Carre Seine by PietriArchitectes.

Description of project by PietryArchitectes

In the space of fifteen years, Issy-les-Moulineaux has become a leader in the field of HEQ in the inner suburbs of Western Paris.

This distinction strengthens its status as a new economic platform home to the headquarters of major French and international companies. At the same time, new residential neighbourhoods have sprung up promoting diversity, today’s urban “religion”. Even more demanding than the charter required for low energy buildings (BBC), Isséo+ has been drawn up in a participatory manner.

This development is located in the mixed development zone (ZAC) stretching from the banks of the Seine in Issy-les-Moulineaux opposite Île Saint Germain up to the Jacques Henri Lartigue tramway station on the T2 line. The operation is part of the Val de Seine masterplan. This site is served by RER C train line and several underground lines (8/9/10/12). However, the T2 and RER C lines create a significant urban barrier which isolates this site from the rest of the city. Hence, the development on this islet of landscaped, pedestrian, and cycle areas (ground floor retail premises) running perpendicular to the Seine will open up this part of the city, where non-motorised transport will be a credible alternative to car travel, including for local journeys.

Isséo+ label, Carré en Seine demonstrates the use of unusual housing techniques to meet demanding HEQ and thermal regulation specifications (RT 2005/65kw/hr/m²/yr). Small in size, the distinctive character of these homes lies in their high environmental quality and the innovative use of outdoor spaces, which are detached from the façade to form zinc “boxes” oriented towards the views and sunlight.

This urban construction is made up of three buildings comprised of many distinct architectural elements. First, there are two buildings comprising 69 dwellings (BBC, NF, and HEQ). Secondly, there is a hotel residence with 175 rooms, the technical facilities of which are located in a dark brown brick tower on the 10th floor, a real landmark on Rue du Passeur de Boulogne.

Surrounding a shared patio, the three buildings provide soft stories and views of the Seine. Density is controlled by breathing spaces, connected, on the Seine side, via metal walkways. The concrete of the north façade of the tourist residence overlooking the Quai de la Bataille de Stalingrad has received a specific moulding treatment (“ bamboo” model).

It is the fruit of a competition launched in 2009. Out of the three competing architectural firms, Jean-Baptiste Pietri was chosen along with the landscape engineering firm Atelier Jours. During the competition stage, the Franck Boutté engineering firm was added to this team. The major challenge of this hyper-rational programme was to control density: those involved were asked, in effect, to develop 11,000m²on a plot of only 2500m².

From the beginning, Eiffage worked with the architect Jean-Baptiste Pietri and the engineering firm Franck Boutté to implement two proven and marketable innovative technologies. They threw their weight into the balance of the programme created and into acquiring the Isséo+ label:

The use of an insulated cavity wall

Built-in insulation is guaranteed by the thickness (35cm) of the ready-built module to be fitted and given electricity cables. It is made up of several layers: 12cm of polyurethane, 7cm of white cement concrete external skin (no rendering), and 4cm of concrete for the inside wall. Only the middle, weight-bearing section, measuring 12cm in thickness, is filled with concrete poured on-site. Lastly, each module is fixed with composite resin to ensure the absence of any thermal breaks.

The sustainability of the structure is ensured through the use of concrete. This device is better adapted to the typology of the envelope calculated to meet the required density; this industrial cavity wall is suitable for cutting approved by the contractor.

Benefits of the loggias

The loggias act as conceptual grafts and are part of the second most distinctive characteristic of this programme. Eiffage and the architect Jean-Baptiste Pietri thought them up to meet their desire to offer a “benefit” in the urban environment in which the property is located. They also serve as a climatic buffer (solar gain protection in summer) and may be completely closed according to the wishes of the inhabitant, who can transform them into a “mid-season” room.

These loggias have been designed in an outer metal structure in the style of a large scaffold attached to the façade. This process prevents thermal breaks and provides better disabled access.

In addition to the comfort provided by these loggias -acoustic buffer and windbreak- these added spaces are staggered according to their orientation so as to better capture the light and sun.