ST® panels coated with Muralys®: A spectacular colourful facade for Montpellier Arena

Detailed information

This new multi-purpose event centre is situated in Montpellier’s exhibition park and boasts its flexibility: it can be used as a theatre, as a sports hall, as an exhibition and congress centre, for concerts, etc. As a theatre, it offers seating for 14 800 people, for sport events 9800 spectators can be seated, and for exhibitions a total surface of 13 500m2 can be offered. With these dimensions, it is the second biggest arena in France, just after the Salle Omnisport in Paris-Bercy.

The building and its characteristic design do not leave one indifferent. On the contrary, it has a strong emotional impact that could be perceived as aggressive or even violent. These feelings are evoked by the materials employed as well as its colours: purple is a recurring element outside and inside the building. The use of gold in some parts provides warmth and takes the edge off this harshness.

The arena is based on a rectangular structure complying with the requirements of the client, ENJOY Montpellier, who commissioned a simple and practical building that can be used quickly. The surprising element of the building is the inclined front facade that rises out of the glazed entrance hall forming a canopy.

Race against time

One of the biggest challenges was the short construction period: not even two years were planned for the construction of this Arena. After breaking ground in the beginning of 2009, the building had to be ready a mere 21 months later, in September 2010, for a show hosted by ENJOY Montpellier.

The tight time schedule demanded efficient and economic construction methods, and, above all, close collaboration and exceptional involvement of all partners. The facade and roof were finished according to schedule thanks to the excellent and professional collaboration of the ArcelorMittal Construction team and the contractor.

The front facade – a giant amethyst

The inclined, purple front facade is made of 2588 ST® siding panels supplied by ArcelorMittal Construction, coated with the newly developed Muralys® technology: a total of 200 macro-photographs of two 50kg amethyst geodes imported from Brazil were printed onto the steel panels without any loss of definition.

These pictures cover the 4200 m2 of the canopy and provide the building with its characteristic purple colour.

The concept and layout of the siding panels has taken into account the possible constraints originating in production technology, installation, and architectural design.

The photo was divided into 22 working files, which again were converted into 444 print files to develop the layout plan. Then the 2588 steel elements were numbered according to this plan and installed on the metal frame.

The facades on the sides are based on ArcelorMittal Construction's GlobalWall CIN 327 that was modified and adapted to the fit the requirements of this project: The inner skin consists of perforated Supportwall 400.90 P panels, a layer of acoustic insulation, a metal frame of  45º inclined Z-profiles, two layers of thermal insulation, undulating Nergal steel profiles, and a 20mm counter frame forming cavity.

The outer skin is also made up of ST® siding panels, but a special effect is created thanks to their different sizes and colours: three different panel lengths, three different widths, seven colours, and two thicknesses convert the southwest and northeast facades into a spectacular visual highlight: the uneven surface composed of the 126 different siding panels creates shade and light reflections.

For this design, A+ architecture was inspired by a local fish - a certain type of bream. The differently shaped and coloured panels resemble its scales.

Roofing solution

For the 19 000 m2 roof, a complex photovoltaic solution was employed. The solar cells are installed on the GlobalRoof system which was – like GlobalWall - tailor-made for this project. The inner surface consists of perforated Hacierba trays with thermo-acoustic insulation, then Hacierco decking sheets covered by two layers of rigid thermal insulation. The roof is sealed with an integrated photovoltaic bitumen waterproofing solution on which 3128 photovoltaic cells on 280 crystalline panels are installed, producing up to 519 kWh.

Privacy & sun protection

A rounded volume stands out from one of the side facades just between the glazed reception and the changing rooms. ArcelorMittal Construction France developed a specific solution for the cladding of this part in order to meet the requirements: sun and visual protection from the outside without limiting the views from the inside.

Therefore, large vertically installed blinds made of perforated trapezoidal steel sheets (Trapeza 8-125-25 B, 1mm ) were employed. In line with the building’s colour concept and in order to achieve a better protection of the steel, these sheets were pre-coated 60µ in Gold 6995 on both sides.

As for the perforation, Type R8 T12 proved to be the perfect solution: consisting of a 8mm diametre hole with another hole just 12 mm from the centre of the first one, leaving 40% of the cladding transparent.