The planning selection procedure for the residential and commercial building at Gattikerstrasse 5, Zurich-Hirslanden, clearly demonstrates that the preservation of existing buildings and the safeguarding of socially acceptable housing is not limited to large-scale housing developments but can also be achieved on a comparatively small scale. With the complete refurbishment of Charles Steinmann’s building with 12 small flats, the City of Zurich, which commissioned the project, is aiming to preserve very affordable residential and commercial space, while minor adjustments to the floor plans are intended to enable age-appropriate flats. ‘Small intervention, big impact’ is the title of the successful submission by the team led by Gutschoep Architektur, and not without good reason. As part of careful preliminary investigations with all specialist planners, the layout was examined for qualities and deficits, from which measures were derived.