How to choose the best corrosion-resistant metal for your environment

No matter where you build in Australia, exterior perforated metal will always be at the mercy of the elements. Coastal salt air, intense UV, strong winds, and sudden storms make our climate especially tough for property developers, architects, and specifiers to ensure buildings stand the test of time. Which corrosion-resistant metal is up to the challenge? Here are our top picks of the metals we use for perforation, best suited to Australia’s harsh conditions:

Best corrosion-resistant metal for coastal and marine architecture: Aluminium

The corrosive effects of saltwater, UV, and humidity make coastal environments particularly demanding. If your project is affected by these conditions, we recommend aluminium.

Aluminium is the popular go-to for projects affected by coastal conditions. It is naturally rust-resistant. However, in its natural state, aluminium will eventually oxidise – which is why it is either powdercoated with colour or anodised to enhance weather protection.

Advantages of aluminium include: 

• It is durable and strong but very lightweight – making it ideal for applications where weight is a factor. 

• 100% recyclable – at Arrow Metal, we perforate aluminium that’s at least 54% recycled content.

For certain projects, stainless steel may also be an alternative. Grade 316 stainless steel is resistant to corrosion. However, it can develop what is known as ‘tea staining’ – a brown, cosmetic discolouration that affects the metal’s surface. For this reason, if stainless steel is your choice, we would always advise finishing the metal with a protective coating.

Example projects

Pittwater House, Northern Beaches, Sydney

Coastal corrosion was a significant consideration for the multimillion-dollar upgrade of Sydney school Pittwater House. Located in Collaroy on Sydney’s Northern Beaches, the school needed a cost-effective, long-lasting solution to modernise its outdated classrooms. Our perforated aluminium was the answer, clad over the existing red brick facade to create a brand-new look. The aluminium is corrosion-resistant to the coastal air and powdercoated in the school’s colours for increased protection and visual appeal.

Brisbane Ferry Terminals 

For the upgrade of Brisbane’s ferry terminals, marine-grade aluminium panels ensured longevity and durability on the water. We perforated over 135 sheets of aluminium for the project, many of which were unique in design and CAD drawn.

Best corrosion-resistant metal for sunny environments: Aluminium and brass

UV rays and intense heat can cause severe damage to certain metals over time. For perforated metal that can cope with sun exposure, we recommend:

Aluminium

Aluminium’s thermal properties help dissipate heat quickly, making it the top metal choice for sunny areas and areas where the metal surface may be touched, such as balconies, balustrades, fencing, shutters, and screens.

It is also UV resistant and will not crack or break even under extreme temperatures.

Brass

Brass is also a corrosion-resistant metal that dissipates heat quickly, making it a great metal choice for a standout statement exterior feature in sunny areas. Over time, it oxidises to develop a unique protective patina, giving it that characteristic, sought-after ‘aged’ appearance.

Example projects

Canterbury South Public School

Solar protection was a major challenge for the redevelopment of Canterbury South Public School. Our perforated aluminium solved the problem, with perforations adapted to shield students on the sunny elevations of the building whilst adding light and warmth to the shaded classrooms.

Chatswood home balcony 

At a home in Chatswood on Sydney’s Lower North Shore, our perforated brass created a rich aesthetic for the outdoor balcony balustrade, adding charm and luxury appeal.

Best corrosion-resistant metal for windy and stormy regions: Aluminium and Corten steel 

Wind-driven conditions need a strong, corrosion-resistant metal to cope with fluctuating forces. We recommend:

Aluminium

Once again, aluminium is a top choice, as it can withstand wild, windy, and very wet weather. Aluminium perforated metal is a perfect exterior solution for stormy regions. Not only is it protected against moisture, but the metal’s perforations also help filter the wind, resulting in minimal wind noise.

Corten steel

If visual impact is a key project goal, consider Corten steel or ‘weathered steel’. It will not bend in high-pressure conditions and oxidises quickly to develop a protective orange patina, making it an attractive corrosion-resistant metal for exterior features that only gets better with time and weather exposure. Corten steel is best suited to locations with alternating windy/wet and dry weather conditions to ensure the patina develops evenly.

Example projects

NUspace, University of Newcastle

Windy conditions meant the external learning booths at the University of Newcastle’s NUspace building needed careful engineering. We perforated 3mm aluminium panels to create the booth walls, using a perforation design to ensure maximum wind resistance according to wind tunnel testing criteria. The building achieved a 5 Green-Star Rating and won a haul of architecture awards.

Mascot Station 

Although this is an interior application, our project at Mascot Station shows just how effective Corten steel is at making an impact. It was used to bring local aviation history to life – an inspirational idea that could also be used externally for facades.

Need advice on which corrosion-resistant metal to choose? 

Talk to our team about your project and its environmental conditions. We’ll advise on the best metals for perforation that meet your performance, visual, and budget requirements.

Main image: Waitara Station featuring Arrow Metal’s perforated metal ceiling