700 m³ of lightweight concrete for a Berlin supermarket

The Rewe supermarket in Berlin-Friedrichshain is Germany’s first commercial building constructed using Liapor ultra-lightweight concrete. The building material serves both structural and insulating functions, enabling a monolithic construction method without the need for additional thermal insulation. Since its opening in 2023, this pioneering building has proven its worth in daily operation and was also awarded the “Fachmarkt Star” at the end of 2024.

Up to nine meters high and between 40 and 50 cm wide – these are the impressive dimensions of the exterior walls made of Liapor ultra-lightweight concrete that form the building envelope of the Rewe supermarket in Berlin-Friedrichshain. It is thus the first commercial building in Germany made of Liapor ultra-lightweight concrete, which has since proven itself in daily use and was also honored with the “Fachmarkt Star 2024” award at the 15th Frankfurt Retail Real Estate Congress in late 2024. The award is one of the most prestigious accolades for retail and commercial real estate in the German-speaking world. It recognizes projects that impress with innovative concepts, sustainable construction methods, architectural quality, and successful integration into their surroundings, thereby setting new standards for future-proof retail locations.

Load-bearing and thermal insulation functions

The project impressed the jury not only with its architecture, but above all with the choice of Liapor Infraleichtbeton for the building envelope. For Rewe Markt GmbH in Teltow, the project owner, the decision to use this building material was based on clear reasons: “The Liapor ultra-lightweight concrete used not only enabled monolithic and thus purist construction without complicated connections and details,” reports Dirk Heimann, Head of Construction at Rewe East. “Rather, it also stands out for its building physics and ecological properties.” Here, the building material fulfills both the load-bearing and thermal insulation functions within a single-layer building envelope. It offers the necessary strength and stability, as well as correspondingly low thermal conductivity. As a result, no additional thermal insulation was required, and all surfaces – both interior and exterior – could be finished in exposed concrete quality. The result is a homogeneous, uniform building envelope that appears as if cast from a single mold and effectively underscores the clean architecture of the ten-meter-high, 60-meter-long, and 50-meter-wide building. The building material also ensures sound insulation and provides a pleasant indoor climate. In addition, Liapor Infraleichtbeton is characterized by exceptional durability and longevity and, at the end of its service life, can be sorted by type and recycled. Another advantage: Infraleichtbeton has a lower _CO₂footprint than conventional concrete, as its production requires less cement with a lower clinker content.

The performance profile of the Infraleichtbeton is determined by the added Liapor expanded clay pellets. These consist of naturally pure Lias clay, approximately 180 million years old, which is fired into lightweight, porous pellets with a closed surface. They are dimensionally and structurally stable and ensure low weight, high thermal insulation, and frost resistance. In addition, they are non-combustible, chemically resistant, and regulate humidity. The concrete mix is always individually tailored to the construction project.

Groundbreaking milestone

In the case of the Berlin Rewe supermarket, a total of approximately 700 m³ of Infraleichtbeton in quality class ILC700/ILC800 was used. Heidelberg Materials AG, Königs Wusterhausen ready-mix concrete plant, served as the building material manufacturer and supplier, while Grötz Bauunternehmung GmbH in Niederdorf handled the construction work. However, preparatory work had to be done before the concrete was poured on site. This was because a general building code approval for the building material – which, according to the German Committee for Reinforced Concrete (DAfStb), will be available by the end of 2026 – did not yet exist at that time. Therefore, case-by-case approval (ZiE) had to be obtained for the project. This task was undertaken by Prof. Mike Schlaich of Schlaich Bergermann Partner, who has been researching the building material for more than 15 years at the Technical University of Berlin (TU) and developed the structural concept there in collaboration with the architects Baumgardt Franke. For the ZiE report, which also involved the Technical University of Dresden and the Federal Institute for Materials Research and Testing, fire wall tests were conducted for the first time, which the building material passed with flying colors.

This cleared the way for the phased pouring of the large-format concrete sections, and after several weeks, the structural work was completed by the end of 2022. This was followed by the construction of the roof and the installation of building services, which enable CO₂-neutral operation of the building. In May 2023, after a total of four years of planning and construction, the supermarket, with a gross floor area of approximately 9,000 m², was officially opened. “The new construction project using this special building material and on this scale was uncharted territory for everyone involved, but we were able to successfully realize it together,” concluded Dirk Heimann. “In particular, designing the walls made of Liapor ultra-lightweight concrete in a way that is feasible in terms of both building materials and structural analysis is one of the outstanding achievements in the realization of this location.” The Rewe supermarket is thus a groundbreaking milestone that meets high economic and ecological standards and demonstrates how Liapor ultra-lightweight concrete successfully opens new avenues for contemporary and sustainable construction.