The NZ Metal Roof and Wall Cladding Code of Practice is a comprehensive design & installation guide, and a recognised related document for Acceptable Solution E2/AS1 of the NZ Building Code.
All roof cladding with a pitch of less than 8° must be provided with turn-downs after the roof is fixed, using special tools to ensure water flows directly into the gutter.
As the corrugated profile cannot be satisfactorily turned down, it is not permissible to terminate this profile below 8°. See 15.1 Curved Roofs.
Distortion should be avoided because it causes ponding and the collection of dirt, which in turn causes corrosion.