Prefabrication – the key to speedy construction

The timber construction work began in August 2023 and was due to be completed by the end of December 2023 – an extremely ambitious time schedule of only five months for a high-rise building of this scale. Completion on time was only possible thanks to extensive prefabrication at the Aichach plant of the timber construction company ZÜBLIN Timber. There, fully insulated timber panel elements were manufactured for the external walls – totalling over 6,000 m^² – which then simply had to be installed on site. To facilitate transportation, 5.5 m long façade elements were screwed together on site to form the standard 11 m units. Windows and parapets were fitted at the factory so that the building frame and façade could be installed in a single step, further speeding up construction.

Fire safety – keeping timber exposed thanks to a misting system

From a design point of view, the planers of the UmweltHaus wanted to make sure that the structural framework made of BauBuche and spruce was visible throughout the interior of the building – something that is by no means easy to achieve in a 52 m high-rise. “A celebration of a structural framework with a striking visibility of timber taking centre stage” is how architect Ingrid Spengler described the vision. In Bavaria, strict fire safety regulations apply to all buildings in class 5 (GK 5) with exposed timber. Consequently, the BauBuche and spruce components had to be designed so as to provide a fire resistance rating of 90 minutes (REI 90), taking into account the rate of combustion. When factoring in the non-load-bearing burn-off allowance, it becomes apparent that the chosen materials allow for extremely slender building elements. Critical joints were eventually fitted with milled infill panels, and exposed steel components were coated with fire-retardant paint. In addition, a highly efficient high-pressure water mist system (HPWM) was installed, which extinguishes fires using a minimal amount of water and therefore causes less secondary damage that a conventional sprinkler system. Also, there are fire alarms throughout the building, with a direct link to the Nuremberg fire Service.

From the very start, the project was supervised by both private and public fire safety experts, as the German model guidelines for high-rise timber buildings did not cover all aspects of the UmweltHaus construction. The bespoke fire safety solutions developed in this project will assist planners when seeking planning permission for other high-rise buildings made of timber.

Photovoltaic façade – weather protection and energy source in one

The building envelope is as innovative as the timber structure, as the entire façade is clad in photovoltaic modules. From the street, the building looks like a green-tinted glass structure. It is only at second glance that it becomes clear that the entire surface is actually generating electricity. For the designers, it was important that their project would not stand out as a technical showpiece or an overtly “green” building. According to the architects, this timber high-rise fitted with a full-surface, active photovoltaic façade is the first of its kind in Germany.

Great reception

The topping-out ceremony in February 2024 attracted widespread media attention. Mayor Marcus König described the UmweltHaus as a landmark project for Nuremberg, while State Secretary Rolf Bösinger remarked: “In terms of its size and the amount of timber used in its construction, this high-rise building is truly unique in Germany.” In June 2025, the project won the IHK Real Estate Prize for Middle Franconia in the innovation category. The award recognised the extensive use of regional building materials and the consistent circular economy approach.

Transferable solutions

The UmweltHaus demonstrates clearly that BauBuche is the ideal material for projects where standard layouts and conventional approaches reach their limits – for example because they would restrict building heights, lead to posts interfering with the use of interior spaces or would require excessively large connectors. BauBuche also is the perfect solution where loads and traverse compression stress are extremely high. Such demands arise typically where land prices are high, in the construction of flexible office, research, educational and industrial buildings and where proprietors seek to complete prestige projects of a sophisticated architectural design. In such developments, BauBuche often provides the perfect solution, especially if spruce glulam is not an option, be it from an economic or a design point of view.

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