Make a statement with a curved roof

• “Curved surfaces make a roofer’s job harder. Not only does the roofer need more experience and expertise to install curved roofs and lay, but curved surfaces also generally can't be walked on top of the way your roofer can on a flat or pitched roof.” 
• Curved roofs involve a tightness of radius within a small area of sheet, which can cause kinking and rippling. The minimum curve radius for each profile is restricted by the pan appearance of the roof sheet, while the maximum curve radius for each 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. For drape curved roofing, specific aesthetic requirements must be discussed with Dimond at the design stage. 
• Challenges can arise with long curve sheet lengths. “Some are difficult to transport due to shape and height.”

Curves in Invercargill

Intended to mimic the curves and undulations of the Southland landscape, the curved roof of this project makes use of conventional materials in an unconventional way. 

Using a selection of ColorCote .55 ZinaCore material in sandstone grey roll-formed to the Dimond Roofing Hi Five profile, the Dimond Roofing team in Christchurch brought the clients’ original sketch – resembling a squashed octopus with its never-ending curves in both form and elevation – to life. 

The material was run at Dimond Roofing’s Christchurch factory and the 34m sheets were transported to the site. 

The sheets are directly fixed to the central section over the apex of the roof and then slotted to allow expansion at the ends. There are no penetrations in the roof. Framing comprises parallel chord trusses allowing airflow to the roof space with vents included in the soffits to allow cross ventilation.

The Goodall’s curved-roof home in Southland

With few straight lines, Dimond Roofing’s expertise in curved roofing proved essential in this project in Mossburn. Featuring schist stone and timber logs grown by the owner, the home overlooks the stunning Lake Wakatipu.

Using Hi Five in Permanent Green ColorCote ZinaCore, which has been crimp curved to follow the roofline, the roof has been installed in a trapezoidal design. This profile gives a more modern feel than that normally achieved with the traditional stacked stone and corrugate combination that has usually been used in the area.

Whangārei: Dimond Roofing's longest curve roofing roll out to date

“What we have done in Whangārei, is instead of having our curving machine fixed to the ground in the factory, giving us a limitation in curved sheet lengths due to space, we have fixed our curver machine on a steel plate and added a 30+ metre extension power cord,” says Gordon.