Sustainable construction

Energy performance

Associating the construction of positive-energy buildings and the renovation of existing buildings


Anticipating the French heating regulation “RT 2020” which, after 2020, provides for the implementing of “Bâtiments à Energie POSitive” or “BEPOS” (Positive Energy Buildings), EIFFAGE has been developing its own positive energy concept applied to both new construction and renovation.


Priority is given to reducing the energy needs of the building through its bioclimatic design, the compactness and inertia of its shape, the treatment of its envelope and its façades. The residual energy needs are then handled with, as a function of the potential of the territory, exclusive use of local renewable energies.


In a rationale of analysis of the life cycle of the building, the "embodied energy" corresponding to the energy use and greenhouse gas generation during the construction phase is taken into account in the choices of construction processes and materials.


Each building is characterized by a specific set of uses and an architectural shape which affect its energy and economic performance. The Phosphore teams therefore developed two BEPOS approaches on buildings that are different in all ways except that they are both old and remarkable.


The "high-tech" approach is applied to The Maison du Bâtiment, a very tall building of the 1960’s, requiring a particularly substantial technological exterior treatment and consequently a new sophisticated programming.




Maison du Bâtiment Strasbourg, approche hightech du bâtiment à énergie positive



The Phosphore teams want to prolong the working life of the building while going beyond the BEPOS standards planned for 2020 for new construction. This ambitious choice will amortize the embodied energy expended for its construction. All of the energy needs specifically for the operation of the Maison du Bâtiment, limited to a minimum, are covered by the production of local renewable forms of energy.


In terms of uses, the south and west façades, which have good exposure, will welcome service sector and sports activities, public services and restaurants, and housing units. An upscale hotel occupies the northeast part.



The "low-tech" approach is applied to the so-called "Restos du Cœur" building, a compact construction representative of the industrial architecture of the early 20th century, requiring more modest technology and adapted to the maintaining of its social objective.



Le bâtiment des Restos du Coeur à Strasbourg, approche lowtech du bâtiment à énergie positive. EIFFAGE - Phosphore III



By conserving the historical façades of this industrial building, EIFFAGE is once again carrying out energy rehabilitation, but now by integrating different architectural and use constraints.


Alongside the initial function of social solidarity there are programs for housing, public services and service sector activities housed within an extension made with a mixed concrete/wood structure.


Thermal solar and photovoltaic panels are installed on the inclining roofs facing south. Panes of photovoltaic glass are arranged on the south and west façades and supplement the residual needs of the building.


Wood, preferred for structures and façades, reduces the environmental footprint of the building.

Positive energy buildings