How to Estimate Roof Covering Quantities
Measure sloping roof area, use manufacturer tile rates and separate field tiles from linear components.
Open →Roofing estimating guides
Roof covering, felt, battens and gutter quantity estimators.
What this topic covers
Roof estimating starts with the sloping surface, not just the building footprint. Field tiles and membrane are area quantities; battens, ridge, verge and guttering are different measurements.
Recommended estimating sequence
- Measure the job and keep the original dimensions.
- Calculate the base area, volume or length with compatible units.
- Replace variable defaults with the actual product or supplier information.
- Add a visible cutting, breakage or ordering allowance only where it is justified.
- Round the result to whole packs, bags or stock lengths at the purchasing stage.
Quantity estimating helps with planning and ordering. It does not replace structural design, project specifications, manufacturer instructions or regulatory approval where those are required.
How Roof Pitch Changes Roof Area
Why plan area underestimates a pitched roof and how slope length changes as pitch increases.
Open →