• Building Type : Other building
  • Construction Year : 2020
  • Delivery year : 2021
  • Address 1 - street : 48 rue Pompière 33300 LE BOUSCAT, France
  • Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.

  • Net Floor Area : 2 302 m2
  • Construction/refurbishment cost : 4 100 000 €
  • Number of none : 72 none
  • Cost/m2 : 1781.06 €/m2

Certifications :

  • Primary energy need
    60.8 kWhep/m2.an
    (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

The building is located on the northern part of Square Arnstadt. It is stretched in length and as narrow as possible to give pride of place to the park and the gardens of the structure and to present its smaller sides on the side of the 2 streets. The West zone is more urban and open, with a forecourt to the North. The East zone is more intimate and private, bordered by a pedestrian path on the allotment side. The site is permeable on its east, west and north sides, which turns into a pedestrian path.

The "gateway" ecostructure brings together 5 public premises (ERPs) (Nursery, Early Childhood Centre, Parent-Child Reception Center, Ricochet Social Center and the Municipal Postal Agency) and forges links between inhabitants, age groups, uses, nature and buildings, neighboring EPA... Located on the northern part of Square Arnstadt, it offers great freedom of use through generous open spaces, through and framed views of the park. Architecture creates the conditions for a strong inside-outside relationship, strengthening human-nature ties and environmental awareness.

The spaces are designed from the inside out, with great care given to users. Limited and wide circulation, generous heights and supernumerary exits avoid any feeling of claustrophobia and promote well-being.
The project offers the maximum amount of air and natural light.
The use of dry wood construction and the use of bio-sourced materials lower the carbon footprint. The hemp concrete walls bring inertia, hygrometric comfort, purify the air. The frugal or sober approach offers an eco-responsible building connected to its context and its use, integrating natural and passive inputs (solar heating, inertia, cross ventilation, shade, plantations, natural lighting, etc.). It uses renewable energies (wood boiler, photovoltaic) and aims for positive energy. The building is E+C- of level E2C1.

A BIM approach has been adopted.
La Passerelle is a benevolent building, soft and connected to both nature and the neighborhood. He lets himself be crossed.

Building users opinion

The project owner/main contractor relationship was close and of high quality. The owner gave us full latitude to carry out the project, from the studies to the site. He accompanied us all along, in a relationship of benevolence of trust, which was transcribed towards the companies which in return did quality work in a difficult context of health crisis. The public can feel this atmosphere after the building is completed. Mrs. Lavergne: "This place emanates good vibrations"

If you had to do it again?

A curved hemp concrete wall was planned for the market, which had to have a fireproof report and overlook a room with high humidity: in view of the lack of progress in the report of biosourced materials, this wall was finally made as a wall wooden frame, mineral wool filling and hydro plasterboard. This type of situation is for the moment too complex to deal with it in biosourced materials, because we combine a fire safety ERP requirement, a room with high humidity and a curved wall...

See more details about this project


Photo credit

Jean-Christophe Garcia
Hoerner Ordonneau architectures



    M. Alvarez, Chef du Service Patrimoine et Bureau d'Etudes Services techniques Mairie LE BOUSCAT


Construction Manager



    Eric Fouché


    associate architect


Contracting method

Separate batches

Type of market

Global performance contract

Energy consumption

  • 60,80 kWhep/m2.an
  • 78,10 kWhep/m2.an
  • RT 2012

    see RT study

Real final energy consumption

    62,50 kWhef/m2.an

    78,10 kWhef/m2.an

    2 021

Envelope performance

  • 0,31 W.m-2.K-1
    Q4Pasurf. Target value: 1.7 m3/(h.m²).

    intermediate airtightness tests which were carried out during construction in order to ensure (and correct if necessary) the defects of implementation according to the infiltrations observed.

  • 0,51
  • 1,70
  • Users are demanding monitoring and control of consumption. The GTC put in place responds to this request.

More information

Gain 22.2% (RT -20%) The passive level targeted in design is reached with a Cepproject ≤ -20% of Cepmax.


