- Building Type : School, college, university
- Construction Year : 1968
- Delivery year : 2019
- Address 1 - street : Chemin de la Vallée, 4 4000 LIèGE, Belgique
- Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.
- Net Floor Area : 9 000 m2
- Construction/refurbishment cost : 5 360 500 €
- Cost/m2 : 595.61 €/m2
Primary energy need :
(Calculation method : Other )
The case study concerns the energy renovation of the Institute of Botany of ULiège (Building B22). This building was designed in 1968, according to plans by Roger Bastin. It is an important witness of modernist architecture in Belgium and is listed in the Inventory of Walloon Cultural Real Estate Heritage.
After 50 years of life without major renovation, this building has been the subject of an energy renovation project aimed at ensuring its durability for decades to come and at significantly reducing its energy consumption: -75% reduction in heating consumption and - 21% of electricity consumption (excluding scientific processes). A circular approach, particularly around the issue of reuse, is central to the entire project process. In addition to the installation of reused wood cladding (2,600m²), various construction elements were dismantled, inventoried, cleaned and reused in the renovation project.
This project is part of the sustainable development policy of the University of Liège. It was carried out between 2015 and 2019, as part of the eeef energy renovation program which enabled ULiège to finance studies aimed at renovating 8 of these buildings, all dating from the 1960s, as well as the public lighting network of the campus. The work, financed by the University's own funds, is now all finished.
Photos, project presentation document, summary of costs and energy savings: https://dox.uliege.be/index.php/s/tRriniDv3bGsDsF .
Building users opinion
User feedback is positive. Winter cold problems are solved. The heaters hardly work anymore and the comfort of the building is improved.
The construction phase had been more complex, because the building remained occupied during the works (research activities, teaching, material impossibility of emptying the building for 1.5 years), which involved a lot of nuisances (cold during the opening of facades, noise, dust).
If you had to do it again?
The project went very well overall, thanks in particular to the good collaboration of all the project stakeholders. If it were to be redone, two points would need to be improved: (1) finding buffer rooms in another building to spare the occupants during the work and (2) carrying out (which the program deadlines did not always allow) an overall renovation / upgrading of the building (partial lighting, refreshing of interior finishes, etc.).
See more details about this projecthttps://opalis.eu/fr/projets/linstitut-de-botanique-de-lulg
Samuel Defourny for photos B22 (1), B22 (2) and B22 (3); ULiège for others
Construction companyLes Entreprises Gilles MOURY sa Gwadamère GERARD GSM: 0491/71.27.67 ggerard[a]moury-construct.be General construction company in charge of carrying out the works
Thermal consultancy agencyTEEN CONSULTING Vincent KOWALCZYK Energetic audience
- 357,00 kWhep/m2.an
Real final energy consumption
- Combined Heat and Power
- Individual electric boiler
- No cooling system
- Nocturnal Over ventilation
- Double flow heat exchanger
- Solar photovoltaic
- Biomass boiler
- 39,00 KgCO2/m2/an
- 53,00 KgCO2 /m2
- 50,00 an(s)
Life Cycle Analysis
- reused wood cladding
- mineral wool
- reuse of original materials
Indoor Air quality
Health & Comfort
Reused wood (facade cladding)
Gros œuvre / Structure, maçonnerie, façade
Reused wood cladding - planks from old barns in Eastern Europe.
This type of project, on a large scale moreover, leads to fears as to the durability of the materials, their reception by the users, the ten-year guarantees, the conditions (temporal and financial) of implementation... The company, for lack of knowledge of this subject and familiarity with reuse practices, initially showed a form of reluctance (without however directly opposing the proposal). Here again, it is up to the author of the project to provide the arguments as to the technical feasibility of the file and its aesthetic qualities. A sustained and in-depth study of the entire project upstream obviously puts the company in the best possible position. Most of the questions raised can thus be anticipated. The technical qualities of the managers and their experience are also crucial in the constructive dialogue that ensues.
60/60 floor tiles and metal roof cladding
Matériaux existants sur site
Second œuvre / Revêtements de sol
Very good acceptance of the solution.
AZOBE decking boards
Realization of an outdoor terrace in reused azobe boards (former Dutch docks).
Very good, but substantial work to level the terrace (planks of different thicknesses) by the company.
Construction and exploitation costs
- 68 000,00 €
- 56 000 €
- 5 426 000 €
- 30 000 €
Building B22 is located on the Sart Tilman campus of ULiège, of which more than 250 hectares are classified as a nature reserve. This campus was developed in the 1960s in order to preserve the forest massif and the natural area from real estate pressure and prevent the development of housing estates of 4 facade houses. A coordinating plan was produced by Claude Strebelle and still serves as guidelines for the development of the campus.
