Since 2000, a former power station in the London Borough of Southwark has been the home of the Tate Modern Museum. This gallery of modern art now needs an extension and so architects Herzog & de Meuron have designed a new 11-storey tower in the form of a truncated pyramid with a twisted plan form to complement their original conversion work. The facing clay brickwork façade to the extension serves as a bond between old and new. The texture and perforations of the envelope play with the perception of the observer: sometimes the brick wall appears open, at other times closed, permeable or impermeable, depending on viewing angle and time of day. Horizontal window strips, mostly continuing around the corners, plus a few narrow vertical windows break up the clay brickwork and allow selected views of the outside world.
A frame of precast concrete components forms the basic structure for the extension. The aluminium façade elements, supplied by seele and fixed to precast concrete corbels, are fitted in front of the frame. The corbels also support the clay brick outer skin. The unusual geometry of this structure calls for seele’s all-round engineering expertise: the façade rises at five different angles, and twists and turns as well. With numerous different openings, fixed lights and structural glazing units, the result is almost 2300 different façade elements. Owing to the highly complex intersections, 3D design is the only option for the contours of the outer edges. All the window sections comply with the necessary sealing and thermal insulation requirements. And everything is accomplished with minimum space between the precast concrete components, which means minimum erection tolerances.
The sloping glass sliding doors in the entrance zone plus the vertical window strips extending over several floors are among the special constructional features of this project. From the 11th floor, visitors will be able to enjoy spectacular panoramic views across the City of London through the terrace façade supplied by seele.

Hayes Davidson and Herzog & de Meuron
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Hayes Davidson and Herzog & de Meuron Zoom