Why your roof is larger than your home's footprint
A flat roof directly over a 2,000 sqft home would be 20 squares. But because roofs are sloped, the actual surface area is always larger than the plan view. The steeper the pitch, the bigger the difference:
| Roof pitch | Slope multiplier | Example: 2,000 sqft footprint |
|---|---|---|
| 4/12 (low slope) | 1.054 | ~21 squares |
| 6/12 (common) | 1.118 | ~22 squares |
| 8/12 (moderate) | 1.202 | ~24 squares |
| 10/12 (steep) | 1.302 | ~26 squares |
| 12/12 (very steep) | 1.414 | ~28 squares |
Add roof overhangs — typically 12–24 inches beyond the exterior wall — and the actual roof area is larger still. This is why accurate measurement matters: a contractor estimating from a home's footprint without accounting for pitch and overhang will either under-order materials or give you an inaccurate price.
How Atlas Roofing measures your roof
Atlas Roofing uses Roofr — an aerial measurement platform that generates precise square counts from satellite imagery combined with pitch measurement. The measurement report identifies every roof plane, its exact dimensions, and the total squares including waste factor for each plane. This is the same tool used by major insurance companies to measure roofs for claims.
You'll receive the measurement report as part of your estimate — you can see exactly what we're working from. There are no surprises about square counts after the job starts.
Waste factor — why you order more than the measured area
Shingles are cut to fit at hips, valleys, ridges, and edges — these cut pieces are waste. Complex roofs with many valleys and hips have higher waste factors than simple gable roofs. Standard waste allowance is 10–15% for simple roofs, 15–20% for complex roofs. Your estimate should reflect appropriate waste — a contractor who orders exactly the measured square count will likely run short.
Reading your estimate: The square count on your estimate multiplied by the price per square equals the material and labor subtotal. If a contractor doesn't show square counts, ask — you're entitled to know the basis of the pricing you're approving.