RockyWood: Wood – Modular Timber Construction, Offenbach, Germany


The area at the harbor in Offenbach am Main with a view of the Frankfurt skyline is developing into a creative quarter. Between the listed “Heyne” factory building and a future new building of the Hochschule für Gestaltung, the project 'RockyWood' emerged, comprising two structures, 'Rocky' and 'Wood'.
The angular building 'Wood' is modularly constructed and consists almost entirely of wood. Approximately 500 prefabricated and technically pre-configured wooden modules enabled a short construction period. Additionally, the 2,600 m³ of wood sequester a CO2 load of around 2,500 tons. For fire safety reasons, the four upper floors of 'Wood' are connected via external walkways. These serve as meeting places and facilitate interdisciplinary work across floors.
In addition to office spaces on the upper floors and a publicly accessible restaurant on the ground floor, the building also meets social aspirations by providing 20 years of rent-free accommodation to the 'Nordend Offenbach' boxing club as a social integration project. The public square between 'Wood' and 'Rocky', known as the "Playground", is greened and equipped with seating and sports facilities. Connected to the Main by stairs, the square promotes urban life and serves as a meeting place for people.
For 'Wood', a building with high thermal insulation, a ventilation concept has been developed using decentralized facade ventilation elements integrated into the hollow floor, supporting the modular construction approach. This ventilation system also serves heating and cooling needs symbiotically. The decentralized ventilation units work with alternating flow direction and ensure to maintain a balanced ventilation, being used in pairs working together in a coordinated manner. The integrated heat exchangers keep energy consumption low. They use a large proportion of the extract air energy to preheat the supply air. Due to its wooden construction, 'Wood' has low thermal mass. Ceiling fans compensate for this as needed, ensuring thermal comfort through controlled increased airflow, "elevated airspeed".
The energy concept utilizes the primary energy-efficient Offenbach district heating, supplemented by waste heat from data centers. The idea of using river water for thermal energy via a heat pump was not implemented; instead, cooling is generated "classically" using compression refrigeration machines and rooftop cooling towers.
The timber façade is designed with vertical rainwater drains and fire barriers – with a camouflage or moiré effect. External sun protection shades the window areas. The daylight autonomy in the individual storeys was analysed using daylight simulations.
Dynamic thermal simulations were used as analyses to accompany the planning process. The local data set of the German Weather Service valid for Offenbach harbour, which is based on the weather data forecast for the year 2045, formed the basis for this. The proposed concept is therefore designed with an eye to the future.
The building has achieved DGNB Gold certification.
2024 Deutscher Immobilienpreis Green Project