ROOFING RESOURCES
Roofing measurement and estimation FAQ
Direct answers about roofing squares, aerial measurements, pitch and material allowances.
How many square feet are in a roofing square?
One roofing square equals 100 square feet of roof surface area. Sloped surface area can differ from the horizontal footprint.
What waste factor should I use for a hip roof?
The allowance depends on layout, material system and installation details. Compare labeled scenarios, then confirm quantities against the selected product and project. A roof type alone does not establish a universal percentage.
How accurate are aerial satellite roof reports?
Accuracy depends on the imagery, roof visibility, geometry and measurement method. Review the report’s sources, confidence and limitations; a confidence grade alone does not establish a universal percentage error.
How do I calculate roof area from a footprint?
Multiply horizontal projected roof area by √(1 + (rise ÷ run)²), using the same units for rise and run. Include relevant overhangs and calculate facets with different pitches separately.
Should I apply pitch to an already measured roof surface?
No: an area measured along the sloped roof surface already accounts for pitch. Divide its square feet by 100 to get net roofing squares before waste.
Can I get a replacement range from a grade-D report?
Grade-D reports withhold replacement ranges because the available evidence is insufficient. Accepting a warning cannot unlock a range; a new report version must pass the applicable quality checks.