In January 2011, the Swiss Society of Engineers and Architects (SIA) published a series of standards for existing structures. The standard entitled 'existing structures-bases for examination and interventions' specifies the principles, the terminology and the appropriate methodology for dealing with existing structures. This standard is complemented by a series of standards which treat specific items regarding 'actions on existing structures', 'existing concrete, steel, composite, timber and masonry structures' as well as 'geotechnical aspects of existing structures'. It is expected that these standards will provide effective solutions on questions such as higher live loads, accidental actions or the restoration and improvement of the durability of existing structures. This paper highlights major principles, in particular those related to risk-based safety, proportionality of interventions and updating of variables. Methodological aspects of the main activities, that is, examination of structures and intervention measures, are described.