Sustainable, Circular Renovation that Respects and Enhances the Original Design

Commissioned by Leiden University, De Zwarte Hond has completed the circular renovation and extension of the former Cluster Zuid building of the Faculty of Humanities. Architect Joop van Stigt designed Cluster Zuid for the Faculty of Humanities of Leiden University in the late 1970s. This impressive example of structuralist architecture was re-inaugurated on 8 October as Herta Mohr. It now offers 11,400 m² of space, plus car parking, with more than 700 teaching spaces and self-study places, two lecture theatres, work and meeting rooms, and common rooms. The building also houses the libraries of Leiden’s African Studies Centre and the Middle Eastern Studies program.

Photo credit: Eva Bloem

Photo credit: Stijn Poelstra

Photo credit: De Zwarte Hond

Better Orientation and Light Boost Unity

Cluster Zuid originally consisted of seven separate ‘houses’. Orientation in the building was difficult: the two courtyards were very similar and the narrow alleyways made the interior spaces dark. In addition, the dark ceilings and small windows, some with wired glass, created a closed and gloomy atmosphere.

To improve this, the central house was demolished and replaced by a new large central heart with lots of daylight. This makes it easier for visitors to better orient themselves from the central space, and the bright atrium creates a cohesive whole. The second floor was completely renovated and an eighth house with an anodised aluminium façade was added on the Maliebaan side.

Photo credit: De Zwarte Hond

Photo credit: Eva Bloem

Photo credit: Eva Bloem

The welcoming building opens up to the city: the entrance connects the square outside with the square inside, creating interaction with the environment. There is more space for people to meet, both inside at the coffee corner, and outside around the seating elements in the square. The building is part of the Humanity Campus, which will be improved in the coming years to better connect with the city and the green canal park. This building is the first step in this process.

A Renovation that Prioritizes Reuse and Sustainability

During the development of this building, 72% more sustainable measures were implemented than were required by the building regulations. By selecting high-quality materials with low emissions of unhealthy substances throughout the building, Herta Mohr now has a BREEAM Excellent certification. Insulation, solar panels, and a heat/cold storage system were also added.

Photo credit: De Zwarte Hond

Photo credit: De Zwarte Hond

In addition, new, efficient installations were installed to meet the high sustainability requirements. However, the existing structure could not support these changes, so the second floor was removed and a completely new structure was built on top of the building. This intervention has combined the separate ‘houses’ into one whole, with the technical installations fully integrated.

The reuse of most of the original building and façade is a notable achievement. Concrete columns from the demolished central house were reused in the extension. Other materials were also given a new life. For example, the old Sequoia redwood ceiling panels were transformed into wall cladding in the atrium. These slats were carefully worked on, stripped of nails, and milled in collaboration with the social workshop BWRI. The specific pattern of the slats meant that everything could be prefabricated and installed, minimizing waste.

Respect for the Existing

The renovation of the Cluster Zuid building complements and reinforces the existing design. The refurbished building reflects the spirit of Joop van Stigt as well as that of the present. By opting for renovation and sustainability, Herta Mohr has gained a new place in the collective memory of Leiden.

Photo credit: Stijn Poelstra

Photo credit: Stijn Poelstra

De Zwarte Hond

De Zwarte Hond is a design agency for architecture, urban planning, and strategy. Based in Groningen, Rotterdam, Cologne, and Berlin, more than 120 employees work on projects characterized by a surprising naturalness. With social commitment and craftsmanship, high-quality projects are created that fit the context and match user wishes and client visions.