Expansion Headquarter Windkraft Simonsfeld AG

Central themes of our architectural practice are the development of sustainable building concepts and the use of renewable materials—particularly locally sourced timber, as well as straw and rammed earth. This approach is strongly rooted in material integrity, resource awareness, circular thinking, ecology, adaptive reuse, and sustainability in all its dimensions.
The aim of the Expansion Headquarter Windkraft Simonsfeld AG in Ernstbrunn (AT) was to create additional office space while integrating new areas for reception, gastronomy, and events—with a particular focus on fostering social interaction, both within the company and with clients.
The design expands the existing building, originally planned by the architectural office Reinberg, with a two-story volume along the street, framing a centrally located atrium that enhances communication and interaction between the existing and new structures. The new building is based on a clearly structured timber skeleton structure that ensures flexibility for future adaptations. A defining feature of the timber structure is the visible dovetail joinery; in general, the project emphasizes the exposure and visibility of the structural system within the interior. On the exterior, columns placed in front of the load-bearing structure serve as constructive weather protection.
The ground floor accommodates reception, meeting rooms, a cafeteria, and a multifunctional event space. The public area is characterized by a differentiated spatial concept that allows for flexible use. It is complemented by sheltered outdoor areas that enhance the quality of stay and provide additional possibilities for use. The upper floor houses modern office spaces arranged around the atrium, where visual connections enable intuitive orientation.
Two cores—constructed from locally sourced earth, rammed into 20 cm thick walls using climbing formwork—meet functional, aesthetic, and social requirements within the interior. They accommodate circulation and service spaces while enhancing spatial quality through seating niches, a tea kitchen and retreat areas. Through an innovative energy concept incorporating thermal activation of building components, they contribute to regulating the indoor climate. Heating and cooling energy are supplied via eleven additional geothermal boreholes. The entire roof surface is covered with photovoltaic modules, which generate the electrical energy required to operate the building.
A 14 cm load-bearing CLT layer forms the structural base for the integrated thermal activation system. The on-site fabricated rammed earth wall acts as a full-surface storage and regulating mass, releasing heat, coolness, and moisture as needed. Through slatted elements between timber beams, ceiling, and wall, the open and flexible areas surrounding the core are climatically regulated. As a result, the installation of a conventional air-conditioning system became unnecessary. The choice of materials also reinforces the building’s sense of place and serves as a defining element of the overall architectural identity.
The building already achieves a positive CO₂ balance during the construction phase. The project was certified with the highest rating of 1000/1000 points according to the Klimaakti- Gold-Standard. Furthermore, it received the Lower Austria Timber Construction Award 2025, the Special Prize of the Austrian State Prize for Architecture 2025, and the ZV Bauherr:innenpreis 2025.
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