    • Heat pump
    • Water radiator
    • Low temperature floor heating
    • Wood boiler
    • Solar thermal
    • Wood boiler
    • Reversible heat pump
    • Floor cooling
    • No cooling system
    • Natural ventilation
    • Nocturnal Over ventilation
    • Free-cooling
    • Double flow heat exchanger
    • Solar photovoltaic
    • Wood boiler
    • Heat pump
  • 10,00 %
  • 8.6 kW reversible air/water heat pump

    Wood pellet boiler
    Photovoltaic solar panels


Smart Building


    Implementation of a GTC that regulates energy equipment and in particular the wood boiler / heat pump mix


    • Geotechnical drought (Clay soil shrinkage and swelling)
    • Earthquake
    • Urban heat island

    The building is resilient to global warming, through passive treatment and complemented by mechanical summer thermal systems. The building is frugal, it is designed according to its environment and its orientation and integrates passive winter and summer building solutions: heating and storage of winter solar gains, shade and freshness without summer air conditioning by overventilation, patios and revegetation. Paving and masonry walls, and the implementation of hemp concrete shear walls bring inertia to the building.

    The heat island effect is treated by the strong vegetation of the site in the South, the mineralized forecourt part is located in the North. The masonry walls linked to this square are to the north. To the south, west and east, the facades have a wooden frame and cladding. Light colors make it possible to respect the Albedo. The revegetation extends to the foot of the building to avoid the reverberation of heat on hard ground.

    The building is mostly flexible and light (mostly wood frame and framework, few masonry walls, roof with large non-welded panels). The building can move in the event of shrinkage and swelling of the clays in the ground or in the event of an earthquake. Expansion joints are provided. Seismic studies have been integrated into the structural calculations.

Urban environment

  • 5 950,00 m2
  • 38,70 %
  • 1 694,00
  • The land is located on the northern part of Square Arnstadt, in the municipality of Bouscat.

    Square Arnsadt is bordered to the east by a path serving a large area of allotments and overlooking the old railway line planned to be replaced by an urban park linking Bouscat to Bordeaux at Place Ravezies and line C of the tramway. .

    The project is located as close as possible to the northern limit of the site to preserve as much of the square as possible on the south side, the gardens are placed to the south in continuity with the square and the trees of the square located in the right-of-way of the gardens are preserved.

    The idea is to keep as much afforestation as possible, to complete it following the works and to give the greatest possible freedom of use to the square through generous open spaces, crossing walks and pleasant views for all from the roads, the park or building.

    To the North East of the plot, a "piece of forest" allows the evolution of the site, its pedestrian and visual crossing in the East-West direction and the continuity of the ecosystem of the square in the North-South direction of type green corridor, in connection with the shared gardens and the future park on the railway.

    A recolonization of the land by nature accompanies the project, architecture and landscape are intertwined.

    The square development project retains, reinforces and completes the existing facilities that are well made, in good condition and appreciated by local residents. The latter have proven their attachment to the square by protesting against its amputation, so it seems essential to us to preserve everything that can be preserved: plantations, leveling, paths, pavings, pergolas, pavilions, century-old olive trees, street furniture.


    hemp concrete wall

    Poitou chanvre

    La Vergne, 79500 MELLE / Tel 0549077003


    Hemp concrete shear wall made up of a wooden frame, a hanging support in cannisse on which hemp concrete is projected: biomaterial mulch in hemp shiv + natural hydraulic lime. Hemp lime plasters cover both sides of the wall.

