The renovation of the Concert Hall at Kiel Castle updates a post-war cultural building while retaining its architectural character. Designed between 2019 and 2025 by gmp · von Gerkan, Marg and Partners Architects, and bbp: architekten, the project upgrades the 1961–1965 concert hall rather than replacing its existing structure.

The approach responds to contemporary acoustic, technical, accessibility, and operational requirements while preserving as much of the original building fabric as possible.

The sustainability strategy centers on retaining the embodied resources already present in the building. The existing reinforced-concrete structure and principal load-bearing elements were preserved, while interventions were limited to essential functional improvements.

Natural stone facades and foyer walls were restored, with approximately 70 percent of the existing natural-stone panels retained and reused. The project also refurbished concert-hall seating frames and reused lighting fixtures, extending the service life of components that might otherwise have required replacement.

Retaining the existing structure

The decision to renovate rather than replace the concert hall forms the project’s primary sustainability strategy. Preserving the existing structural frame avoids much of the material extraction, manufacturing, and construction associated with a replacement building. The intervention also restores the original architectural proportions while incorporating contemporary thermal insulation, airtightness measures, and energy-efficient building services.

The existing natural-stone cladding was carefully dismantled to allow high-performance thermal insulation to be installed behind the facade, after which 70 percent of the stone was remounted. The remaining 30 percent was sourced from a regional supplier to match the existing material while limiting transport requirements.

This combination of selective dismantling, reuse, and regional sourcing reduces demand for new facade material while maintaining the building’s original appearance.

Upgrading the envelope

Energy performance was addressed through upgrades to the building envelope and technical systems. The foyer received an energy-optimized post-and-beam glass facade that follows the proportions of the original structure. New solar-control glazing improves thermal performance and helps limit summer heat gain.

Building services were completely renewed, bringing the technical infrastructure in line with contemporary operational requirements.

Reusing interior components

Material conservation extends into the interior. The original concert-hall seating frames were retained and upgraded through reupholstering and technical maintenance rather than replaced. Existing lighting fixtures were also reused, while LED backlighting behind Corian panels supplements the original lighting concept.

The specification also includes PEFC-certified smoked oak parquet, providing a responsibly sourced timber finish for interior surfaces. In other areas, linoleum flooring was installed across the basement, main circulation staircases, and backstage offices. 

Designing for future adaptation

The renovation treats continued use as part of the building's resource strategy. Rather than restoring the concert hall to a fixed historical state, the design accommodates contemporary requirements and introduces additional programmatic flexibility. A new multifunctional hall was added on the upper floor, while the expanded Förde Foyer provides additional space for social and informal musical activities.

Within the concert hall, new lifting platforms replace manually operated stage elements, allowing faster changeovers and more flexible use. Acoustic improvements, upgraded technical infrastructure, and reorganized circulation allow the existing building to support current concert and event requirements.

Reversible interior construction

New fit-out elements were designed with future modification and material recovery in mind. The project documentation identifies dry, reversible hanging and mechanical fastening systems for new architectural components, including bespoke Corian wall cladding and rolled-steel fixtures.

Mechanical rather than adhesive connections allow components to be removed without damaging adjacent materials. The design also avoids non-recyclable composite thermal insulation systems, supporting the separation of materials into individual waste or recycling streams at the end of their service life.