A supporting structure must have a minimum roof slope ratio of 1:12, or ~5 degrees. (however, we recommend a minimum of 10 degrees) to allow water to effectively flow over the sheet or through the flutes.
A 1:12 slope ratio means 1" of rise for ever 12" of run.
Plan arches within the cold-bending capabilities of your multiwall sheet. For proper cold bending, arches should always be formed parallel to the sheet ribs and the sheet length must be longer than sheet width.
Check roofing dimensions on-site. Complete all metalwork and painting before unmasking multiwall sheets, or before any sheet installation work.