Sculptural steel retains vibrant colour and gloss in Queensland sun

Winner of multiple industry awards, The Arbour is a kilometre-long walkway through Brisbane’s South Bank Precinct. An example of form meets function, this impactful piece of architectural art also provides visitors with essential shelter and shade. Design by Denton Corker Marshall is now a city landmark, with the walkway comprising of 443 galvanized steel columns wrapped in stunning bougainvillea, and a series of overlapping steel panels forming a ribbon-like canopy above.

Enduring performance of Dulux® Protective CoatingsTechnology

Originally constructed and coated in a Dulux Protective Coatings system in 2000, South Bank Corporation’s Arbour was assessed in 2020 and found to be showing some signs of colour fade and corrosion. Dulux Protective Coatings Business Development Executive, James Booth, inspected the structure and offered his expert advice and recommendations.

Brendan was impressed by the performance of the previous coating system over two decades, with the colour and gloss of the finish still in good condition.

“This coating system performed well, with an acceptable maintenance-free period of 20 years. The finish only required a regular pressure wash to restore colour vibrancy,” James reports.

“Evidence of corrosion was found in the overlapping sections of mild steel. This is to be expected because trapped moisture eventually penetrates coatings. This vapour transfer carries oxygen and atmospheric contaminants, such as salt and chlorides, accelerating the corrosion cell in the steel. Stainless steel fixings can also lead to dissimilar metal corrosion,” he explains.

A proven PUR4 coatings system for robust protection

The mild steel canopy panels were disassembled and transported offsite to the team of professional applicators at IPCQ for blast removal of the previous coatings before the new system was applied. In-situ spraying was not possible, due to the overlapping configuration of the panels and the sensitivity of the environment with the public and surrounding greenery in close proximity. Upon completion, the panels were re-installed in sections.

The Dulux® Protective Coatings Queensland team recommended the most robust protective coatings system available - a proven PUR4 system that meets Australian standards AS 2312:2014.1/Table 6.3.

• First coat: Dulux® Zincanode® 402 @ 75-microns (µm) DFT. This economical two pack zinc rich epoxy provides the steel with excellent corrosion protection.
• Second coat: Dulux® Duremax® GPE @ 125-microns (µm) DFT. This is an exceptional two-pack epoxy protective coating that has been specifically developed for Australasian conditions, utilising the latest advancements in epoxy technology.
• Topcoat: Dulux® Weathermax® HBR @ 100-microns (µm) DFT. This high build recoatable polyurethane topcoat retains colour and gloss, even in extended periods with extreme UV exposure.

Enduring colour vibrancy and gloss in a challenging environment

The Arbour is situated in a C3 corrosive environment. The nearby Brisbane River is a saltwater estuary, and therefore releases airborne salts that condensate on the finish. The vivid topcoat of Dulux® Weathermax® HBR in Sunflower will be exposed to Brisbane’s sub-tropical climate with extreme UV radiation. This highly durable coating has been formulated to resist fading, marking, graffiti attack and repeated exposure to cleaning agents. The finish is expected to retain colour and gloss with minimal maintenance.

“The canopy panels were re-installed with a fresh, new finish. I’m looking forward to watching the PUR4 coating system perform well for another 20 years,” James says.

Image courtesy of Kieran Larnach.