1+1=1 | Rue Royale Architectes

1+1=1, the possible equation. 1+1=1 belongs to a new generation of housing schemes. Located in the high-profile and highly-publicized district of La Confluence in Lyon, it combines strong architectural, social and environmental ambitions with the unique way in which the project was set up and organized, based on an aim of social mix. As an extension of the “ABC” blocks of the first phase, north of the dock, at the corner of Cours Bayard and Rue Paul Scherrer, it writes the sequel to the story of the La Confluence mixed development area. In the form of a right-angled building, without concession or aggressiveness, it is unique in that it harmoniously combines two programmes, respectively consisting of rented and owner-occupied social housing, as well as two clients: SCIC Habitat Rhône-Alpes and Rhône Saône Habitat. - The right angle, a strong urban figure. - Play of materials. - Entrance and circulation, two specific features of apartment buildings. - Social housing, a subject of continual exploration for the firm. - Sustainable development. The L-shaped building, a radical urban figure. With two housing programmes and two project owners, the basic idea of the scheme was to propose one single L-shaped building capable of creating a strong architectural and urban figure. The architects devised a right angle composed of two blocks that respond to each other in an overall composition. Two principles were indispensable for the success of this concept: to use two completely different materials to avoid creating a heavy, massive design scheme and especially to not give the corner any specific treatment, so that its force remains intact. This massing, simpler than the first “ABC” blocks marks the northern boundary of the ZAC (mixed development area) and provides the compact form needed for high energy efficiency and the required economical use of resources. Play of materials. This rationale of plan and volume is enhanced by the choice of two materials that respond mutually. The materials create a contrast that enables each project owner to identify with their own building, even if the reality is not quite faithful to what is visible and the interfaces are finer and more numerous in the mix of the two programmes. As is often the case with its schemes, the rue royale firm plays with materials and their skin effects, in a subtle composition and with refined construction, sometimes going as far as using them in an unconventional way. The north facade, which corresponds to RSH’s subsidized owner-occupied housing, uses mastic-coloured Eternit© cement fibre panels assembled with an ingenious changing pattern. Cutting of the panels was optimised to create a rhythmic pattern that varies from east to west. Windows and panels firstly follow a very tight, very vertical composition and then start a more flexible, more irregular movement as far as the west corner. Metal prefabricated frames, protruding 10 cm outside the facade plane, enhance this effect by creating graphic shadows. Coloured films applied to the window breasts create a more dynamic second rhythm. Sheltered loggias are provided on the south facade. The concrete structural columns supporting them are placed slightly out of line with each other, to avoid an excessively massive design. The perforated metal sheet guard rails create moiré interference patterns, act as visual filters and avoid unwanted invasion by materials such as cane reed, to protect privacy on the balconies. On the west, the material of the north facade turns round the corner, forming an L-shape, framing an outer skin of Douglas fir. Wood offers a changing material, more raw and natural, built according to the patterns of cladding boards, creating transparency and opposing the sculptural appearance of the north facade. Entrance and circulation, two specific features of apartment buildings. To obey the balance between programme and concept, RSH’s subsidized owner-occupied homes are located on Cours Bayard, with three apartments on every floor level, benefiting from double aspects, with balconies on the south and west. With this arrangement, SCIC Habitat’s rented housing units face both east and west, with a view of the sunset and a view of Fourvière hill. The space that serves them is deliberately made abnormally large, to provide an extremely generous space between the street and the privacy of the home. Creating social bonds, it avoids the boring corridor and uses the famous “Cour des Voraces” as its architectural reference . Four apartments on each floor level are served by walkways and access balconies arranged around a central void protected by a glazed roof panel. The unenclosed stairs run along a facade that is half-open to the exterior, with a 50/50% solid/void ratio, and in an irregular composition based on the window proportions. The choice of the turquoise blue colour in this large central void differentiates it and makes it identifiable. 1 The Cour des Voraces is the courtyard of a building in Lyon that is known for its six-storey monumental facade stairs with open-air flights. Located on the slopes of the Croix Rousse area, it is a symbol of Lyon, an impressive “traboule” through building that takes its name from a group of “canuts” (silk workers) who are famous for their uprisings (1848-1849). The accent placed on this shared space for rented housing has an equivalent in the treatment of the entrance to the RSH housing. It is recessed, visible without being monumental, and it is in quite joyful fuchsine pink. A set of vertical security bars visually isolates the services plant rooms. Social housing, a subject of continual exploration for the firm. The architects of the rue royale firm have a committed philosophy. Most of their work concerns social facilities and subsidised housing. Building on their experience, they are used to social housing’s subtle brain-teaser game of juggling between floor area, price and quality of spaces. A continual subject of experimentation, it is one of the most complicated exercises in architecture and represents 80% of the city. The 1+1=1 scheme responds to some of the firm’s rules with rigour and generosity: firstly, the daytime / night-time separation in apartments with one or more bedrooms and, in the daytime part, the opening of the entrance hall, kitchen and living room space s. The apartments all have double aspects and comfortable balconies. As much daylighing as possible is sought, including in the wet rooms. The aspect of the rooms is determined according to basic bioclimatic principles as well as views and quietness. The kitchens, bathrooms, service rooms and night-time spaces are placed on the north in large apartments of the RSH programme, leaving the living room, considered as the main habitable room, with the balconies, the south and west aspects, and the views of the garden or the Monts du Lyonnais hills. In the SCIC programme, most of the kitchens receive daylight from the central void and are turned towards it, so that the bedrooms and the living room are on the facades that have balconies. The entrance hall, kitchen and living room areas are opened with the aim of expanding space. Each area is perceived as demarcated while preserving the perception of the overall volume. A section of wall conceals the electrical household appliances. Sustainable development. To comply with environmental performance requirements, the architects, working in close cooperation with the Etamine environmental engineering firm, based themselves on simple, rigorous principles. Firstly, they chose a very compact building, which significantly reduces heat losses and costs. The bioclimatic approach optimises aspects, giving precedence to the south and the east sides, looking onto the garden. Where possible, the double aspect of the apartments contributes to summer comfort by providing natural ventilation. The double internal and external insulation creates optimal insulation performance. The necessary thermal inertia is provided by the mass of the internal load-bearing partitions and of the solid floor slabs. From the viewpoint of specific technical facilities, one may mention the installation of 90 m2 of solar panels on the roof to heat sanitary hot water. Space heating is provided by a two-way flow system with preheating of air by a gas boiler that can also act as a back-up for heating sanitary hot water. Considering the low heating needs, small additional electric radiators are provided for occasional use during cold peaks. The architects’ work was complemented by thinking on the long-term future of the 1+1=1 scheme, in order to consider its development and its possible transformation. The scheme won the 2008 Prébat (Programme de Recherche et d'Expérimentations sur l'Energie dans le Bâtiment) award for the part consisting of unsubsidised owner-occupied housing. Project data : Clients : Scic Habitat Rhône-Alpes & Rhône Saône Habitat Architect : rue royale architectes Developer Contractor : SPLA Lyon Confluence QEB AMO : Tribu Building environmental quality engineers : Etamine Construction economist , Building services, Scheduling, Supervision & Coordination : MG Plus Structures : Cerbéton Quality control and SPS : BTP Consultant Photograph : Studio Erick Saillet / erick.saillet1@ : Peter McCavana Programme : 56 logements sociaux (30 logements locatifs sociaux pour Scic Habitat Rhône Alpes 26 logements en accession sociale pour Rhône Saône Habitat 2 niveaux de parking en sous-sol (59pl) Total area : 5 166 m2 (2 702 m2 SHRA / 2 464 m2 RSH) Net usable floor areas : 4 106 m2 (2 166 m2 SHRA / 1940 m2 RSH) Cost : 4 969 000 €HT soit 1 210 €HT / m2 SH (2 507 000 €HT SHRA / 2 429 000 €HT RSH) (1 157 €HT / m2 SH SHRA ; 1 269 €HT / m2 SH RSH) Performances : Label BBC / Lauréat Prébat 2008 pour la partie accession Specifications : Structure et façades béton. Bâtiments fondés sur radier avec inclusions rigides. Double isolation intérieure et extérieure. Vétures panneaux fibrociments Eternit et Pin Douglas. Eau Chaude Sanitaire par panneaux solaires. Double Flux avec préchauffage de l’air. Chauffage électrique. Eclairage naturel des parties communes. Toiture végétalisée sur bâtiment SHRA.