Herta Mohr Building Renovation at Leiden University by De Zwarte Hond

Leiden University’s Herta Mohr Building, formerly known as Cluster Zuid, has undergone an extensive sustainable renovation and extension by the Dutch architecture firm De Zwarte Hond. Originally designed by Joop van Stigt in the late 1970s, Cluster Zuid is a prominent example of structuralist university architecture. The newly reimagined Herta Mohr Building was inaugurated on October 8, 2024, offering 11,400 m² of functional space and modern facilities while respecting its heritage-listed status.

Preserving History While Enhancing Functionality

The renovation carefully balances historical preservation with modern architectural interventions. Cluster Zuid originally comprised seven separate ‘houses,’ with narrow alleyways and small, wired-glass windows that created dim, disconnected interior spaces. To improve spatial orientation and daylight penetration, the central house was replaced with a bright, open atrium—the heart of the building.

New diagonal sightlines connect the surrounding structures to this central hub, creating a cohesive and intuitive layout. A fully renovated second floor and an eighth house with an anodized aluminum façade were added on the Maliebaan side, completing van Stigt’s original design vision.

Architectural Features and City Integration

Due to the building’s location within a protected cityscape, changes to the original façade were minimal. Iconic prefabricated concrete columns with conical tops, some featuring round balconies, remain fully visible, celebrating the structural elegance of the original design.

The building’s entrance now bridges the outside square with the interior square, fostering interaction and enhancing connectivity with the surrounding city. Inside, communal areas like coffee corners and meeting spaces promote social engagement, while outside seating areas offer spaces for students and visitors to gather. The Herta Mohr Building serves as the first step in the Humanities Campus renewal, connecting it more seamlessly with the Green Canal Park.

Sustainability and Circular Design

The renovation places a strong emphasis on sustainable architecture and circular design principles. During development, 72% more sustainable measures than required by regulations were implemented. By using low-emission, high-quality materials, the building has achieved BREEAM Excellent certification.

Modern energy solutions, including solar panels, insulation, and a heat/cold storage system, were incorporated, along with fully integrated technical installations. The second floor was reconstructed to support these upgrades, combining the previously separated houses into one unified structure.

Material Reuse and Adaptive Design

A notable achievement of this project is the reuse of existing materials. Concrete columns from the demolished central house were repurposed in the extension, and Sequoia redwood ceiling panels were transformed into atrium wall cladding. These elements were carefully stripped, milled, and prefabricated in collaboration with social workshop BWRI, reducing waste and emphasizing circular construction.

The renovation respects Joop van Stigt’s architectural spirit while creating a vibrant, contemporary learning environment. Through thoughtful design, sustainable interventions, and material reuse, the Herta Mohr Building now stands as a modern educational landmark in Leiden.

Collaboration and Project Team

The project was realized by Combinatie Cluster Zuid, consisting of Constructif and Koninklijke Kuijpers. Extensive collaboration with consultants and specialists, including Aronsohn, Buro Bouwfysica, BWRI, KCAP, C2N, Fokkema & Partners Architecten, Harryvan, Nelissen Ingenieursbureau, New Horizon, and Pieters Bouwtechniek, ensured seamless execution of the complex renovation.

All photographs are works of  Eva Bloem, De Zwarte Hond, Stijn Poelstra