Extension + refurbishment

  • Building Type : Office building < 28m
  • Construction Year : 1947
  • Delivery year : 2021
  • Address 1 - street : 7 rue Antoine Bourdelle 75015 PARIS, France
  • Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.

  • Net Floor Area : 4 631 m2
  • Construction/refurbishment cost : 6 547 000 €
  • Cost/m2 : 1413.73 €/m2

Proposed by :

  • Primary energy need :
    99.85 kWhep/
    (Calculation method : RT 2012 )
Energy consumption
Economical buildingBuilding
< 50A
51 à 90B
91 à 150C
151 à 230D
231 à 330E
331 à 450F
> 450G
Energy-intensive building

Close to Montparnasse train station, this building was built by the ancestor of the EDF company, the "Compagnie de Distribution d'Electricité Parisienne" (CPDE). It has always been dedicated to the management of Parisian public lighting.
Designed in 1938 by the architect Urbain Cassan, it was originally supposed to be twice as large. Only half of the program was built! Combined with the pre-brutalist architecture of the exposed concrete structure, its accidental asymmetry gives its facades an elegance that is as austere as it is atypical.

The renovation of this office and logistics building in a circular economy includes the creation of an agricultural greenhouse on the roof. The construction cycle allowed the reuse of deposits from the renovation site in the extension project. Thus the exterior joinery making up the existing running strips was reused to form the new openings of the agricultural greenhouse.

Agricultural greenhouse reuse

More broadly, the renovation project involves an impact reduction approach by promoting reuse, the use of recycled, sustainable materials, and refined and transformable furnishing solutions.

If you had to do it again?

In the private market, the logic could lead to involving the company upstream to carry out more "test" removals and validate a reuse process.
The same goes for the technical controller, whose conventional involvement can sometimes lead to impasses during construction. Preliminary tests should be reinforced in the same way.

See more details about this project

Photo credit

Credits: Si Architectes - Damien Boboc & Florian Bosc Malavergne
Except video of the assembly of the greenhouse, credit: Serres Anciennes - Guillaume Durost



    Frederic GALLOO

Construction Manager

    Si Architectes







    Damien BOBOC

    Damien BOBOC

    Thermal consultancy agency


    Arnaud FAVAREL

    Structures calculist

    Atelier MASSE

    Raphaël FABBRI

    Other consultancy agency


    Pascal BACH



    Alain CASULE



    Anthony DECAMPOS



    Philippe HOCHART



    Guillaume DUROST


    Bouygues Energies Services

    Kevin Dy

Contracting method

Macro packages

Energy consumption

  • 99,85 kWhep/
  • 50,00 kWhep/
  • RT 2012

  • 250,70 kWhep/


    • Gas boiler
    • Individual electric boiler
    • No cooling system
    • Double flow heat exchanger
    • Solar photovoltaic
  • 3,08 %
  • The technical terrace located in R+7 has been equipped with a fleet of 45 photovoltaic panels with a total power of 19.84 kWp. The production is distributed in the building and consumed instantaneously.

Smart Building

    The BMS installed in the building contains the following information:
    - Monitoring of electricity consumption by floor ;
    - Monitoring of water consumption by floor ;
    - Weather monitoring ;
    - Monitoring of boiler production ;
    - CTA operating status.

Construction and exploitation costs

  • 6 547 000

Urban environment

In the dense urban environment of the Montparnasse district in Paris, the renovation of the building has restored all its brilliance to the facade, decayed by time, which dialogues again with the other buildings of the 1930s. The agricultural greenhouse installed on the roof is integrated into the shades of gray of traditional zinc roofing with its galvanized steel structure.

Building Environmental Quality

  • works (including waste management)
  • waste management (related to activity)
  • water management
  • energy efficiency
  • renewable energies
  • maintenance
  • building process
  • products and materials

Reuse : same function or different function

    • Outdoor joineries
    • Floorings
    • Suspended ceilings
    • Electricity
    • Plumbing

    Exterior metal joinery:

    • Openable carpentry making up the running strips of the R+2 level - 43m² - 40 units - in-situ

    False ceilings :

    • Slabs reused in-situ - 980m²
    • Reuse slabs - 1000m² - from another company removal site


    • Parquet floors - 150m² - in-situ
    • Carpet - 30m² - company unused stock

    Exterior floors:

    • Protective gravel for technical flat roofs - 7m3 - in-situ


    • PVC tube (EU) - 35ml - company unused stock

    Electricity :

    • Downlight luminaires - 71 units - in-situ
    • LED tiles - 247 units - in-situ
    • Exterior wall lights - 7 units - in-situ
    • Fluorescent tubes - 126 units - POLIX lamps - Maximum Design

Sustainable design

    Steel windows

    The building before renovation included different types of exterior joinery, sometimes transformed without regard to their design or their original materials. The project providing for the thermal standards of the joinery, all the existing windows had to be removed.

