The first building with Granite® HDXtreme

ArcelorMittal Ghent’s Indi building in Belgium is the first building to be clad with Granite® HDXtreme. Located close to the industrial environment of the mill and the sea, Granite® HDXtreme was the ideal choice.

Three finishes, almost 50 colours

Created in consultation with architects and designers, Granite® HDXtreme is available in a huge palette of colours and three different finishes: satin, matt, and sparkling.

The satin finish is available in either 15 or 30 gloss units (GU) and has a grained texture. The matt (<10GU) finely wrinkled finish is available in four colours, and a sparkling, grained 30 GU finish is available in five colours. The latter are amongst the most attractive and sparkly steel finishes available on the market. More colours may be added depending on demand. The low gloss, matt finish is ideal for large flat panels and cassettes, while the standard and sparkling finishes are more suited to small panels.

9 additional colours have been added to the colour palette. Click on the image below to view.

Highly sustainable

The steel is designed for roofs and facades on buildings near the sea, and its performance is guaranteed for up to 40 years. Free of hexavalent chromium and heavy metals plus 100% recyclable, Granite® HDXtreme is highly sustainable: it has a lower CO2 footprint compared with alternative solutions such as aluminium.

ArcelorMittal launches Granite® HDXtreme for extreme climates!

ArcelorMittal Europe – Flat Products has created a new product designed for use in extreme climates. Granite® HDXtreme is the latest prepainted steel in ArcelorMittal’s organic coated Granite® range. Granite® HDXtreme is uniquely beautiful, resilient against corrosion, sustainable, and can be used in both indoor and outdoor applications. A three-layer coating system provides high levels of protection against UV and corrosion. This enables ArcelorMittal to guarantee the steel’s performance. Granite® HDXtreme comes in a vast palette of colours and three different finishes to make any project unique.

Three-layer coating system

The strength of Granite® HDXtreme comes from its three-layer coating system which ranges from 70 to 75 microns (µm) depending on the finish. Each layer performs a different but integral function.

The primer layer plays a key role in corrosion protection by ensuring the top coat adheres tightly to the underlying steel. On top of that is a polyurethane basecoat which ensures the steel’s durability and provides the final colour. The coating is finished with a layer of varnish which adds texture to the coating, increases durability and surface robustness, and enhances the UV weathering potential of Granite® HDXtreme.

Weathering resistance

Granite® HDXtreme already meets the requirements of the updated EN 10169 standard for continuously organic coated flat steels. Its exceptional UV resistance offers colour stability for many years. Granite® HDXtreme is also ready to pass the upcoming new RUV5 UV resistance standard when it is published later in 2021.

The coating has also been evaluated by exposing prepainted samples of Granite® HDXtreme to accelerated UV, humidity, and temperature variations for up to 4000 hours. Natural outdoor exposure tests have also been carried out at locations around the world.

Automatic guarantees

ArcelorMittal’s extensive experience and testing, including in highly corrosive seafront locations, translates into a long-term guarantee of up to 40 years for Granite® HDXtreme. The guarantee is applicable to roofs and facades as well as the installation of rooftop photovoltaic modules.

ArcelorMittal Europe Communications

Jeroen Op de Beeck and Philippe Vandenameele


Samples of Granite® HDXtreme are available through our online sample shop.