Small screens provide interesting viewing
Dominique Perrault's design for the facade of the Town Hall Gallery in Innsbruck uses moving panels to provide a sunscreen, creating an effect that is visually interesting but also practical
Think of a facade as a chequerboard, and the easiest way to change its appearance is by altering the colour of the squares.You could do this with photo-chromatic glass - that long-promised and still ludicrously expensive technology. But how much simpler it would be to have elements that slide across the surface. This is the case at the Town Hall Gallery in Innsbruck, Austria, designed by Dominique Perrault. The sliding elements are stainless steel sunscreens - the latest in a series of collaborations between the French architect and German manufacturer GKD (Gebr. Kufferath AG).
Perrault, who worked on the project with Munich practice Reichert, Pranschke and Maluche, says one of his goals was to achieve 'dynamic tension between presence and absence of architecture'. The seven-storey building houses city offices on its upper floors, while an intersecting wing connects to the town hall. In the gap is an area that will become a closed court with gardens and cafes. On the north side are a six-storey hotel and a two-storey shopping gallery.
Both of the hotel facades have 73 horizontally moveable 2.6m by 2.3m panels, made of a mesh type Omega 1508, whose density ensures the sunscreening effect. Their manufacturer says that light transmission at an angle of incidence of 50 degrees is similar to conventional sunscreens with almost closed lamellae, but with the advantage of an almost unobstructed view outwards.
The architect has made a feature of the eyebolts and springs that fasten the mesh tightly at top and bottom.
Another use of mesh on the building will create different impressions as the viewer's eye or the sun moves. On the shopping centre's glass roof, Perrault specified a relatively coarse type of mesh called Canisse, which has a slanted, not orthogonal, orientation.
This has a sunscreening effect while providing views outwards and setting up interesting reflections and Moiré effects. The weight of the mesh strips had to be balanced precisely and the strips stretched tightly to ensure the structure could cope with snow and other environmental conditions.