A diaphragm-like surface covering

Building envelopes are now considered key elements of architectural design. And although not all projects are able to deliver outstanding aesthetic quality along with adequate comfort and energy efficiency while using standard components and construction solutions, this certainly cannot be said of the new public library in Greve in Chianti.
As the architects from the practice MDU Architetti explain, the architecture in this project explores the relationship between the solidity of the travertine block plinth and the light weight of the superstructure. Enveloped in a clay shell, the upper section captures and reflects light according to the layout of the walls on the various sides of the building and the changing external environmental conditions. The solid travertine plinth encloses the large double-height entrance hall, the information and loans desk and the rooms devoted to cultural and recreational activities. The clay-shelled upper floor where the reading room is located juts out over the areas below and is organised with visually communicating spaces suitable for a range of activities. During the daytime, the diaphragm-like façade cladding allows natural light to diffuse harmoniously into the reading room. The walls, with their fissures, textures and patterns of light and shade, convey a strong sense of materiality. But when the lights come on inside the building in the evening, they reveal a complex pattern of voids and cavities that lend unexpected depth to the surfaces and make the library a unique landmark within the area.
Given its architectural and technological flexibility, Palagio Engineering’s variable screening façade system was chosen for the terracotta shell. Two different facing elements with dedicated technical solutions were adopted.
The solution chosen for the diaphragm façade consists of TerraTube elements (cross-section 150×50 mm) with a characteristic star-shaped opening that allows for inclinations of 45°, 90° and 180° while using the same lateral fixing bracket. In the specific case of the library, a further two inclinations (33° and 16°) were required, which were achieved using specially designed brackets. The solution adopted for the opaque façades consists of TerraTube elements shaped on their reverse side to allow them to be invisibly anchored by means of omega-shaped hooks connected to boxed uprights.
The façade uses preassembled bars fixed at the ends to boxed uprights that in turn are connected to the building’s loadbearing structure only at the top and bottom.
The materials were chosen in accordance with green criteria and consist of clay (due to its natural production processes and raw materials) and aluminium (which is fully recyclable). The proximity of the site to the production facilities has drastically reduced the need for road transport, thereby minimising environmental impact.