Start with the roof geometry, then move through field tiles, membrane, tile battens and finally the rainwater run. Each calculator keeps product-dependent rates and allowances visible instead of hiding them in generic defaults.
The output from one stage often becomes the measured input for the next. The calculators deliberately stop short of choosing a product specification for you.
Convert a simple symmetrical gable footprint and measured pitch into true sloping roof area, or calculate one rectangular roof slope at a time.
Use the measured sloping area with the exact tile manufacturer’s tiles-per-m² rate. Field tiles stay separate from ridge, hip, verge and other special fittings.
Enter the actual effective installed coverage per roll after the membrane system’s required laps. Gross roll size is not treated as usable coverage by default.
Use the actual first-to-last tile-batten datum distance, row length and manufacturer maximum gauge. The tool rounds intervals up and reduces the working gauge evenly when required.
Estimate gutter stock, straight-run joints and spacing-based fascia support positions from the measured run, actual stock length and the chosen system’s maximum bracket spacing.
The individual calculators are best for checking one quantity. Use the project planner when you want roof area, field tiles, battens and felt in one wider estimating route.
Use these when the measurement or product-rate step needs more context before you put numbers into a calculator.
Roofing systems vary by product, pitch, headlap, gauge, exposure, fixing specification and roof geometry. These calculators therefore use measured geometry and the current product/system data you supply rather than hiding one “standard” set of assumptions inside the answer.
These are quantity estimators, not roof-design, structural, fixing, drainage-capacity or specification tools. Verify the final system against drawings, current manufacturer instructions and site conditions before ordering or installation.
