The start of construction was initially delayed due to a late planning application; the project is now held up by an appeal process. In the Canton of Zurich, construction work may only begin once appeals have been resolved, the appeal period has expired and the local authority has granted planning permission.
In Thalwil, this concerns the municipality-owned housing estate at Breitelistrasse 11 to 21. Four buildings comprising a total of 58 flats are to be built there. The project will replace houses in the Breiteli housing estate that are over 100 years old. On 28 September 2025, voters approved a building loan of 33.895 million Swiss francs for the new development.
Affordable replacement development blocked
The replacement development is central to the municipality’s housing policy, as the new flats are planned to be in the affordable segment. The referendum documents explicitly linked the project to moderate rents and a rent based on costs. The plans also provide for a high-density development with a variety of flat types and communal open spaces.
The delay therefore affects more than just a single planning application. It also postpones the replacement of existing council housing and slows down the creation of additional affordable housing in a well-connected location. According to the original timetable, construction was due to start as early as 2026.
Decision with an uncertain outcome
According to the latest reports, the cantonal building appeals court is expected to rule in the coming weeks. If the decision goes in favour of the municipality and there is no further appeal, work could begin in March or April 2027. If the case is referred to the Administrative Court or, subsequently, to the Federal Supreme Court, the project is likely to face further delays.
For the property sector, the case follows a familiar pattern. Even a housing development that has been politically approved and is at an advanced stage under planning law remains blocked in the canton of Zurich until all legal appeals have been exhausted. Particularly in the case of local authority projects offering affordable rents, this means that not only is construction postponed, but so too is the date on which urgently needed flats actually come onto the market.
