Photo: © Felix Löchner Architekturfotografie

cube berlin is no ordinary glass-covered building. Located on the busy Washingtonplatz next door to Berlin’s central train station, the project is in the heart of the city’s business, government and cultural district. With its prominent location, 3XN Architects of Copenhagen designed cube berlin to be a show-stopping sculpture on the square.

But the all-glass design presented multiple challenges, including energy concerns and structural requirements. It was apparent from the start that the unique design of cube berlin required careful attention to product selection, ensuring that the right glass product would provide solar control to avoid heat gain/loss, as well as be structurally sound.

The solution was a double skin façade that uses coatings and PVB interlayers in a unique combination. To address the building owner’s strict energy requirements, Guardian Glass and Eastman selected, tested and utilized reflective solar coatings on the outer skin of the building while adding a Saflex solar-absorbing PVB interlayer to control solar heat gain in the cavity. Normally, these products are used on the inner skin.

Photo: © Felix Löchner Architekturfotografie

The project includes 8mm of UltraClear with HD66 on surface #2, Saflex Structural PVB, Saflex Solar PVB, 8 mm of UltraClear with HD66 on surface #4.

Through expert knowledge and testing and modeling, the team recognized the impact of merging structural and solar PVB technologies. The approach of dual technologies had to be taken to a national standards board, Zulassung im Einzelfall ZiE, where it was approved.

“To design such a complex product, you need real teamwork, which is exactly what happened during the design phase with the glass supplier, the PVB supplier, the architect and the façade consultant all working closely together,” says Joachim Fauth of Drees & Sommer, façade consultant on the project.