Providing greenspace in an innovative way, the new city hall in Herstal, Belgium features a chequered facade of individual greenwall ‘tiles’, mixed with glass and solid panels.

This unique green facade design comes from Frédéric Haesevoets Architecture. Of the 2500 m² of facade, approximately 1000 m² of the building’s exterior is covered with a patchwork of vegetation.

Generally, vegetated facades are designed more as monolithic walls. Here however, each square is independent and autonomous. This not only means that individual greenwall squares can be replaced if necessary, but it also means that a wide variety of different plant species can be used across the facade.

In total, 23,000 plants were used in this facade design, with different species selected not only for their buffering and water retention capabilities, but also according to the orientation of each panel to the sun. During the design process, the architects took on board the advice of Louis Benech, the French landscape gardener who renovated the Tuileries Gardens in Paris.

The greenwall squares each have their own water supply at the upper tip of each panel, allowing for a water recovery system that operates in a closed circuit. Furthermore, the City Hall is very low in terms of its energy consumption, in part because the planted squares help to cool the building in the summer and insulate in the winter – much like a green roof!

Photography © Christophe Vootz 

(Source: architectura.be)