Circular Retrofit Lab




1. The students' houses in orginal state.

2. The stripped structure


4. Addition of wooden battens for the façade finishing.

5. Attaching the façade finishing.


3. The addition of the modular façade panels.


6. The Circular Retrofot Lab in final construction stage.

The progress of the construction of the Circular Retrofit Lab. © VUB Architectural Engineering


Initially conceived in the 70s by architect Willy Van Der Meeren as temporary student housing, the prefabricated concrete modules were installed on the VUB campus. Since the ageing student housing no longer met current requirements, they were threatened with demolition. However, a case was made to keep these units for their architectural specificity and to prevent them turning into waste. To prove that the student houses can fulfil future needs of the university while still maintaining the identity of the campus, the Circular Retrofit Lab (CRL) project was launched.

The CRL project explored the reuse potential and the transformation capacity of the houses at different levels: building, space, constructive systems and components.

The modular concrete structure is reused. Renovating and reusing these structures limits the impact compared to a new construction. Other elements of the building, including concrete facade panels, had to be removed because they contained dangerous materials, such as asbestos, or were of insufficient quality. A new reversible envelope and new interior partitions were fitted into the reused structure. Demountable, adaptable and reusable solutions were tested and implemented. The solutions contained the use of dry connections, robust and reversible technical systems and the use of materials able to endue multiple reuses without being damaged.

Since the early development phase, a close collaboration with all the value network stakeholders was set up. Collaborating with industrial partners in this project showed how dependent the development of circular architecture is on innovations in the construction sector. The different circular solutions for facade systems, technical services, floor, ceiling and partition walls were developed and installed by different producers.


The rigidity of the prefabricated structure with its open plans allows a wide variety of alternative functions to be integrated in the building. For the Circular Retrofit Lab 3 representative functions were selected. © VUB Architectural Engineering

Different usage scenarios were developed for the student housing. The houses have the possibility to in the future transform into a dissemination space, a flexible workspace and an eco guest-house. These transformations include internal and external transformations, and the module’s multiple functional reconfigurations.

The façades' structure and construction


The development of the transformable façades encountered major challenges. The current building standards and the respect of the heritage value of the site had to be taken into consideration.

The concrete structure is modular. Therefore modular standardised solutions for the façade were pursued. A system of prefabricated interchangeable insulated wooden panels was used to fill in the stripped structure. As finishing layer, cement panels were used to preserve the visual identity. They were screwed on the watertight membrane by using wooden battens as intermediaries. They are interchangeable and can be re-used for the other facades of all student houses. The future transformation capacity resides in ensuring that the dimensional margins are allowing the switch. While the structural modules are standardised, the contractor identified some differences between them. A detailed figure of the façade panels is shown hereunder.


Modular preassembled façade panels were used to fill in the stripped concrete structure. They exist out of multiple materials that are connected in a reversible and dry way. © VUB Architectural Engineering


Composition of the façade panels. © BAMB Report D14

Designed for Change (or Circularity)?

This evaluation is done by using the 24 Design Principles for Design for Change. Only the principles at the Element and Building level are evaluated. The principles of the Neighbourhood level are not evaluated in this case.

The green-indicated principles are applied in the project. For the blue-indicated principles, it is not sure. The red-indicated principles are not applied. It is important to understand that it's not the goal to fulfill all 24 principles to obtain a circular building. It always depends on the context of the building, and how those principles are implemented. This evaluation is used as a reflection. All principles are discussed separately hereunder.


The Design for Change principles are used to evaluate the project on circularity and Design for Change. © OVAM

Element - Interfaces


1. Reversible joints in the building elements: The façade panels are demountable. They can be dismantled from the inside or from the outside. It is for instance possible to replace or upgrade the insulation layer of the façade without damaging any other elements.

2. Simple: The designers and suppliers tested different designs and systems which can be disassembled, but which are straight forward enough for the construction team on site to build the system in a reasonable time frame. Two aspects concerning ‘Simplicity’ were important to take into account. Firstly, the façade panels where partly preassembled when arriving on site.  Secondly, many systems already existed on the market and only slight changes or a change of function needed to be made. The panels were mounted by contractors, but who have never assembled this kind of façade system before. 

3. Speed: The joints are easily accessible.

Element - Components

4. Durable*: Selecting durable materials is important to lengthen the lifespan of the building elements and because the materials and building elements must withstand being reused, which includes the wear-and-tear of frequent transport and intensive use of construction products. The façade panels of the Circular Retrofit Lab consist of following materials:

  • Fibre-cement façade panels (outside finishing) (100 years)

  • Wooden battens (15-60 years)

  • Waterproof layer (30-60 years)

  • Insulation between wooden substructure (30-50 years)

  • Vapour barrier (sealing tape) (10 years)

  • Inside finishing (?)

5. Reused: No building components of different buildings or components of different industries is reused in this project. 

6. Compatible: The façade panels are dimensioned for the Willy Van Der Meeren-modules. The panels are thus compatible for a large number of campus buildings. However, we don’t know if the there is a market for them once they will be sold for another purpose.

Element - Composition

7. Pace-layered: The building layers are physically decoupled in functional and technical layers. The sequence of the different layers is decided according to the different life spans of the building layers. Moreover, the building is designed for different functions. By small changes in techniques and indoor walls another function can be housed.

8. Independent: Due to different vapour, air and water sealings, it was not possible to assemble the façade components completely independently of each other. However, those sealings are weaker connections than the other components. It is thus not a barrier for the demounting of one panel according to an adjacent panel. 

9. Prefabricated: The façade panels arrive preassembled on site. This pre-grouping of components allows accelerated assembly and disassembly. Mounting building components prior to assembly has in general also advantages when it comes to quality control, uniformity of building components, reduced waste generation and cost reduction in the building process. However, higher prefabrication rates could have been acquired in this project.

Building - Interfaces

10. Reversible joints between elements: Reversible connections have been used. 

Building - Components

11. Demountable: The dismantling of building elements is taken into account during the design phase. Installed elements can be dismantled separately without damage for reuse, repair, maintenance or replacement.

12. Reusable:​ Building components, such as the façade panels, can be reused on the other Varielstructures. All the façade panels have the same size. On the other hand, it could be that this limits the reuse of components to the project itself.

13. Expandable: One of the ideas for the renovation of the same Willy Van Der Meeren student houses, is to stack the modular structure and thus to add building layers (4 instead of 2). In the current CRL project it is not possible but applying the same principles a little different could generate opportunities. 

Building - Composition

14. Versatile: The design of the building is based on different usage scenarios. The CRL is equipped for future functional changes. It includes being able to adjust the techniques and the wet cells, to add or remove inner walls, etc.

*References lifespan materials: 

BVBS. (2010). Technical lifespan of building components for life cycle assessment of sustainable construction, on
BCIS. (2006). Life expectancy of building components: surveyors’ experiences of buildings in use: a practical guide. Second edition. London: BCIS. 353p.
Van Steenkiste, Jona. (2012). Longevity of building materials for massive construction. PhD Thesis, University of Ghent
SBR; VISSERING, C. (2011). Longevity of building products - methodology for reference values. Rotterdam: SBR. 32p.
Marteinsson, Björn. (2003). Durability and the Factor Method of ISO 15686-1. Building Research & Information 31(6): 416–426.


Tools used

More information

Report D14 – 4 pilots built & feedback report – Testing BAMB results through prototyping and pilot projects

CRL Pilot Blog

Project Page of the Circular Retrofit Lab on the VUB Architectural Engineering website



A project of


Engineering office

MK engineering.jpg

With the support of


In cooperation with

van roey.png
bao living.png

Take a look at

the other cases