Coral House | group8

The Coral house was designed by group8, located in the Chandieu area, formed by a large urban block surrounded by Rue Giuseppe-Motta, Grand-Pré, and Chandieu. Coral House new housing estate takes part of the regeneration of a former industrial site and completes, together with the Bamboo Residence, a large city block. At the intersection of the avenue and the Chandieu road, a public square supplemented by a fountain and a sculpture will be built in collaboration between the artiste Fabric Gygi and the architectural office ADR.

The construction aims to high-quality standards in terms of space and equipment, as well as construction materials and coating. It also seeks the MINERGIE label, by using optimum insulation for the exterior envelope, and highly efficient technical installations (heating is provided by geothermal heat pumps; double flux air system is distributed through the ceiling – ERV). The use of a high energy standard allowed users to obtain 10% additional net surface, compared to what was requested by the neighborhood plan.

The site is accessible by the main road Grand-Pré, this avenue lined with trees, cuts straight through the building block. The future underground parking will be accessible by the entrance of the adjacent building, the Azure center, located on the Grand-Pré road. The building consists of 6 floors, including a double attic (duplex apartments) and a single basement level. The coral house offers 58 housing units, from 4 to 6 room flats (kitchen counted as a room). The ground floor and the first floor are dedicated to commercial activities.

The façade of Coral House on the road front is entirely glazed, exposing the living rooms to the outside giving the impression that the building has been cut or like a section in a dollhouse. The clients specifically asked for a building without balconies, the most suited solution capable to give an impression of the exterior was to have sizable sliding windows offering the possibility to open large sections of the façade.

In the courtyard, each room is indicated by a window perforated in a roughcast wall with exterior insulation. The internal organization of the flats has been developed as the typological system, which puts the hall in the center of the plan, allowing it to distribute all the rooms. The volume of the attic is designed as an object on a pedestal, its aluminum materialization tends to blend in with the sky.

The structural system was sized not only to ensure the stability of the building – including all seismic measurements- but also to ensure a greater sound insulation between apartments but also between the apartments and the common areas. Therefore all bearing walls and slabs generally have a greater thickness than needed for regular stability requirements of the buildings.

All thermal insulation in the facades and roof has been sized to meet the MINERGIE label values, with a clear aim to reduce energy consumption and lower costs for consumers. All windows in the courtyard were designed as breathable windows, meaning: coated aluminum frames with thermal breaks, last generation double glazing, with an additional third glass placed on the exterior in order to provide a ventilated space with a motorized window shade.

The production of the heating and hot water is produced by heat pumps supplied by geothermal boreholes. The apartment heating is a low-temperature floor heating. The coils embedded in the concrete subflooring are fed by a dispenser located in the lobby, which modulates the temperature in each room based on their exposure or their size. In summer, the same network of coils can be supplied with cold water for cooling of the premises.

The ventilation is a type of double flow system, fresh air (filtered, dusted, moisturized if necessary, heated) is prepared in the central and then fed into each room through a system in the ceiling located above the sanitary and hall. Meanwhile, stale air, taken through the sanitary, is returned to central, where its heat is recovered by a heat exchanger, before being discharged. This way, the air quality inside the housing is guaranteed at any time, without obligation to open the windows, and energy loss by ventilation is minimized.

Project Info:
Architects: group8
Location: Rue du Grand-Pré, 1202 Geneva, Switzerland
Project Management: PBM Planungs und Baumanagement AG
Civil Engineer: Walt+Galmarini AG, Perreten & Milleret
M&E Engineer: SB Technique
Electricity Engineer: MAB-Ingénierie SA
Building Engineer: Physics Basler & Hoff mann Holding AG
Sanitary Engineer: Mike Humbert ingénieur conseil
Photographs: Régis Golay, FEDERAL Studio
Project Name: Coral House