Waldau Multifunctional School (OSW)
A place of learning and living designed for the next generation
With the Waldau Multifunctional School, Kassel has gained an educational space that is much more than just a school complex. The new OSW combines learning, social life and urban life in a hybrid wooden building that is open, flexible and carefully designed. In addition to accommodating up to 950 pupils, the complex offers a library, a youth centre, music rooms and workshops, making it a real landmark for the entire neighbourhood.
For this project, we at Rubner have the privilege of constructing the wooden load-bearing structure and the entire building envelope. For us, the Waldau Multifunctional School is a perfect example of how cutting-edge architecture, modern pedagogy and sustainable construction can be combined in a unique and exceptional project.
School and community under one roof
The Waldau Multifunctional School is part of a long tradition of innovative educational models. The new building continues this trajectory by transforming it into space. The heart of the project is a central atrium with a large staircase, designed as an open meeting place, an event space and a learning environment. The teaching areas are organised in clusters, allowing for a combination of traditional lectures, project-based work and inclusive learning.
The interplay of the building’s volumes creates a variety of indoor and outdoor spaces. Roof terraces, learning islands and open staircases provide ideal environments for concentration, discussion and relaxation. The outdoor spaces are designed as a campus that consciously opens up to the neighbourhood. An existing path extends to the atrium, connecting the school to its surroundings. In this way, the school building becomes a true gathering place for children, young people, families and residents.
Wood, a key element of sustainable architecture
In the competition, the city of Kassel placed great importance on sustainable and climate-friendly construction. The Waldau multifunctional school meets the requirements of DGNB certification, with a particular focus on parameters such as flexibility of use, indoor climate quality, healthiness of spaces, efficient management, durability of the structure and multifunctionality. The choice of a hybrid timber construction system, offering great flexibility and a minimum number of load-bearing walls, is the direct architectural response to these requirements.
The lightweight timber structure significantly reduces the time required to complete the structural elements, by around 30 to 40% compared to traditional construction solutions. At the same time, the choice of materials reduces CO₂ emissions by around 50%. The school will be built to the Effizienzhaus 40 standard as a highly energy-efficient building, requiring only a fraction of the energy needed for a comparable building that only meets the minimum legal requirements. Photovoltaic systems, ventilation systems with heat recovery and a highly insulated envelope contribute to the achievement of these objectives.
The wood used also acts as a CO₂ reservoir, as the carbon absorbed by the trees during their growth remains stored in the building structure. The Waldau multifunctional school is thus a concrete example of how school construction can actively contribute to climate protection.
Our contribution: structure, envelope and precision
For the Waldau Multifunctional School, we are supplying the timber-framed structure and the entire timber-clad exterior envelope. The project is divided into two construction lots, East and West, extending up to four storeys, connected by a central atrium and several intermediate levels.
The load-bearing structure is designed as a timber frame system with glulam uprights and bottom chords, largely glued in blocks, in order to support high loads and cover large spans. The floors will be constructed with a ribbed X-Lam structure. In total, approximately 13,000 m2 of ribbed X-Lam and glued laminated timber panels will be used for the floors, as well as approximately 1,500 m3 of structural components, including block bonding.
The building envelope consists of approximately 6,000 m2 of timber-framed exterior walls, including joinery and sun protection systems. In addition, there are wood-aluminium windows, a wood-aluminium mullion and transom façade, and a series of prefabricated elements, finished in the factory down to the smallest detail. The high degree of prefabrication reduces interfaces, speeds up assembly and guarantees a consistently high level of quality.
Topping out ceremony
On 26 May 2026, we celebrated the topping-out ceremony of the OSW – Offene Schule Waldau – together with around 200 guests of GWG Projekte für die Stadt Kassel, and moments like these remind us why we love our work. The school community, representatives from politics, administration and the project partners came together to celebrate this moment. With the raising of the traditional wreath and the topping-out speech, what carries this project became tangible: a strong sense of togetherness.
In their speeches, City Climate Councillor Simone Fedderke emphasised: “The OSW is a pioneering project for Kassel: here, innovative timber construction meets forward-looking circular management. The fact that we were able to reduce the ecological footprint by a quarter already during construction proves that sustainable building and modern pedagogical concepts go hand in hand.”
Mayor and Education Commissioner Nicole Maisch added: “Open learning landscapes, the Makerspace, spaces that adapt to learning rather than the other way around – this is innovation you can touch.” (Source: Press release from the City of Kassel, 27.05.2026)
The building, up to four storeys high, for the Offene Schule Waldau consists of a load-bearing timber skeleton structure and a building envelope in timber frame construction. In numbers: 128 glued laminated timber columns. 788 floor elements. 280 prefabricated wall panels – delivered complete with windows and sun protection, ready for installation. All manufactured from 4,700 m³ of PEFC-certified timber from Styrian forests. A quantity that regrows there in less than one day.
But what impressed us on that day were not the numbers. It was the pupils, who were able to watch their school grow before their eyes – and who in that very moment already called it their own – thrilled by the size, the abundance of wood and the brightness. In a collaborative participatory activity, young and old guests recreated the school on a small scale. From around a thousand wooden cubes – made from the timber laminations used in the construction – a miniature version of the building emerged piece by piece.
From digital model to construction site
The Waldau multifunctional school is designed entirely digitally. The BIM model not only shows the building’s geometries and components, but also integrates processes, interfaces and future usage scenarios. For us, this model forms the basis for precise planning of the work and assembly phases. It coordinates the construction of the structure, floors, walls and façade to ensure smooth execution on site.
And as the design phase progresses, the building is already taking shape in virtual space. On the homepage, the BIM model becomes a visual experience that allows you to understand the spatial organisation of the clusters, the atrium and the learning spaces. The architecture thus takes shape long before it is actually built.
A glimpse into the manufacturing process
Even before the first wooden elements are assembled in Kassel, much of the work has already been done in our workshops. A photo gallery allows you to follow the production of the various components step by step, seeing how the individual slats are assembled into glued blocks, how the ribbed panels for the floors are manufactured, and how the wall elements are assembled and then completed with windows and sun protection.
These images clearly show why off-site prefabrication guarantees excellent quality. Dimensional accuracy, production in a dry environment, reproducible processes and team coordination ensure that everything runs smoothly on site. The project team, the school and the city of Kassel can thus see how the design idea is gradually transformed into a real building.
The ideal construction site: organised, quiet, forward-looking
Even on the construction site, the value of an intelligently designed timber construction is evident. Aerial images show a well-organised work area, clear logistics flows and a structure designed from the outset for prefabrication. This approach reduces the amount of materials on site, limits noise emissions and speeds up progress.
The fundamental steps towards the new school
From the award of the contract in 2021, to the design, laying of the foundation stone and start of assembly of the timber structure, to the completion of the work scheduled for 2027, the journey towards the new school is marked by many key moments. For us at Rubner, the crucial stages include the start of the detailed design and workshop production, the assembly of the first uprights and floors, and finally the start of the building envelope construction.
Building the school of tomorrow together
The multifunctional Waldau School is based on a deep conviction: space is more than just a shell. It influences learning opportunities, a sense of community and everyday life. When a city, a school, architects, designers and builders work together on this idea, a place takes shape that goes beyond the traditional concept of a school.
We are proud to be part of this project thanks to our expertise in large-scale timber construction. With our team, our experience and our passion for wood, we are helping to create a space for learning and meeting in Kassel that will serve many generations.
