Metal Roofing Calculator
Calculate metal roofing sheet quantities from roof dimensions and pitch. Account for overlaps, waste, and screw counts. Free, no signup.
Roof Area Calculator
Calculate actual roof surface area from plan dimensions and pitch
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Metal roofing — did you know?
How metal sheets are measured
Metal roofing sheets are sold by length (e.g. 3m, 4m, 5m) with a standard coverage width (typically 1000mm profile, ~760mm effective after side laps). Calculate sheets needed: roof_width ÷ effective_width.
Side laps and end laps
Each sheet overlaps the next by one corrugation (side lap) and by 150-300mm at horizontal joints (end lap). Effective coverage width = profile width − side lap. For 1000mm profile with 250mm lap: 750mm effective.
Minimum pitch for metal roofing
Corrugated: 5° minimum (10° recommended). Standing seam: 3° minimum. Trimrib/Mini Orb: 5°. Below these, water can travel back up the corrugations under wind pressure.
Screw and accessory calculations
Approximately 8-10 screws per m² for corrugated, 3-5 per m² for standing seam (hidden fix). Add ridge caps, fascia trim, flashing, and closure strips — typically 10-15% of sheet cost for accessories.
Formulas used
Sheets needed
sheets = ceil(roof_width ÷ effective_width)
Effective width
effective = profile_width − side_lap
Sheet length
length = rafter_length + overhang + 50mm trim
Screw count
screws ≈ area × 8 per m²
Frequently asked questions
How do I calculate metal roofing sheets?
Divide roof width by effective sheet width (profile minus lap). For 10m wide roof at 750mm effective: ceil(10 ÷ 0.75) = 14 sheets per slope.
What is the overlap for metal roofing?
Side lap: one corrugation (~250mm). End lap: 150-300mm depending on pitch. Lower pitch = larger end lap.
Minimum pitch for metal roof?
Corrugated: 5° min (10° recommended). Standing seam: 3° min. Below these, water backs up under wind.
Best free metal roofing calculator?
One that handles sheet coverage, laps, screw counts, and waste. This tool does all, free.