Store façade reflects city’s textile heritage

Courtesy of Interpane

“The glazing is a double-skin façade. Internal insulating glass with ceramic frit; external single laminated, heat-treated [glass] with our special ipachrome coating. It was the first time that we produced a partial coating by masking parts of the glass surface and supplied a full-size ipachrome coating. After the coating process by magnetron equipment, we remove the mask and get the result. The coating is between the two glass sheets protected.” – Gregor Ranner, head of sales, Interpane

The basics:

The John Lewis department store in Leicester, England, features a transparent, lace-like patterned glass façade backlit at night in 256 colors. Interpane of Germany created the pattern with its ipachrome design, a chrome coated multilayer system. Applied using the sputter process, ipachrome makes the pattern appear like a highly reflective conventional silver mirror from the outside. The design forms flowing transitions between the multiple panes, producing the appearance of a single unit. With its variations in transparency, the double-layered façade serves as solar and visual protection for the store interiors while opening them to city views and natural light. Inspiration for the lace-like wall came from Leicester’s and John Lewis’ rich history in textile manufacturing and the city's large Indian population in translucent saris. The 25,000-square-meter store was completed in September with the façade costing about $13 million.

The players:

Architect, Foreign Office Architects, London; general contractor, Sir Robert McAlpine Ltd., London; façade fabricator, Seele GmbH & Co. KG, Germany; glass fabricators, BGT Bischoff Glastechnik AG, Germany, and Steindl Glas, Austria; glazing contractor, Seele GmbH & Co. KG; glass coating supplier, Interpane Glas Industrie AG, Germany; owner, Hammerson PLC, London.

The glass and systems:

More than 5,000 square meters of glazing and 625 panes measuring 2.4 meters by 5.4 meters comprise the façade. Two layers of 10-millimeter-thick, heat-strengthened glass make up the laminated panes. The three floors of curtain wall were hung from the top and horizontally glued, eliminating movement joints at each floor. At the same time, installers fixed horizontal tension cables behind the façade to squeeze the panels tightly together. In this way, hundreds of horizontal and vertical joints were halved in width to 24 millimeters, creating a visually seamless wall.