Construction & Trade
Roofing Calculator
Calculate roofing materials (sheets or tiles), accessories, and cost based on roof area, pitch, and material type.
How this calculator works
Adjusts the plan area to actual roof surface area using the pitch factor (plan area / cos(pitch angle)). Divides by the coverage area per sheet or tile to get the quantity. Adds the waste factor and calculates accessory requirements (ridge caps, screws, sarking).
Flat plan area of the roof (footprint)
Steeper pitch = more actual surface area
Colorbond sheets ~$20-35 each. Concrete tiles ~$1.50-2.50 each.
10% for simple roofs, 15% for complex hips/valleys
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FAQ
Frequently asked questions
How many Colorbond sheets per square metre?
Standard Colorbond corrugated sheets (762mm cover width) require approximately 1.3 sheets per m² of actual roof area. Custom Orb and Trimdek have different cover widths — check the BlueScope specification for your profile.
How many roof tiles per square metre?
Concrete tiles: approximately 9-10 tiles per m². Terracotta tiles: approximately 11-13 per m². This varies by tile profile and overlap. Always check the manufacturer's specification.
What is the cheapest roofing material in Australia?
Colorbond steel is typically the most cost-effective for new builds at $50-$80/m² installed. Concrete tiles are $60-$90/m² installed. Terracotta tiles are $80-$130/m² installed. Metal is lighter and faster to install.
How long does a Colorbond roof last?
BlueScope offers a 25-year warranty on Colorbond steel. In practice, Colorbond roofs in Australia commonly last 40-60 years with minimal maintenance. Coastal and industrial environments may reduce lifespan.
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