A Second Skin Made From Perforated Sheets

It was a long time since the San Michele oratory in the city of Lonate, in the Lombardy region of Italy, had been used for its original purpose. It was empty for a long time, then the city library took over the empty rooms. More and more smallish container-like building sections for the building technology gradually encroached on the square surrounding the oratory in the historical centre of Lonate. In 2006, the city councillors pulled the plug and commissioned the Milan architecture office DAP with carrying out a general renovation of the oratory. “It quickly become clear that the renovation would necessitate serious interventions in the historical building.

In order to keep these to a minimum, we recommended the construction of a second building at the side of the oratory, in which the toilets, building technology and additional rooms would be accommodated, to the city council, who welcomed this proposal. They also made us responsible for the interior design, which turned out to be a stroke of luck as we could thus adapt the interior design to the characteristics of both buildings.” Elena Sacco and Paolo Danelli came up with some extraordinary ideas for the construction of the new building: “We were faced with the problem of revitalising the original character of the oratory”, explains Elena Sacco. “The basic idea was to find a dialectic of interaction and ideally balance the proportions of both buildings. The width of the new building is thus, for example, exactly half that of the existing building and the slanting roof of the new building starts at the cornice between the 1st and 2nd floor of the oratory. A wood panelled passage in the 1st floor allows for easy access.” The new building was, for this purpose, to receive a uniform surface. “For this reason, we decided to fully cover the new building with perforated sheets”, says the architect. “We used 3 mm thick MEVACO perforated sheets R10 U25.98 with round holes on a square pitch.” Some technical challenges had initially to be mastered here. “Perforated sheets can warp due to the influence of heat and cold. For this reason, we calculated the natural expansion at different temperatures. This led to the decision to use the 3 mm thick perforated sheets. We then mounted a metal frame substructure on the white outer wall so that it was as close as possible to this outer wall. We were then able to mount the perforated sheets almost without visible joints. The perforation itself ensures that the minimal residual joints can no longer be seen.” The MEVACO perforated sheet panelling thus encloses the entire building like a second skin, even the windows and doors were not left out. In contrast, the architects came up with something special for the latter: “We changed the perforated sheets at the windows and door acc. to a previously created design template” states Elena Sacco. We enlarged the holes using dynamic water-jet technology. The abstraction designed by us brings to mind clouds. Overall, we gave a total of 20 perforated sheets an artistic flourish in this way.” Design ideas were, however, not the only reason that the architects used MEVACO perforated sheets. “We always attach great importance to an efficient energy management”, explains Elena Sacco. “In this case, the new building consists – on the one hand – of the cement shell with an insulation layer consisting of wood wool and on the other hand of the light-permeable façade made from MEVACO perforated sheets. For this purpose, there is a ventilation system to protect against dampness under the floor as well as a thermodynamic heating system with air-conditioning. The building is thus perfectly insulated.” It is thus no surprise that the people in Lonate love their renovated library. What is new for them, however, are the architecture fans arriving from around the world to marvel at the twin buildings. The jury of the “Philip Rotthier” architecture prize also valued this architectural gem and awarded this prestigious prize to Elena Sacco and Paolo Danelli in 2011.

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