Roofing Calculator
Calculate roofing materials (sheets or tiles), accessories, and cost based on roof area, pitch, and material type.
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
How It 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).
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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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