Folded Glass Façade Checks All the Boxes

Strength, Sustainability, Ventilation, Daylighting, Thermal, Acoustic

When Lidl Schweiz outgrew its main building in Weinfelden, Switzerland, a new two-story, 19,000-m2 headquarters was built across the road. The compact facility would address multiple concerns with its design and use of a glass façade. First, it would be built to the Swiss Minergie standard, meeting stringent requirements for sound insulation, construction ecology, and daylight harvesting. Second, the design features two upper levels of transparent glass balanced over a recessed ground floor, with the idea to use structural glass that would be as clear and neutral as possible.

To address these concerns, Swiss architects Itten+Brechbühl AG proposed a folded glass façade built of four 34-mm thick Ultrastrong laminated safety panes, over 1000 pieces with the size about 960mm x 4300mm, featuring Saflex® Structural (DG41) PVB interlayer. SILVERSTAR ZERO Eplus insulating glass makes up the panes and was an ideal selection, as it ranks among the most energy-efficient multiple-insulating glazings and is well suited to meet the Swiss Minergie standard.
 

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Dileis GmbH developed the plans for the façade, and the glass was fabricated by Glas Trösch. The glass makeup used ensures structural strength and provides the exceptional color neutrality desired by the architects. Specifying Saflex Structural was advantageous for reducing deflections and overall product weight and provided improved edge stability compared to regular PVB, which was essential for the exposed edges of the folded façade design. Plus, it has broader compatibility with frit/coating.

Since the two upper levels house office space in an open-concept design encased in a glass façade, it was important that the window panes met sound insulation requirements for acoustics. The clarity of the glass belies its structural strength and ensures occupants can take advantage of natural light. The curtain wall protects the insulating glass and textile sun protection behind it as well as provides thermal benefits from continuous ventilation.

As a result of the overall design and the glazing choices, the folded glass façade of the eco-friendly building has been awarded the Gold Certificate by the DGNB German Sustainable Building Council.