Roll Curving

Roll curving is typically used for corrugated profiles. Pre-curved corrugated roof cladding is used for bull-nosed veranda roofs, ridges, or roofs where the radius is less than the minimum required for sprung or draped curved roofs.

The sheets are passed through offset curving rolls, which progressively form curves in a wide range of radii down to 300 mm. There is, however, a straight portion of about 80 mm at each end of the sheet which may need to be trimmed off if a true curve is required.

Circular barns have been successfully clad with 0.4 mm steel for many years, but 0.55 mm steel or 0.9 mm aluminium should be used for roll-curved roofs subject to foot traffic. As roll curving is normally done with G300 steel or H34 aluminium, the lower yield strength of these materials must be taken into account when setting purlin spacings.

If the edge of the sheet is too flat or long, and at tight radii, rippled edges may result, and these should be dressed out using a dressing tool, or trimmed off before the sheet is installed.

Dressing Tool

Dressing-tool-curved roofs