Roll to Roof: The future of large-scale industrial roofing installations

The country’s largest industrial roof has been installed using an innovative, safer and more cost-effective at-height system never used before in New Zealand. The roof on Foodstuffs’ new distribution centre at Auckland Airport will become home to the country’s largest solar panel farm to be installed later this year.

Years of research and exhaustive trials have preceded the roofing of the centre: the roll-forming machine being literally containerised and craned to roof height, enabling Kiwi Roofing installers to feed the 78 metre long sheets of quick fix Dimondek 630 directly into position.

Normal methods of roofing this 77,500sqm roof – equivalent to around nine rugby fields in area – could not be deployed so Fletcher Steel’s Dimond Roofing and RANZ member, Kiwi Roofing Ltd came up with a novel approach.

From the outset, (the client had selected the DD630 profile), the scale of the job posed some significant challenges – namely the long sheet lengths. The shortest 17m sheet was manageable on site but the rest ranging from 25m to 75m in length meant site limitations for setting up the DD630 rollforming machine and where could the sheets be stored before lifting to the roof? Early discussions with the main contractors on the construction programme, the site constraints with the footprint of the rollforming machine, the logistics of transporting 28m long sheets around the site and the access and size of cranes needed to lift sheets onto the roof meant another approach was needed.

Paul Connell, Managing Director of Kiwi Roofing says discussions began with Dimond about the possibility of roll forming to the roof. It began with developing a conceptualised frame structure with a platform that the roll forming machine would sit on after being lifted to roof height by a crane and the product run directly onto the roof was conceived.

This concept seemed initially to be the best solution but it became apparent that the platform would have to be moved frequently - more than originally anticipated and that as construction of the building progressed further along the site, the height of the building also increased which meant the platform height would need to increase accordingly.

How safely could this be achieved and what impact would ground conditions have on this plan?

Says Paul: “After a fair amount of discussion we came up with the concept of suspending the rollforming machine in its container and following discussions with Auckland Cranes as to whether this could be done – and with Dimond that it was possible to do, we had several design meetings culminating in a lifting platform to accommodate both the rollforming machine and the de-coiler.

“Once the engineers finalised the design and the building of the platform commenced, Kiwi Roofing focused on the health and safety aspects: the methodology deviated significantly from conventional roll forming operations. Clearly defining each parties’ functions and overarching health and safety responsibilities was critical.

“We still could only roll form from one side of the site so getting the longest sheets up and over the ridge and down the other side safely on a building that was over 200m wide became the next challenge.

“Handling a 75m sheet safely requires a lot of physical labour which meant there were a lot of men and women on the roof who had no previous experience working at height. Mitigating any risks these individuals could potentially be exposed to was paramount to everyone involved. We even went as far as having the egress from the scissor platform modified so they could walk from the scissor platform onto the roof”.

Jason Whiteman (Dimond Roofing) spoke to Rooflink from the manufacturer’s perspective saying a roof of this size has costly logistical and safety challenges with large mobile cranes and coordination between roofing and other trades on site. The concept of “roll to roof” was offered as a solution to this project.

“The system streamlines the two-step process of rolling and shaping the steel roof at ground level and craning it into place, into one continuous process that is completed on the roof, he said.

“The system has never been used in New Zealand before and the companies involved wanted to try something innovative and the scale of this roof made the project a perfect pilot for the system”.

Several modifications were made by Dimond to the roll former. Extensive work was required to allow machine operators remote access from the roof to the machine’s controllers. All this had to be done while the machine remained in service on other jobs leading up to starting on the Foodstuffs site. Once the platform was ready two test lifts took place to ensure everything worked as intended.

When the start day arrived an exclusion zone almost the size of an Olympic swimming pool was set up around the lift area involving two cranes and all the associated equipment required plus all the coils. There was intense scrutiny on the operation and most key stakeholders had H&S representatives on site to observe. The first run went off without any issues and after the coil exchange was completed it was obvious all the planning and collaboration had been a success.

From Kiwi Roofing’s perspective, planning was key to bringing this unique project to a successful conclusion, safety being key to installing the sheets flowing over a series of rollers gutter-to-gutter on this significantly large roof, safety mesh, underlay and clips installed prior to installing the sheets along the roof. Two cranes supported the suspended containerised roll forming machine which was anchored by several ten tonne concrete anchors; the system can be utilised using one crane in the event that there is not enough room on site for two.

“One of the biggest challenges with installing a roof like this is wind”, says Paul Connell. “When the wind is blowing it’s not safe to be craning sheets of steel up to 16 metres in the air. With roll to roof and a moderate wind it didn’t delay the process.

“We had a team of up to 15 installing the roof starting in July 2019 and finishing in March this year, the system proving to be safer and faster, saving an estimated two months’ time on installation”.

The roofing element of building the distribution centre was carried out while the building was under construction, the method allowing the steel fabricator to work unimpeded by the Kiwi Roofing team. As steel sections became available the roll to roof process could be completed.

Lindsay Rowles, General Manager of Membership and Property at Foodstuffs North Island says the installation of the roof at the new Foodstuffs distribution centre had been a massive task.

“The new roof will serve as the foundation for New Zealand’s largest solar panel farm which is set to be installed later this year.

“Through our partnership with Dimond Roofing and Kiwi Roofing we are proud to use safer and more cost-effective tools within the building process and are excited to incorporate further innovations into the build”.

Located at The Landing Business Park, Auckland Airport, the Foodstuffs new distribution centre is set to be completed and opened by the end of this year.

Key facts

77,500sqm roof comprising 108km of roll formed steel roofing (more than 1300 sheets

The roof manufacturing was completed by a team of 15 from Dimond Roofing and 14 from Kiwi Roofing comprising installers and labourers

The roof was installed over eight months – two months faster than usual methods

The process was safer – eliminating some of the risks associated with craning roofing sheets into place

This is the first time this method has been deployed in New Zealand so there is potential to apply this process to a range of roof sizes and designs

A highlight of the RANZ conference at Wintec, Hamilton in 2005 was the unveiling of Dimond’s portable, on-site rollforming machine which members viewed in action producing a trough section sheet – heralding what has become commonplace now on many projects around the country. The innovative development of bringing the rollforming machine to roof height introduces many efficiencies over conventional site roll forming with its particular suitability for large scale projects.