High school Colbert de Lorient - Buildings B and C

  • Building Type : School, college, university
  • Construction Year : 2015
  • Delivery year : 2015
  • Address 1 - street : 117 Boulevard Léon Blum 56100 LORIENT, France
  • Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.

  • Net Floor Area : 6 060 m2
  • Construction/refurbishment cost : 2 891 000 €
  • Cost/m2 : 477.06 €/m2
  • Primary energy need :
    74 kWhep/m2.an
    (Calculation method : Other )
Energy consumption
Economical buildingBuilding
< 50A
51 à 90B
91 à 150C
151 à 230D
231 à 330E
331 à 450F
> 450G
Energy-intensive building

Educational buildings dating from 1959, renovated thermally by implementing prefabricated wooden panel frame for external insulation. Insulation, rainscreen, joinery and part of the external coating are assembled before the installation of wooden panel frame. Mechanical ventilation of interiors is installed in parallel.

  • Intervention in an occupied high school. Noisy works concentrated during school holidays.
  • High speed of execution : 6000 m² of floor area renovated in 10 months
  • Air permeability of the building divided by three.
  • Heat demand of the building divided by three.
  • Summer discomfort reduced.
  • Improvement of visual and acoustic comfort.

Sustainable development approach of the project owner

The project owner is Brittany Region, which has set up an Eco-referencial system for schools giving them a general framework of sustainable development. On this particular project, the objectives were:
the reduction of buildings' energy needs (class B and - 40% of primary energy consumption)
indoor air quality (low emission paintings and installation of mechanical ventilation )
reducing the carbon footprint through the use of wood

Architectural description

Monochrome and monolithic treatment of floors in black lacquered siding and recreational playgrounds surface in douglas siding. The use of prefabricated wooden coffers was considered from the competition to address the issue of the occupied site and to incorporate a bio-based material, renewable and carbon sinks. Sun protection is threefold:
solar control glazing 70/40 on classes exposed southeast,
black slatted panel forming external shading with horizontal blades
Clear interior screen blinds for the management of glare

Building users opinion

Satisfaction of the high school teams.

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    Thermal consultancy agency









    02 78 62 28 40

Contracting method

Separate batches

Energy consumption

  • 74,00 kWhep/m2.an
  • 90,00 kWhep/m2.an
  • Other

    Heating: 54 Ventilation: 8 Auxiliary: 1 Lighting: 11

  • 161,00 kWhep/m2.an

Real final energy consumption

    62,00 kWhef/m2.an

Envelope performance

  • 0,89 W.m-2.K-1
  • Intervention only on the facades (excluding roofs). Thickness of the façade : 300 mm. Thermal resistance of insulation: 6.8 m² K / W. U wall = 0.186 W / m²K


  • 1,00


    • Gas boiler
    • Gas boiler
    • No cooling system
    • Single flow
    • No renewable energy systems

Biodiversity approach

    Located in a residential area near the city center of Lorient, the High school is served by 14 different bus lines, urban and suburban. He faces another high school, and is located near a supermarket and a few snack bars.


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    PET fleece with PU coating

    The rain screen is used to achieve the airtightness of the facade.


    1468 ppm

    Sound insulation between rooms enhanced thanks to works.

GHG emissions

  • 13,00 KgCO2/m2/an

Life Cycle Analysis

    Wooden coffers construction (spruce) including Breton woods.

Reasons for participating in the competition(s)

  • ​​Intervention sur un lycée en site occupé. Travaux bruyants concentrés pendant les vacances scolaires.
  • Grande rapidité d'exécution : 6 000 m² de SHON rénovés en 10 mois
  • Division par trois de la perméabilité à l'air du bâtiment.
  • Division par trois des besoins de chaleur du bâtiment.
  • Réduction de l'inconfort estival.
  • Amélioration du confort visuel et du confort acoustique.

Building candidate in the category

Rénovation énergétique

Rénovation énergétique

Green Building Solutions Awards 2015

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    Green Building Solutions Awards 2015