    The solution is appreciated for the warm atmosphere created as well as the hygrothermal and acoustic comfort.

    wood boiler room

    Froling modèle PA Pellet 60.

    entreprise K2 Energie, M Peyron, P 06 24 27 01 78, jerome.peyron[at]k2energies.com


    HVAC, électricité / heating, hot water

    wood boiler 60 kW

    The main heating solution of the ecostructure is the wood boiler room for the best desired carbon footprint.
    In addition, an air/water heat pump is used for mid-season and when there is a high level of occasional demand. The first year, the delicate commissioning required a lot of adjustments. At the end of the heating period, this tended to improve.

    indoor air quality (IAQ)

    Management / Others

    There has been careful selection in the selection of low VOC and formaldehyde materials. A furniture consulting mission made it possible to select virtuous manufacturers and create bespoke wood-based furniture. Air quality measurement tests were carried out on benzene, formaldehyde and CO2 levels.

    mashrabiyas - passive summer cooling


    entreprise JSD, M DIDIER SOULE DUPUY Gérant, d.soule-dupuy[at]jsd-groupe.com


    Structural work / Passive system

    Two BEFUP concrete mashrabiyas located on the north facade complete the natural cooling system of the building in addition to the thermal draft openings located on the roof. Other transom openings or bay windows on multi-orientation and on patios complete the passive summer cooling system.

    Moucharabiehs are well accepted mainly for their aesthetics.

Environmental assessment

    CO2: low carbon footprint (level C1)

    clean site charter with waste sorting

Social economy

    insertion clause planned for 11 lots out of 12, 1925 H in total.

    The town of Le Bouscat is committed to a proactive policy of integrating people in difficulty through work. To do this, they appeal to companies through public procurement. The incumbents carried out an integration action with a public encountering difficulties in accessing employment.

Indoor Air quality

    Specific actions aimed at promoting indoor air quality: hemp concrete walls, careful selection of low-grade finishing materials, selection of virtuous furniture suppliers, production of bespoke wooden furniture, dual-flow ventilation.

    IAQ test results on measured rooms / measured concentration:


    measured concentration of:

    - Benzene = 0.342 (living room 1)

    - Formaldehyde = 11.5 (living room 1)

    - Formaldehyde = 9.00 (dorm 1)

    sans objet

    concentration mesurée de dioxyde de carbone salle de vie 1 = 0, dortoir 1 = 0

    RT 2012 - 20%

    bilan saison de chauffe en cours ( effectué sur 1 an )

    The control method used to verify the acoustic quality of buildings is that defined in standard NF EN ISO 10052.

    Acoustic test results compliant:

    Average reverberation time, in seconds, in octaves centered on 500, 1000 and 2000 Hz

    - Programmatic objective: < or = 0.7 s   (activity room)

    - Measured: 0.7s (activity room)

    La lumière naturelle a été étudiée sur l’ensemble des pièces à occupation prolongée en phases APS et APD par des calculs type FLJ (Facteur Lumière Jour) réalisés avec le logiciel Dialux. Les FLJ atteints varient entre 1,5 et 4% selon les pièces.

Reasons for participating in the competition(s)

Le bâtiment est construit sur le principe de la sobriété heureuse.

L'orientation détermine les modes constructifs et solutions de façade. Le bâtiment est E+C- de niveau E2 et C1. Le bois est présent en ossature, bardage, menuiserie et mobilier. Une chaufferie bois par pellets a été créée. 

Le bâtiment intègre une forte réflexion de thermique d'été et de qualité de l'air avec notamment des murs de refend en béton de chanvre, régulateurs d'hygrométrie, apporteurs d'inertie l'été et absorbants de l'air intérieur pollué.

De larges avant-toits, la création de patios d'ombrage et fraîcheur, des pluri-orientations, et enfin une forte végétalisation du site et des surfaces, traitent l'effet îlot de chaleur et permettent de rafraîchir le bâtiment. De grands ouvrants en façade et à soufflet en façades opposées permettent de surventiler. Des zones tampon thermique en combles et façade Nord tempèrent le bâtiment hiver et été.

Le bâtiment est conforme à la RT 2012 - 20%.

crèche labellisée Ecolo crèche® 
HQE sans certification, qualité de l'air
E+C- de niveau E2C1 sans certification

conception BIM de niveau 2

Building candidate in the category

Users’ Choice

Users’ Choice

Green Solutions Awards 2022-2023
 building materials and solutions hemp biosourced wood energy renewable energies BIM health and comfort greening Resilient Buildings Awards 2022

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presidente de la SAS d'architecture

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