Roofing Calculator - Shingles, Materials & Cost

Roof Surface Quantification & Material Optimization Framework

Core Conversions

• Squares = (Net ft² ÷ 100) × (1 + Waste%)
• Bundles = Squares × BundleFactor (3‑tab≈3, Arch≈3, Premium 4–5)
• Pitch Adj = Horizontal Area × PitchFactor (table embedded in calc)

Waste Benchmarks

• Simple gable 8–12%
• Hip / multiple valleys 12–18%
• Cut‑heavy (dormers, angles) 18–22%

Material Layer Stack

• Deck → Underlayment (ice & water shield at eaves/valleys) → Starter → Field shingles → Flashings → Ridge ventilation → Ridge cap
• Underlayment rolls ≈ (Adj ft² ÷ 400)
• Nails (lbs) ≈ Squares × 0.6 (architectural @ 4 nails) adjust +25% high wind spec

Cost Control Levers

• Bundle cost vs labor ratio: if labor >60% evaluate higher grade longevity
• Ventilation upgrade reduces premature shingle aging (heat cycling)
• Strategic metal in valleys extends life; selective not full metal roof

Failure / Risk Signals

• Granule loss concentrated in drip line → ventilation or UV overexposure
• Wavy courses → deck moisture / improper nailing
• Attic dew / frost → inadequate intake vs exhaust balance

Upgrade ROI Snapshot

• Synthetic underlayment: +5–8% cost → ↑ tear resistance / dry‑in time
• Ridge vent + soffit: payback via extended shingle service life
• Cool roof pigments (hot climates): reduce cooling load 5–10%

Quick FAQ

• Why pitch factor? Converts plan rectangle to sloped surface area.
• Re‑roof vs tear‑off? Second layer saves labor but can void warranties / adds weight.
• When to replace? Curling edges + widespread granule asphalt exposure >10% field.

Action Tip: Lock waste % after section modeling; changing late cascades through bundles, ridge and accessory counts.