This study explored the potential redevelopment of a typical apartment building dating from the early 1950s. The property consists of two interconnected building volumes and remains in generally good structural condition. During the 1990s, the owners already modernised selected areas such as kitchens, bathrooms, and windows. Nevertheless, the building no longer met current energy performance standards.
At the same time, the site offered additional development potential. Therefore, the study examined various strategies to enhance the building from an architectural, energetic, and economic perspective. The main focus lay on sustainable densification and a future-oriented energy concept.
Together with the client, the planning team defined several key objectives. On the one hand, the building envelope required significant energetic improvement. On the other hand, the project aimed to create additional living space while increasing the long-term value of the property.
The study included the following aspects:
As a result, the concept combined ecological and economic considerations within a holistic redevelopment strategy.
An important part of the study focused on the possible addition of an attic storey. For this purpose, the planning team analysed the removal of the existing pitched roof as well as the structural requirements of the existing building.
The proposed additional level was designed as a prefabricated timber construction. This building method allows efficient construction processes while also providing sustainability and high energy performance.
The attic extension included three new residential units:
In addition, the study examined the integration of a passenger lift within the existing stairwell in order to improve long-term accessibility.
The energetic optimisation of the building envelope formed a central aspect of the investigation. Consequently, the study evaluated several refurbishment strategies for façades, windows, and roof areas.
The proposed measures included:
Furthermore, the concept proposed an extensively greened flat roof for the new attic level. This solution would not only improve ecological performance but also enhance the indoor climate during summer months.
Alongside the energetic refurbishment, the improvement of residential quality also played a significant role. The existing balconies no longer met contemporary standards and provided only limited outdoor space.
For this reason, the study developed new balcony concepts with larger dimensions and more functional layouts. The design proposed galvanised steel structures that integrate clearly and elegantly into the architectural language of the building.
As a result, the apartments would have gained significantly more attractive and usable outdoor areas.
The study also investigated several options for modernising the building services systems. The aim was to establish an energy-efficient and future-oriented supply strategy for the entire property.
The proposed concept included:
Together, these measures formed a sustainable overall strategy for reducing energy consumption and increasing the use of renewable energy sources.
During the study phase, several technical and urban planning constraints became apparent. In particular, the existing parking situation represented a significant challenge. In addition, the structural conditions complicated the integration of further accessibility elements.
Therefore, the planning team evaluated different solutions. These included additional parking spaces on the site, external garage facilities, and a mobility concept featuring electric charging stations and bicycle parking areas.
The study clearly demonstrated the complexity involved in upgrading existing residential buildings within an urban environment.
The investigation revealed considerable potential for the energetic and architectural redevelopment of the existing property. In particular, the combination of sustainable densification, renewable energy systems, and contemporary architecture would have significantly enhanced both the building’s value and residential quality.
At the same time, the study highlights the importance of carefully analysing technical, economic, and urban planning conditions during the early stages of project development.
| Area of expertise | Addition / Alteration / Renovation |
| Collaboration | Bötschi Architekturbüro SIA GmbH ADP Baumanagement GmbH |
| Status | preliminary project completed |
| Year | 2023 /2024 |