The campus covers nearly 760 hectares, a third of which is classified as a nature reserve.
parking for employees in front of the building, the project also made it possible to create a covered bicycle shelter with 20 spaces
Reuse : same function or different function
- Barnwood type cladding from Eastern Europe, collected and distributed in Austria, resold in Belgium (Biemar Bois), implemented by the company Moury (subcontractor GROVEN Portal) for the production of new cladding of facade of ( 2,600 m² );
- Azobé planks from former Dutch port docks, resold in Belgium (Biemar wood) for the construction of an outdoor terrace ( 140m² );
- Metal roof cladding ( 400 m² );
- 60/60 concrete slabs in floor layout ( 120 m² );
- Recommissioning of an old ventilation unit shut down 20 years earlier: 50,000 m³ ventilation network restored from old ductwork.
- Siding installed vertically ensures that the material holds up well over time (faster rinsing of rainwater).
- The cladding interspersed with horizontal slats arranged at several spacings gives more regularity to the whole and avoids having to assemble heterogeneous boards end to end – which facilitates the work of implementation.
- By varying the dimension of the center distances, it was also possible to work with more heterogeneous elements, and in particular production offcuts, which were thus able to find a place in the composition.
- The horizontal lines that emerge from the composition also recall the traces of the formwork levels of the initial concrete.
|Categories||Avoided CO2 (kg)||Avoided water consumption (m3)||Avoided waste (kg)|
|Exterior fittings / Locksmithing - Metalwork||0||0||0|
|Roofing / Exterior fittings||0||0||0|
|Climatic engineering equipment||0||0||0|
|Floor and wall coverings||0||0||0|
|Locksmithing - metalwork||714,070531||8,850474704||470,6229617|
|TOTAL||Avoided CO2 (kg)||Avoided water consumption (m3)||Avoided waste (kg)|
|Km in a small car||Nb of rectangular bathtubs||nb of years of household waste of a French person|
|Equivalent trip Paris- Nice||395,0|
The reuse operation saved the equivalent of 347633 kilometers traveled by a small car, or 395 trips from Paris to Nice, 59222 rectangular bathtubs filled with water and 82 years of household waste of a French person.
Reproductibility and Innovation
- The texture : the texture of reused wood, heavily veined, is the opposite imprint of the texture of the original concrete. An analogy is created between the initial texture (still present inside the building) and the new facade cladding.
- Lack of control : at the time of construction of the building, the aesthetic quality of the concrete was relatively random (traces of poor workmanship, differences in color, etc.). This diversity, the result of on-site production, disappeared when the building was painted in the early 2000s; while it contributes, as much as the texture, to the brutalist character of the building. The reused wood thus makes it possible to reinject into the building a material of which the architect does not control all the aesthetic aspects.
- The age value (according to the Austrian art historian Alois Riegl): this 50-year-old building has a patina, the mark of the passage of time. The choice of a reusable material, itself patinated, furrowed, attacked… makes it possible to avoid the effect of a facelift and to preserve the building's dignity of its age.
- Sustainability : the objective is to complement energy sustainability (reduction of consumption and greenhouse gas emissions) with a deeper reflection on the durability of materials, with the intention of avoiding the overconsumption of resources and their looting.
- 520 000 €
- 10 %
Reasons for participating in the competition(s)
The energy renovation operation of the Botanical Institute seems to us to be exemplary for its integrated approach to sustainability and circularity at several levels:
- The renovation and reinvestment in the existing built stock, instead of new construction on a virgin site, is part of a strong approach to sustainable development and the reuse of existing infrastructure. The scientific literature has also highlighted the environmental benefit of major renovation compared to demolition/reconstruction operations.
- The project combines high energy and environmental performance with respect for the heritage character of the building, witness to the modernist architecture of the 1960s. of Liege.
- Energy performance (confirmed by measurement campaigns) has been greatly improved: -75% of heating consumption, -21% of electricity consumption (excluding scientific processes).
- Reuse and reuse have been at the heart of the approach since its conception (in particular life cycle analysis) which has made it possible to implement 2,600m² of reused wood cladding but also to restore and reuse, in situ or on other university sites, some original materials. The technical networks (ventilation) were also partially reused.
- The project is part of the broader framework of an energy renovation program for ULiège's infrastructures. On the strength of this experience, a second wave of energy renovation will begin (as part of the recovery plan of the Wallonia-Brussels Federation).
- The project materialized thanks to the integration, communication, collaboration and mobilization of all the players (architects, client, companies, user representatives).
- The work was carried out in an occupied building.
- Budgets and schedules were perfectly respected thanks to precise and rigorous technical and administrative management.