a new level of double-skin glass façade
cube berlin is the sculptural centerpiece of one of the most prominent squares in Berlin. Built specifically to support today’s workplace trends of multi-tenant occupancy, cross-organisational communication, activity-based workstations, shared facilities and dynamic office layouts, it’s also one of the smartest buildings in Europe, integrating 'Internet of Things' concepts into the design that allow optimisation of everything from access and indoor climate control, to maintenance and energy supply, as well as the behaviour of users.
The sides of the cube-shaped building measure 42.5 metres and resemble an abstract, modern sculpture from the outside. The building’s appearance changes constantly depending on how the light falls. Architects 3XN have created deliberate geometric transformations that create a prismatic pattern of triangular surface reliefs. Dynamic recesses have been cut into the façade to create terraces for the building’s tenants on the upper floors.
The fully glazed façade is extremely energy efficient due to its osmotic skin, which includes a pioneering application of solar control coatings on the outer skin of the double façade. This, in addition to a suite of technical solutions that include energy capture from heat, allow cube berlin to perform as a highly energy efficient fully glazed building that is pursuing DGNB Gold certification.
For the whole building, ClimaGuard® Premium2 + SunGuard® SN 62/34 + SunGuard® HD Diamond 66 from Guardian Glass were used.
‘’In order to make the building work as a sculpture on the square, we were looking for reflective glass that emphasises the surface while also visually reflecting the surroundings. ‘’
Partner at 3XN
Torben Østergaard, partner at 3XN, the architect on the project comments: “In order to make the building work as a sculpture on the square, we were looking for reflective glass that emphasises the surface while also visually reflecting the surroundings. Our hope is that the design will prompt passers-by to ask ‘What’s actually going on here?’ and maybe even evoke a sense that the building is actually flirting a little bit with you.”
The aesthetic impact is clear, made possible by a carefully balanced combination of glass types. Less apparent is how this double skin ventilated façade is also a perfect example of how architectural glass design can deliver on the structural and energy requirements of today’s ‘intelligent’ commercial builds.
As well as its stunning architecture, cube berlin, a CA Immo project, is committed to environmental sustainability. It offers reduced energy consumption compared to traditional office buildings and the ventilated double-skin glass façade is a crucial factor in this.
Maximising natural daylight for the building’s occupants was also an important consideration. As Torben Østergaard states: “We were aiming at a fully glazed façade, not only to produce the best possible daylight conditions but also to allow for the particular feel of floor-to-ceiling windows that offer great outside views.”
‘’The biggest challenge was the need to combine the design and aesthetic concept of the architects and the technical requirements of the building. We had to identify exactly the right combination of products to use, and this involved a great many tests and calculations, as well as producing many different samples.‘’
Olivier Beier Costa
Guardian Architectural Sales Manager
In addition to coated glass products, the team at Guardian Glass provided technical expertise and commercial support throughout the design phase, drawing on many years of experience and knowledge.
As Olivier Beier Costa, Guardian’s Architectural Sales Manager and who was involved in the project states: “The biggest challenge was the need to combine the design and aesthetic concept of the architects and the technical requirements of the building. We had to identify exactly the right combination of products to use, and this involved a great many tests and calculations, as well as producing many different samples.”
As well as maximising the use of natural daylight, the glass façade not only offers high protection against solar heat gain but provides natural ventilation. To prevent overheating of the façade cavity, both solar-control coatings and solar-absorbing PVB layers have been integrated into the outer glass skin.
Matthias Schmidt, Head of Development at Investor CA Immo states: “We are aiming for DGNB Gold certification on this project. The design of the façade is actually very energy efficient, with a clever technical concept that includes, among other things, regaining energy from heat. An effective energy solution that will negate the common idea glass buildings are severe energy spenders.”
Another major challenge was the unique structural demands on the glass for this project. To solve these, a new structural interlayer compatible with the PVB interlayer needed to be introduced and this combination then approved nationally during the design and construction phase. This new innovation increases edge stability, lowers the risk of delamination and reduces the Yellowness Index.
Torben Østergaard concludes: “Façade designs of this character often meet technical issues that tend to challenge the initial design intent. However, in this case, it’s been a win-win because the technical performance of the façade in terms of energy control goes hand-in-hand with the architectural aspirations.”