Les Trèfles Primary School

Les Trèfles Primary School

Árter Architects
Anderlecht, Belgium | View Map
Project Year
Primary Schools
Stories By
Árter Architects

Firestone Building Products EMEA

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Le Trefles School

Árter Architects as Architects

Seamlessly blending sustainable design, educational innovation and architecture, Les Trèfles Community School in Anderlech comprises four overlapping circular volumes connected by wide walkways and an adjacent gymnasium. The circular design draws from research indicating that round shapes stimulate movement and physical exercise. In addition to its inventive layout, the school is also highly sustainable, easily achieving a passivehaus standard. Energy-efficient building strategies such as heat recovery, use of natural light, quadruple glazing with build-in sun protection system, rainwater recycling and a spectacular 7000 m2 green roof were implemented.  

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The project for the Les Trefles community school in Anderlecht is characterised by progressive, energetic and environmental achievements, which easily meet the passive standard. Research indicates that the round shapes used in the project stimulate movement, resulting in a potential average increase in physical exercise of 20%. The complex style of these shapes improves interpersonal relationships and also offers an interesting architectural statement for the neighbourhood, of which the development is moving ahead quickly.


The building and electrical installations are all aligned with one another in order to achieve an optimal energy consumption, water management and indoor climate. All nodes have been specified and simulated using calculation software according to the necessary insulation and airtightness of the building. The green roof, created by ZinCo Benelux and rich in biodiversity, contributes to a pleasant indoor climate. The outdoor area around the school has been designed as a natural structure: vegetable gardens, green facades and roofs, ponds.


The sustainable water management is achieved both by retaining rainwater on site for as long as possible using the green roof, and also by reusing rainwater so as to restrict the consumption of drinking water.


The projects hopes to set an example in terms of energy performance, but it also wants to stimulate the children's awareness of energy management by teaching them the correct way to use it carefully. This means that sustainability makes up a vital element of the educational project.

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Firestone makes Belgian school watertight

Firestone Building Products EMEA as Roofing

To ensure a watertight construction for the 7,000 m2 green roof at Les Trèfles Community School, Árter Architects specified an UltraPly™ TPO thermoplastic polyolefin roof system. The adhered build-up consists of a self-adhesive bitumen vapour barrier membrane, two layers of 15 cm-thick PIR insulation board and 1.5 mm-thick Firestone UltraPly™ TPO single-ply membrane, fully adhered with contact adhesive. The green roof was then installed on top of this. In addition to a watertight assembly, the choice of roofing membrane was also based on a Life Cycle Assessment (LCA) taking into consideration the total environmental impact of products during their entire life cycle

More from the Manufacturers:

The stricking Les Trèfles building is a school and sports complex that has room for 750 pupils. 


Its UltraPly™ TPO thermoplastic polyolefin roof system effectively waterproofed the structure’s 7,000 m² roof.


The client chose Firestone’s UltraPly™ TPO roofing system installed by Firestone Master Contractor MUTEC, who has a great deal of expertise and experience in TPO waterproofing and green roofs.


The 7000 m² roof surface was fitted with an adhered roof build-up consisting of a self-adhesive bitumen vapor barrier membrane, two layers of 15 cm-thick PIR insulation boards and a 1.5 mm thick Firestone UltraPly™ TPO single-ply membrane, fully adhered with contact adhesive. An eye-catching green roof was installed on top of it.


The choice of roofing membrane, as well as all other construction materials, was determined based on a Life Cycle Assessment (LCA), which takes into consideration the total environmental impact of products during their entire life cycle.

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Sustainable School turns a new Leaf

Rockpanel as Manufacturers

Enhancing a circular theme with a focus on sustainability, Rockpanel Chameleon boards by Rockpanel were selected as a cladding material for Les Trèfles Community School. Directly bonded to ensure a clean aesthetic, the façade solution achieves a BRE Green Guide A+ rating. In addition to boasting impressive environmental merits, the boards enhance the finished appearance of the building as they are equipped with a crystal layer that, depending on perspective and sunlight, shifts and changes in appearance throughout the seasons.  

More from the Manufacturers:

The new Les Trèfles primary school in Anderlecht, Belgium seamlessly blends educational innovation, sustainable design, and attractive architecture. The exceptional design, by architectural firm Árter of Brussels, was therefore selected for the ‘Exemplary Buildings 2012’ call for projects of the public authority Brussels Environment-IBGE/BIM.

The school, which accommodates 750 children from ages 4 to 12, consists of four partially overlapping circles connected by wide walkways and an adjacent gymnasium. The three largest circles have classrooms in the 'skin' and sheltered round playgrounds in an open core. A two storey circular building provides the entrance, technical areas and a caretaker’s lodge.

A new kind of primary school: beautiful, sustainable and stimulating

Árter based the unique shape of the school on the name of the neighbourhood, Les Trèfles (The Clovers), and on studies by Japanese professor, Mitsuru Senda. 'He showed that round play areas elicit up to 20% more spontaneous movement,’ says architect Patrick Vonck. 'Moreover, circles have 20% less facade for the same area. Because of this, I could literally break up the standard school structure with enclosed hallway, and use that corridor area for extra play space.'

In addition to the inventive layout, Árter’s school is also highly sustainable. With an energy use of only 12kWh/m2 per year, it achieves performance equivalent to that of a passivhaus building. To achieve this, various techniques such as heat recovery, natural light, quadruple glazing with a built-in sun protection system, green roofs, and rainwater recycling were used. Construction materials were also chosen based on their full lifecycle environmental impact.

For the facade cladding, Vonck chose, among other things, Rockpanel Chameleon boards. The facade cladding has been directly bonded to support the school’s clean aesthetic. 'I was pleasantly surprised that I could specify a product which enhances the ‘cyclic’ aspect of the school, and at the same time achieve a BRE Green Guide A+ rating. Materials must be carefully chosen in Ultra-low-energy buildings, so it is important that we are able to rely on manufactures to provide the necessary testing and performance certification and onsite support', states Patrick Vonck.

Panels that fit in wonderfully with the seasonal changes

According to Vonck, the boards also enhance the architecture of the building. 'They are equipped with a crystal layer that, depending on the perspective and the sunlight, has a surprising effect on the colour perception. The colour variation of the panels fits in wonderfully with the seasonal changes in the vegetable gardens around the circles.’ Rockpanel Chameleon boards were also routed to provide signage around the school building. The products are insensitive to weather conditions and moisture. As a result, after engraving, no special treatment was required, not even for the visible base plate. Thierry Laroy of general contractor CFE Brabant also highlighted the ease of handling as an important point: ‘I had no previous experience with the panels, but installation was no problem.’

The result is a beautiful complex of buildings in which, in addition to Rockpanel Chameleon, Rockpanel Natural and Colours are also used. Even before delivery, Vonck has received many positive reactions. 'The local administration and other school boards are enthusiastic, there is extensive media interest, and neighbourhood residents have been admiring the magical colour changes. Personally, I feel it is a very successful project. The cyclic theme, the focus on sustainability and the material choice all combine and reinforce each other to create the ideal result’, concludes Vonck.

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