecture.
The calculator uses the roof pitch formula:
Where:
Explanation: The formula calculates how steep a roof is by dividing the vertical rise by the horizontal run and scaling the result to show millimeters of rise per meter of run.
Details: Accurate roof pitch calculation is crucial for proper water drainage, material selection, structural integrity, and compliance with building codes. Different roof materials have minimum pitch requirements for effective performance.
Tips: Enter the vertical rise in millimeters and the horizontal run in meters. Both values must be positive numbers (rise > 0, run > 0). The calculator will compute the pitch in mm/m.
Q1: What is a typical roof pitch range?
A: Roof pitches typically range from 10 mm/m (very flat) to 500+ mm/m (very steep), with most residential roofs between 100-300 mm/m.
Q2: How does mm/m relate to angle or ratio?
A: Pitch in mm/m can be converted to an angle using trigonometry: angle = arctan(pitch/1000). A pitch of 1000 mm/m equals a 45-degree angle.
Q3: Why use mm/m instead of other units?
A: mm/m is commonly used in construction because it provides a clear measurement that's easy to work with and visualize on building plans.
Q4: What's the minimum pitch for different roofing materials?
A: Minimum pitches vary: built-up roofing (10-20 mm/m), metal roofing (50-100 mm/m), asphalt shingles (100+ mm/m), clay/concrete tiles (150+ mm/m).
Q5: How do I measure rise and run in practice?
A: Use a level and tape measure. For rise, measure vertical distance from eaves to ridge. For run, measure horizontal distance from outside wall to centerline.