Reviewed, sourced guidance
Estimate roof batten length from product data
Direct answer
If the product data states linear metres of battens per square metre, multiply that rate by net sloped roof area. This is a planning quantity, not a batten layout, fixing design or cutting schedule.
Batten rates are system-specific. The estimator accepts linear metres per square metre from the product data instead of assuming a gauge.
Key takeaways
- Use a rate for the exact roof covering system.
- Manufacturer data can list different batten rates by headlap.
- The calculator reports net linear length only.
- Batten sizing and fixing need the system specification.
Use the system rate
Marley lists Duo Modern batten rates of 2.9 linear metres per m² at 75 mm headlap and 3.1 at 100 mm headlap.
These figures apply to the named product data. They should not become a default for other tile or slate systems.
- Check the product, headlap and current data sheet.
- Calculate area for each roof plane before applying the rate.
- Keep the rate’s unit with the value when copying it.
Sources for this section: Marley, Duo Modern product data (observed 2026-09-25)
Quantity is not a design
A linear-metre estimate does not state batten grade, size, support spacing, fixing or edge details.
Those decisions belong to the exact system guidance and competent project specification.
- Do not use this number as a shopping list without review.
- Check the required battens per rafter spacing in the product guidance.
- Add cutting and detailing only through a reviewed take-off.
Sources for this section: Marley, Duo Modern product data (observed 2026-09-25)
Next steps
- Enter the current system rate if it is stated.
- Have the final batten schedule checked with the chosen product specification.