La queue du lézard - Community centre, games library and public spaces in La Rochelle, N.W. France Urban bonds - The project is located in a district whose urban development, typical of large housing complexes, is based on the planning principles of the 1960s. Based on a free open plan, it takes its coherence from its composition on a strictly right-angled grid. The space freed by the various demolitions made it possible to reorganise the public spaces, to accommodate new buildings and to assert the opening of the old Châteaux d’Eau neighbourhood onto Mireuil. The building fits naturally into this urban layout and is stretched in the form of a long volume of wood. From the viewpoint of form, the idea is to preserve a strictly horizontal building on a sloping site. This asserted horizontality gives coherence and legitimacy
to this new programme in its confrontation with the scale of the site. This urban bonding, which takes places physically within the time required for rebuilding the city within itself, also forms a social bond in people’s minds and mentalities. The choice of generic architecture gives real strength to the scheme and allows it to accommodate the different programmes in a unified, coherent whole. It is the fine quality of the architectonic elements, the use of high-quality materials, and the play with light and sun that make it so varied and interesting. Experimenting with the active strip concept - A concrete “spinal column” contains all vertical circulation routes, sanitary accommodation and building services areas. The roof contains a continuous services plenum covered with metal gratings that also cover the vertical e
nds. The adjacent roofs are planted and not accessible, but they are visible from neighbouring buildings. Glue-laminated timber portal half-frames, placed on a regular 2.70 m grid, form two spacious simple roofed structures – one on each side of this backbone – where all the scheme’s high-quality spaces are located. The envelope consists of a timber framework façade covered with Douglas Pine weatherboards, placed vertically and horizontally in alternation. These elevations appear to be held in place by vertical “props” that dance along the façades. These “props” consist of galvanised steel T-section stanchions, delicately faced with stabilised timber. On the south façade, the “props” are detached from the façade and support brise-soleil sun-breaks. Their positions are calculated to completely stop sunshine in the summer and to allow it freely into the rooms in winter. Integrating environmental design for a Low Consumption Building project - Certain fundamental principles of environmental design were applied: - a “bioclimatic” architectural concept based on compact buildings, ideally oriented in relation to the sun’s path. - a part of the structure is in concrete to give the building the required thermal inertia. There is also a glue-laminated timber structural framework. The external facings are in forested wood, such as pine. - thermal insulation is reinforced to limit heating needs. The choice of external insulation decreases thermal amplitudes between day and night, and between winter and summer. Special attention is paid to the building’s airtightness. Heat losses are limited, particularly by providing air-locks in all cases. - the spaces and openings are designed to limit heat losses and overheating as follows: On the south, large glazed wall openings are protected by canopies (which are adjusted to allow in the winter sun and to completely stop sunshine in the summer) and dense vegetation. On the north, glazed wall openings are reduced. On the east and west façades, the openings are fitted with external fabric blinds. - for summer comfort, the principle of natural ventilation is applied. On façades, users have access to opening parts. - sedum type roof planting increases the retention of rainwater, attenuates thermal shocks, and presents an aesthetically-pleasing “fifth façade” to neighbouring residents. - from the energy viewpoint, the spaces are highly insulated to reduce static heat losses. To counteract dynamic heat losses, the premises are ventilated by high-recovery (80%) double-flow units, with a thermal management system of the Trend type. - the buildings are connected to the existing heating system. Large rooms have floor heating (any overheating due to solar gain or to sudden variations in external temperature is limited by the low emission of the heating floor). - sanitary hot water is heated by hot water heating cylinders and solar panels (except for the games library). - in order to improve the energy balance and reduce internal heat gains, the lighting system makes the best possible use of natural daylighting with the installation of light detectors and the use of LED lighting.