Recommended Curve Radius
Minimum Radius
The minimum curve radius for each profile is restricted by the appearance of the roof sheet. As the radius is reduced the “pan” of the profile will begin to exhibit compression ripples that will detract from a clean appearance, and eventually reach a level that is generally regarded as unacceptable.
The minimum radius given below for each profile, together with the purlin spacing recommended for use at the minimum radius, will ensure the clean appearance of the drape curved roof with minimal ripple effect. Specific aesthetic requirements for drape curved roofing must be discussed with Dimond at the design stage.
Maximum Radius
The maximum curve radius for each profile is restricted by the need to have the selected profile roof-sheeting reach its minimum recommended pitch at the gutter line for the profile used.
This restriction ensures large radius “flat” roofs are not used.
In addition, the maximum radius limitation and profiles given below for Corrugate profile ensures that water catchment on the low pitch area of the curve will not overfill the profile valleys due to inadequate run-off.
Drape Curved System – Recommended Profiles and Radius Limitations
| Recommended Profile | Min. (m) Radius G550 Steel 0.40mm | Min. (m) Radius G550 Steel 0.55mm | Min. (m) Radius H36 5052 Aluminium 0.70mm | Min. (m) Radius H36 5052 Aluminium 0.790mm | Min. (m) Radius Natural Lighting 1.1mm | Min. (m) Radius Natural Lighting 1.4mm | Min. (m) Radius Duraclad 1.7mm | Max. (m) Radius |
| V-Rib | 20 | 16 | 20 | 16 | 12 | 14 | 20 | Note 2 |
Note 1: Maximum radius for Corrugate is determined by the maximum run of roof that is below the minimum pitch, measured from the apex, shall not exceed 5m. Maximum radius may be further restricted by the criteria in Note 2.
Note 2: Maximum radius determined by the need for the roof pitch to reach the minimum requirement for the profile at the gutter line. Maximum radius will therefore depend on the building width.
Note 3: For the recommended maximum purlin spacing, the unrestricted access roof purlin spacing should be used to achieve a smooth curve
Note 4: The Baby Corrugate profile is not recommended for use as a roof product. It is only intended as cladding.
Note 5: DD630 is also available in 0.48mm thick steel and will achieve the same radius as 0.55mm steel.
Note 6: For the radius on aluminium, please call Dimond to discuss.
Note 7: DD630 Natural lighting sheets are not intended for use by themselves and must have support on the side lap from the steel sheet.
Note 8: Check suitability using section 2.1.3.1 - Table 2.1 of the Dimond Roofing & Cladding Technical Mnaual
N/R = Not recommended; N/A = Not available
Radius Calculation
