Forestlines® Guariuba louvers combine architecture, material efficiency, ecology, and fire safety.
A new mobility hub with approximately 850 parking spaces is being constructed at the Arenberg Science Park in Leuven.
In collaboration with JHK Architecten, SVR-ARCHITECTS developed a vision for integrating the parking garage into the KCAP master plan. The design competition was launched by KU Leuven.
Together with JHK Architecten, Witteveen+Bos, and Istema N.V., this vision was further developed into an efficient, user-friendly, and sustainable building with a recognizable architectural appearance. Due to its prominent location on the Koning Boudewijnlaan, the mobility hub will become a defining element within the area. The architecture aligns with the innovative and future-oriented ambitions of the Arenberg Science Park.
STRABAG Belgium was awarded the contract for the turnkey realization of the new parking garage. The client is Parkeergebouw BV, a consortium of surrounding buildings supported by KU Leuven. The building has nine floors, each approximately 3,000 m², for a total surface area of approximately 27,000 m² and parking for about 850 cars.
Construction work commenced in the autumn of 2024.
A wooden facade that does more than just cladding
One of the most defining elements of the design is the open facade structure featuring thousands of solid wood slats. For this, the European patented Forestlines® slats were used.
Forestlines® combines solid wood with a minimal aluminium extrusion profile. The aluminium is not used to visually replace the wood, but rather specifically as a technical component within the system. This maximizes the proportion of solid wood while simultaneously allowing the structure to be designed for applications where high demands are placed on fire reaction.
For this project, Guariuba (Clarisia racemosa) was chosen, a sustainable hardwood species with a characteristic warm, golden-yellow to golden-brown colour. However, it is precisely the way in which the wood was selected for this project that makes the story special. At the sawmill, an existing overstock of 52 × 130 mm was available. Instead of disregarding this stock and having entirely new timber produced in a project-specific size, this available timber size was taken as the starting point for the production of the slats.
However, the existing remaining stock was not large enough for the entire facade. The additional timber was therefore sawn 'for yield'. This means that not only the most commercially viable and long timber lengths are selected from a log, but shorter usable sections are also included. As a result, a significantly larger portion of the available log can be converted into a high-quality application.
The various timber lengths were subsequently finger-jointed into long slats.
In this way, even short pieces of Guariuba, which would otherwise be much more difficult to use commercially, could become part of a high-quality architectural facade. At the same time, the finger joint ensures long, more homogeneous slats that can be applied in the facade with good shape stability. For us, this is an important aspect of sustainable material use: not only looking at the amount of renewable material, but also at the efficiency with which the available raw material is utilized.
Designed with bats in mind
Biodiversity also played a role in the technical construction of the facade.
Because the parking garage is illuminated at night, a light-blocking fabric was installed behind the open wooden slats. This limits light emission from the parking garage into the surrounding environment and protects the bats present from light disturbance as much as possible.
Naturally, this addition could not have any unknown influence on the fire behavior of the final facade. Therefore, the light-blocking fabric was not considered separately, but was included in the actual end-use construction during the fire tests.
Freestanding tested to B-s1,d0
The geometry of the facade also required a different approach than with traditional closed wooden cladding. The slats are positioned freely in front of the underlying structure. As a result, in the event of a fire, the wood can be exposed to flames and hot flue gases not only on the visible side, but potentially also on the rear side. The Forestlines® slats were therefore tested in a 'freestanding' configuration for this application. This took into account the exposure of both the front and back sides of the wooden slats; the underlying light-blocking fabric was also part of the investigated end-use configurations. The various tested configurations achieved fire reaction class B-s1,d0.
From gold to silver-grey
During assembly, Guariuba has its characteristic warm, golden-brown color. At this moment, this gives the enormous facade a strikingly vibrant appearance. But this is, of course, only one phase in the life of the building. Under the influence of sun, rain, and weather conditions, the untreated wood will gradually turn naturally grey. The warm tones slowly give way to a calm silver to grey patina.
This grey patina is already gradually becoming visible in some places.
Sustainability is embedded in the entire system
Especially in a parking garage, this project is a fine example of how various sustainability objectives can reinforce each other.
An existing timber stock was utilized. Additional timber was sawn for efficiency. Short lengths were given a high-quality application using finger jointing. The facade was designed with attention to the habitat of bats. The wood remains untreated and is allowed to turn naturally grey.
At the same time, the actual facade configuration, including the light-blocking fabric and the freestanding slats, was tested for its fire reaction. The result is a building in which architecture, material efficiency, biodiversity, and fire safety are not treated as separate themes, but form part of a single design.
For large-scale parking garages, Mobiliteitshub Arenberg beautifully demonstrates what is possible when wood is viewed not only as aesthetic cladding, but as a fully-fledged technical building material.
Solid wood, maximum material efficiency, attention to biodiversity, tested fire safety, and a facade that continues to evolve over time.
Houthandel Paulussen supplied the materials for this project. We do not realize projects ourselves, but we can refer you to the right craftsman or specialist.
