Architects are facing major challenges today. According to the Swiss Federal Office for Environment, 84% of waste in Switzerland comes from the construction industry – 30% more than in Germany, for example. No matter how sustainably we manage to construct new buildings, the most sustainable measure is always the preservation of existing buildings and their continued use through renovation, conversion and transformation. Nevertheless, it is equally important not to adopt a dogmatic stance, but to assess each situation specifically. New replacement buildings can be socially sustainable if, for example, they create urban upgrades or contribute to more urgently needed living space. Building land is becoming scarcer, especially in cities and conurbations. For this reason, densification and inward development are becoming increasingly important. In the case of Swiss replacement new build practice, every demolished apartment is usually replaced by two new ones on average, while the living space is actually tripled. (Source: SBV, Schweizerischer Baumeisterverband).
The brief of this specific competition is asking to demolish an existing building, although the allowed density can be reached by a combination of backward extension and addition of two new floors to the existing structure. Also, the requested flat-type mix of largerly 4 and 5 room apartments is already to be found in the existing building. Due to building law regulations, a new built structure will likely result in a similar urban setting as the existing.
We are firmly convinced that, under the given circumstances, the most sustainable, ecological and economical solution is not to build a new building, but to retain the existing building and extend it. In our project, the ratio of newly built to existing floor area is approx. 1000m2 to 2000m2. This means that a large part of the primary construction, including CO2 / embodied energy, does not have to be newly built. Architecturally, we want to discover potentials in the seemingly worthless and banal buildings from the 1940s. The premise of the project is therefore to reuse and improve what already exists and to transfer it to a new life cycle. Selective structural interventions in the existing buildings are aimed at creating a new quality of living in the formerly cellular floor plan arrangements. A full storey and an top storey will be added to the existing building as a lightweight timber construction, which contains the additionally required small apartment typologies.
