Collegium Academicum,
Heidelberg, Germany

Innovative approaches for sustainable building methods

The Collegium Academicum in Heidelberg, Germany, brings together pioneering usage concepts, 'sufficient' building methods and community-based living to deliver a prime example of tomorrow's construction culture. This project was developed in cooperation with Mietshäusersyndikat, an organisation that supports the development self-organised apartment buildings in Germany. It has created a place that re-defines the concept of ownership, that shares out responsibility, and is guided primarily by a focus on social and ecological sustainability.

Community-based living – a fresh approach

This self-organised residence project was initiated in 2013 by a student group and serves as a beacon project for a new approach to communal living. This students' residence in Heidelberg turns a number of forward-looking concepts into reality: With the support of Mietshäusersyndikat, the building will permanently remain in the ownership of its residents and of future generations. In this way, it trying to counteract housing shortages and is deliberately promoting an alternative to profit-oriented development.

Flexible room concept combined with a 'sufficient building' approach

The project group has a clear guiding principle to enable communal, self-determined and ecologically responsible living. As part of this, a flexible room concept was implemented: flexible dividing walls developed jointly with the architects and the timber construction contractor allow the residents to choose between two room sizes. Many of the first people to live here deliberately went for the smaller option of 7 m², as this would allow for more shared spaces and commonly used areas. The project is also characterised by the principle of sufficiency, with less individual space and more communal areas. Small, flexible private rooms are combined with more generously proportioned rooms for communal use.

Sustainable, healthier living – with timber and pro clima

Particular emphasis was placed on ecological construction methods. The project was built in a largely CO₂-neutral manner and deliberately opted for timber and other ecological construction materials and products. In combination with carefully planned airtightness and insulation, the timber construction method delivers an improved indoor climate and increased energy efficiency. The project group with around 30 members opted for over a dozen pro clima solutions to prevent moisture damage to structures and to prolong the service life of the buildings. These product systems regularly achieve best-in-class results in independent tests for hazardous substances, which means they help to deliver healthy indoor air – an important component of ecologically responsible construction. This pioneering project demonstrates how modern building methods, sustainability and social principles can be successfully combined.

  • Key project characteristics: Involvement of a home-building syndicate, self-organisation by students, sustainable, passive house, self-managed, flexible spatial layout thanks to movable dividing walls
  • Location: Heidelberg, Germany
  • Year of completion: 2023
  • Client: Projektgruppe Collegium Academicum
  • Architects: DGJ Architektur GmbH, Frankfurt am Main, Germany
  • Timber construction contractor: Züblin Timber
  • Structural design: Ingenieurbüro Pirmin Jung
  • Construction method: Timber structure
  • Number of units: New-build: 46 residential units and additional communal areas, renovation of the existing building
  • Use: Accommodation for students and apprentices

This students' residence can boast a compact floor plan and layout, ambitious design standards and carefully planned usage concepts. The result is a welcoming living environment that fosters interaction and a sense of community.
Photo: © Philipp Garschke

Rainscreen facade on the new building.
Photo: © Uli Hillenbrand

Aerial view of the refurbished historical building. The existing building was extended and also renovated to achieve better energy efficiency.
Photo: © Philipp Garschke

The interiors of the new living units feature lots of aesthetically pleasing exposed structural timber.
Photo: © Myriam Thuerigen

Flexible dividing walls mean that room sizes can be adapted to create larger communal spaces.
Photo: © Myriam Thuerigen


Architectural models

The wooden model by DGJ Architektur GmbH on the left shows the site layout with the old and new buildings. The ground floor of the new building (right) features an assembly hall, workshop and multi-functional space, and there is a roof terrace over the covered area in the central courtyard – all of these spaces will foster social interaction and participation.
Images: © DGJ Architektur GmbH

The movable dividing walls allow the residential units to be adapted for changing life situations in the future.
Image: © DGJ Architektur GmbH


How was this project implemented?

The high degree of pre-fabrication of the timber construction elements means that the INTELLO airtightness membrane and the SOLITEX FRONTA WA breather membrane can be pre-installed in the workshop. Detail transitions such as pipe feed-throughs were sealed using pro clima grommets. Diese dienen der sicheren und dichten Durchführung von Kabeln und Rohren durch die Luft- bzw. Winddichtungsebene. A pipe grommet can be seen here in combination with the SOLITEX FRONTA WA facade membrane which is fitted behind the timber cladding and actively transports undesired moisture out of the building structure to the outside thanks to its pore-free TEEE functional film.

Pre-fabricated components obviously allow for quicker construction times on site.

Sealing of the building envelope is of critical importance on timber construction projects. This project uses pro clima INTELLO to deliver reliable internal airtightness, and in turn helps to fulfil passive house criteria as well as the requirements of the German KfW 40 Plus standard for energy efficiency.

The SOLITEX ADHERO membrane provides weather protection for the timber elements during the construction phase. When construction is finished, SOLITEX ADHERO remains in place on these components as a permanent airtightness layer between the individual apartment units.

Right from the planning stage, particular attention was paid to resource conservation, recyclability and the ease of separation of the construction materials. As a result, not only are the load-bearing elements and the walls and floor/ceiling elements made of timber… connections and joints have also been implemented using special wood-wood joints.

These joints adhere to the principle of using wood wherever possible, but also offer benefits from a building physics perspective: no condensation will form on these connectors. They are fitted into the appropriate holes and notches using special dead-blow mallets.

Flexible room layouts: Preparations for the installation of flexible dividing walls can be seen here - later on, the residents will be able to choose between two room sizes.

The EXTOSEAL ENCORS waterproof sill tape was used for base joints on windows and doors. With its high elasticity, this tape can be flexibly stuck over and into corners and provides excellent protection to underlying structures thanks to its verified resistance to driving rain. The CONTEGA SOLIDO IQ-D window-sealing tape and the pre-folded TESCON PROFECT adhesive tape were used for the interior window joints.

Collegium Academicum represents the project group's contribution to the trend in favour of more sustainable approaches and solutions in the construction industry. A high degree of pre-fabrication led to speedier building processes and helped to ensure high-quality execution, which is particularly advantageous in times where there is a shortage of specialist tradespeople on the job market.


Further information about this project:


The following pro clima products were used in this project: