Calculate roofing materials — squares, shingle bundles, underlayment, ridge cap, and total cost. Supports all roof pitches, types, and materials with step-by-step breakdown.
A new roof is one of the largest home improvement investments — typically $5,000–$15,000 for an average home. Accurate estimation is critical whether you're getting contractor bids (you need to understand what they're quoting) or planning a DIY project. This guide covers every aspect of roof material estimation from pitch factors to material comparisons.
You can't simply use the building's footprint because roofs are sloped. The actual surface area depends on the pitch (steepness). The footprint area is multiplied by a pitch factor — a number greater than 1 that accounts for the slope. Steeper roofs have higher pitch factors and require more material.
| Material | Cost/Square | Installed/Sq | Lifespan | Weight |
|---|---|---|---|---|
| 3-Tab Asphalt | $80–$120 | $150–$250 | 15–25 yr | ~200 lbs/sq |
| Architectural Asphalt | $100–$180 | $200–$400 | 25–40 yr | ~300 lbs/sq |
| Metal Standing Seam | $250–$450 | $300–$700 | 40–70 yr | ~100 lbs/sq |
| Clay/Concrete Tile | $300–$600 | $400–$1,000 | 50–100 yr | ~900 lbs/sq |
| Slate | $600–$1,200 | $800–$1,500 | 75–150 yr | ~800 lbs/sq |
| Wood Shake | $200–$400 | $350–$600 | 20–40 yr | ~350 lbs/sq |
Underlayment goes under shingles as a moisture barrier. Synthetic underlayment ($40–$80 per roll covering 10 squares) is the modern standard — lightweight, tear-resistant, and slip-resistant. Traditional 30 lb felt ($15–$25 per roll) works but is heavier and tears more easily. Ice and water shield is required along eaves and in valleys — it's a self-adhering membrane that prevents ice dam leaks. Plan for 2 rows of ice shield along every eave edge.
Ridge cap shingles cover the peak of the roof. Measure the total ridge and hip length — each bundle of ridge cap covers about 20–33 linear feet (varies by brand). Starter strip runs along the eaves and rakes and is essential for wind resistance. One roll typically covers 100 linear feet. Measure the total perimeter of the roof edge for starter strip quantity.