New SPG Headquarters in Geneva designed by Giovanni Vaccarini

Description of the project by GIOVANNI VACCARINI ARCHITETTI

The project for the new Headquarters of SPG in Geneva starts with the adaptive reuse of a pre-existing building to which we added extra floors and a new facade. The quality of the workspaces was the central theme for us, which led us to completely redesign the exterior facade of the building. The new envelope consists of a first layer of triple-pane glass. A fourth glass layer contains the micro-punctured blinds to adjust natural lighting; screen-printed glass brise-soleil screens are anchored to the outside. The glass fins, placed perpendicular to the facade, come in three dimensions (20, 40 and 60 cm) and are spaced apart with varying distances, defining the entire facade. This whole system occupies a total thickness comprised between 40 and 80 cm. A “thick surface” that, starting from the design of the exterior envelope of the building, becomes the very body of architecture. A geometric system that, starting from the design of the glass fins, reverberates onto the interiors, the functional layout, the geometric pattern of the flooring made of local stone from Vals with stainless steel inserts.

First essential requirements for the project have been to guarantee a good level of protection from the sunlight while, at the same time, not to limit the view from the inside outwards. Our solution was about implementing a stratified glass panel, finding a balance between the shading capacity of screen printing and their permeability to vision. The glass fins shape a “nebulous” envelope, that marks out multiple reflections and transparencies. During nighttime the glass fins are enlightened by white leds and transform the building into a kind of urban lamp.

I think the result is extraordinary, in the literal sense of the term (out of ordinary). A simple system that, when reiterated, produces a complex multiplication of visions, both on the inside and on the outside of the building; a kinetic architecture.

The double facade 
 
The structure of SPG office complex consists primarily of a skeleton of pillars and reinforced concrete slabs, on which they are hung on the cells that make up the prefabricated curtain wall. The individual cells make up the double-skin facade, a system that allows, on one hand, to naturally ventilate the building´s envelope, on the other, it is a shield against solar radiation. The ventilation system has been combined with an internal system of forced ventilation, still reducing the building’s energy consumption when compared with a traditional facade. 
 
Curtain wall and flexibility 
 
The division of the facade in prefabricated modules, aligned with each plane along a horizontal band, provides flexibility in the arrangement of internal partitions, making it possible to place a wall every 1.5 meters. The double façade is composed of prefabricated cells, the standard modules are 1.5 wide and 4 meters high. These are dry hooked to the reinforced concrete slabs through hooks, vertically and horizontally, and are bound together by a male-female system. Each module has a double skin, one internal and one external, made of glass mounted on aluminium. The inner layer consists of a traditional type frame windows providing high- performance thermal and acoustic insulation. The outer layer instead, at a distance of 30 cm from the front line, consists of a single tempered glass, screen-printed on the inside, and glued with a structural silicone to the frames (partly fixed and partly vertically rotating). Finally, the glass panels, thanks to the dotted serigraphy printing that covers 80% of the surface, act as a brise soleil, ensuring transparency and visibility. United in groups of nine, the mobile and electronically controlled panels, can be rotate on their vertical axis by a central hinge thanks the engine in the intrados of the prefabricated cell. Their movement is controlled and regulated by light sensors positioned on the façade. The control system of engines is centralized (BUS).
 
New type of clients and flexibility 
 
The ventilation system of the façade offers the possibility to move the ventilation system to the outer perimeter of the building, and therefore offers the opportunity to clear the ceilings of each floor from the bulk of large size pipes and false ceilings: a very popular design and energetic principle in Germany that has not yet been consolidated in our country. In fact, even the air conditioning system of the MAC 567 combine the natural air to forced air conditioning systems positioning them in the ceiling. This kind of choice is explained in the needs of interior space distribution flexibility of an office building designed for future leasing to a services company. The tenants company needs to come into play only when the building is almost finished. The spread of a new type of client, the one of big companies of development, which builds large buildings, creates a distance between the actors of the design process - construction (committee and designer) and end-users, with their specific distribution needs. This fact necessarily affects the design and technological choices of a building.