    At the R+2 level, a continuous band composed of fixed and opening bays was identified as a deposit from the beginning of the project. Made up of T-shaped or L-shaped steel sections , these elements had the advantage of repeating the same dimensional module . This regularity made it possible to envisage a series reuse taking up all the joinery.

    The project included the landscaping of the roof terrace on the 6th floor. During the preliminary design phases, discussions with the Client led to a proposal to build an agricultural greenhouse incorporating reused carpentry from the existing building.

    The "test" removal operations initiated at the start of the construction site led to the abandonment of the reuse of the fixed parts, which were too fragile. The frames firmly anchored in the rebate in the concrete facades requiring a muscular removal to be extracted invariably emerged deformed from the removal.

    The series of openings could be fully recovered. It was treated in the workshop by the company Serres-Anciennes, in charge of the construction of the agricultural greenhouse. The joinery has been sandblasted, galvanized, new compliant glass has been reassembled, and it has been integrated into the structure of the agricultural greenhouse built on the roof.

    The entire design of the agricultural greenhouse takes into account the recovered windows, both in terms of geometry and in terms of systems. Put back into play in this new work, the windows fulfill their function of ventilation and anchor this new construction in the history of the building.

    Agricultural greenhouse reuse



    The disparate floor coverings in the existing building were subject to local renovations. On the 6th floor, the importance of the renovation called for a complete removal of the floors. A relatively new parquet floor in good condition occupied most of the surface. Despite its average aesthetic appearance and given the objective of circular economy, it was decided to keep it.

    The first removal attempts were inconclusive, the company struggling to remove the blades without damaging them. By insisting, it has redoubled its efforts to determine the right gestures and deposit almost the entire surface of the parquet floor without generating any loss . The slats have been stored on pallets on the same floor as their removal to avoid unnecessary handling.

    All of the recovered slats were thus reinstalled at the end of the work.



    Suspended ceiling and suspended ceiling luminaires

    As part of the renovation work and in particular the installation of ventilation (double-flow CTA), the installation of the ventilation and electrical networks required the removal of the existing false ceilings. The high dismantling and modularity of the constituent elements (slabs and ceiling lights) have allowed significant reuse . Damaged tiles and obsolete electrical equipment have been replaced. However, the company took advantage of a parallel project to provide a second deposit of false ceiling slabs, making it possible to further increase the rate of reuse.

    • Recycled cotton insulation from used clothing - METISSE Le Relais
    • Natural lineoleum floors including fragments of cocoa pods - FORBO Cocoa
    • Recycled waterproofing membrane - DERBIGUM NT
    • Incompressible thermal insulation made of recycled cellular glass - FOAMGLASS
    • POLIX lights - MAXIMUM
    • Mineral-bound resurfacing paint (devoid of petroleum chemistry) - KEIM

Environmental assessment

    Waste : 194 tons of which 94.7 tons were recovered or reused (Tricycle Environnement).

    Asbestos : 30m3 of asbestos waste recycled by inerting (vitrification by Intertam). This is the only way to avoid landfill and to guarantee the safety of the residue. The vitrificate obtained (Cofalit) is used as a road surfacing underlay, but many other uses are being studied.

