Adjustments to the ISOS

Switzerland has the world’s only inventory of heritage sites of national importance (ISOS) that covers the entire country. The inventory records the quality of around 1200 residential estates, rather than individual buildings. This makes it an important basic tool for the lasting preservation of architectural and cultural heritage values. All properties in the inventory can be freely viewed in a digital map application.

In recent years, the ISOS has attracted particular attention due to occasional ambiguities in its practical application. The demand for higher structural and spatial density, the aspiration for high-quality residential areas and various other requirements for the urban environment – such as climate, energy and biodiversity – are leading to a continuously evolving complexity of the rules, schemes and processes that have to be taken into account.

The interdepartmental working group on building culture therefore organised a roundtable forum led by the Federal Office of Culture FOC in the spring of 2025 with representatives from the public sector, the private sector and civil society. All of the delegates were in agreement that the ISOS should not become an obstacle to high-quality urban densification, housing construction and the energy transition, but rather should play an active part in the harmonious development of our towns and villages while safeguarding their identity. Together, they resolved to clarify the statutory provisions and to strengthen the procedures for the efficient application of the ISOS system. The recommendations of the round table forum were presented to the political decision-makers at the end of June, who will now decide on the further course of action.