Construction World April 2015

PROJECTS AND CONTRACTS STATE-OF-THE-ART ROOF

When the time came for Amalgamated Beverage Industries (ABI) to refurbish the roof of its bottling plant in Devland, it looked for a business that has earned a reputation in the industry for its expertise in dealing with unusual roof designs.

with any older facility, the plant’s roof was reaching the end of its natural lifespan, having become victim to corrosion, caused by the harsh vagaries of South African weather. The engineers who originally built it adopted an ‘origami style’ for the roof, which utilises very specifically folded steel that is designed to be self-supporting. When it came time to replace the roof, says David Williams, managing member and technical sales director at R&D Contracting, retaining the origami style was not cost-ef- fective. Although self-supporting, it utilises large volumes of steel. “We decided to base the design of the new roof on a previous project we had completed for ABI at its Wadeville Coca Cola canning plant,” he says. Williams explains that the project currently sees R&D removing around six tons of steel from the roof every week. This is being replaced by a far lighter zinc aluminium composite – known as zinc alum – that is just 0,55 mm thick. He states that on average, the company is installing between 12 and 18 metres of the new roofing per day. The galvanised support beams are specially designed for the project, and are certified by engineers, prior to implementa- tion, he adds. Williams also points out that R&D is using sisalation underneath the zinc alum roofing for the purposes of insulation. This is also far thinner than the previous insulation used, but thanks to a reflective coating on the outside, is just as effective at keeping the factory cool. “The sisalation is a key innovation here, as it improves vastly on the old roof, which utilised sponge, fitted between double steel, for insulation purposes. Sponge works fine in a new roof, but as the roof ages, it becomes easier for this sponge to get wet. I can tell you that vast tracts of wet sponge add an enormous additional weight load onto the roof. Fortunately, this is all negated now by the far lighter zinc alum roofing and

Since the ABI plant had been built using a very specific ‘origami style’ roof, a contractor with both this specific proficiency and an exten-

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sive track record in the commercial and industrial maintenance sector was required.

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FROM TOP TO BOTTOM: The origami steel roof, showing signs of serious corrosion. Opal White polycarbonate sheeting, with sisalation visible underneath. Zinc alum 0,55 mm roof sheeting. Based on previous experiences with the organisation, ABI turned to R&D Contracting to solve its roofing challenges. The ABI bottling plant in Devland is a world-class manufacturing site, which has been producing cool drinks for the South African market for decades. However, as

the sisaltion we are using instead.” Intense preparation

Williams explains that the project is expected to take approximately 10 months from site set-up to conclusion. This, he adds, does not include the additional time required for preparation and fabrication prior to starting.

CONSTRUCTION WORLD APRIL 2015