    Categories Avoided CO2 (kg)  Avoided water consumption (m3) Avoided waste (kg)
    Outdoor facilities 758.87665 7.615624425 1062.454084
    Exterior fittings / Locksmithing - Metalwork 0 0 0
    Carpentry 0 0 0
    Partitions 0 0 0
    Coverage 0 0 0
    Roofing / Exterior fittings 14.322 0.1666455 771.7832388
    Lighting 35654.18594 182.3319846 33899.91834
    Safety lights 0 0 0
    Climatic engineering equipment 0 0 0
    Electrical equipment 0 0 0
    Facades 0 0 0
    False ceilings 9211.653825 94.392628 16385.14013
    False floors 0 0 0
    False ceilings 0 0 0
    Structural work 0 0 0
    Sanitary installations 0 0 0
    Insulation 0 0 0
    Exterior carpentry 5234.175 51.7419 3881.482903
    Interior carpentry 0 0 0
    Furniture 0 0 0
    Paint 0 0 0
    Plumbing 0 0 0
    Floor coverings 990.4555122 26.97398957 605.55344
    Floor and wall coverings 0 0 0
    Wall coverings 0 0 0
    Building security 0 0 0
    Locksmithing - metalwork 0 0 0
    VRD 0 0 0
    TOTAL Avoided CO2 (kg)  Avoided water consumption (m3) Avoided waste (kg)
      51863.66893 363.2227721 56606.33214
      Km in a small car Nb of rectangular bathtubs
    nb of years of household waste of a French person
      414909 2421 113


    Equivalent trajet Paris- Nice 471.0  


    The re-use operation saved the equivalent of 414909 kilometers driven by a small car, or 471 trips from Paris to Nice, 2421 rectangular bathtubs filled with water and 113 years of household waste of a French person.

Reproductibility and Innovation

    The replicability of the operation depends on the commitment of all project stakeholders. This evidence, already underlined in the case of project management in general, is all the more important when a reuse strategy must be put in place.

    In fact, each of the participants must be able to adapt their methods in order to materialize the opportunities for re-employment . Without the will of the contracting authority, the project management can hardly carry out the approach alone. Throughout the project, it is the control office and then the companies who must then commit to adopting an open and proactive approach .

    As part of the renovation of the Bourdelle building, the meeting between the company EVESA, keen to promote a virtuous approach to the circular economy, and the Collectif Si Architectes, project managers who have been experimenting with reuse strategies for several years, made it possible to carry out the project.

    The architects then declined this strategy into different objectives, carried out educational work vis-à-vis the technical stakeholders throughout the project. When technical or administrative blockages were encountered, it was also the architects who sought solutions (laboratory tests, understanding of standards, technical modifications, identification of recycling/reuse channels, etc.).

    The main innovations are not of an architectural or technical nature but relate to the progress of the project. When reuse is practiced on a project, it is necessary to carry out test sites upstream of the site itself. This implies the increased intervention of the control office but also that of a construction company to carry them out. In the private market, this early recourse to a company is easier than in the public market. However, it remains difficult to mobilize a company upstream of the construction site, on small structures, without the assurance that it will obtain the site mission. Control offices are also partners whose involvement must be reconsidered.

    The cleaning works were carried out by the company TRICYCLE Env. which acted as a subcontractor for the general contractor in order to meet market requirements.

    The reused materials followed three different paths depending on their nature:

    • materials that do not require any special treatment before refitting (false ceiling tiles, parquet floors, etc.) were stored on site ;
    • the materials subject to special treatment before refitting (steel windows of the agricultural greenhouse) were treated in the workshops of specialized companies ;
    • materials that cannot be re-used in-situ have been stored by the company responsible for cleaning, which is also responsible for their re-marketing.


    Exterior woodwork:

    • Wooden sash windows - 38 units - to reuse construction specialist



    • Sanitary equipment - 900kg - to Tricycle Environnement reuse platform


    Exterior floors:

    • Gravelled slabs - 18.2t - to Tricycle Environnement recycling platform

Social economy

    • TRICYCLE ENVIRONMENT: 11 employees in professional integration
    • METISSE LE RELAIS: all company profits are reinvested in the creation of sustainable jobs.

Reasons for participating in the competition(s)

The circular economy renovation approach, jointly supported by the Project Owner and the Project Management on the project, experimentally prefigures the future of rehabilitation. It is part of an optimization of resources specific to the site and the building in terms of functionality, equipment and architecture. It organizes the project according to opportunities related to existing spaces, to demolitions. It favors the use of biosourced, recycled or reused materials. It optimizes the processing and recycling of construction site waste.

Building candidate in the category

Bâtiments tertiaires / prix de la rénovation

Bâtiments tertiaires / prix de la rénovation

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 circular economy
 materials and solutions
 tertiary building
 Circular Buildings Trophies 2022

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