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43 apartmentsnew rental apartments plannedon Sigma and Tau
UrbanHome · Zurich news
Sihlcity Zurich: UBS plans 43 new apartments on the roof
Forty-three new rental apartments are planned on the roof of Sihlcity in Zurich-Wiedikon. The building application published on 21 August 2026 calls for two additional storeys on the Sigma and Tau buildings; most apartments are expected to have 3.5 rooms and be positioned in the upper price segment. Media reports mention a possible construction start in 2028 – but the current project has not yet received final approval.
Author: Nikita von Niederhäuser, UrbanHome real estate expert Updated: · Reading time: approx. 12 minutes
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2 storeysadditional rooftop extensioninfill development of the existing site
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54–146 m²planned living areasmostly 3.5-room apartments
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Building applicationproject not yet definitively approvedPublished on 21 August 2026
Sihlcity project
Sigma.
Tau.
Two storeys.
The published project description envisages a substantial expansion of the existing Sihlcity site.
Kalanderplatz 2 · Zurich-Wiedikon
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Rooftop extensions to Sigma and Tau
Two additional storeys are planned on the buildings “Sigma” and “Tau”. The proposal includes 43 apartments, enclosures for existing cooling equipment, shared outdoor space and changes to the surrounding grounds.[1]
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Living on the roof
Media reports describe the apartments as a residential development on top of the Sihlcity complex. Some would be located above the car park and others on the section of the building along the Sihl river.[2]
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Several owners
“UBS plans” is a simplification. Sihlcity is owned by a co-ownership group comprising several real estate investment vehicles. The official Sihlcity website lists UBS 1a Immo PK, UBS Investment Foundation 4, INTERSWISS Immobilien AG, SIAT Immobilien AG and UBS (CH) Property Fund – Direct Green Property among them.[3]
43 new rental apartments
The new Sihlcity apartments at a glance
The most important facts known so far about the construction project.
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Apartments
43 rental apartments
A total of 43 new rental apartments are planned on the Sigma and Tau buildings.
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Apartment sizes
Mostly 3.5 rooms
The apartments are expected to measure around 54 to 146 m². The focus is on 3.5-room apartments.
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Outdoor spaces
Roof gardens & courtyards
Landscaped courtyards or private roof gardens are planned.
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Shared facilities
A shared piazza
A shared “piazza” is also planned for tenants.
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Price segment
Upper price segment
No specific rents have yet been published. Only the positioning in the “upper price segment” has been communicated.
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Schedule
Construction planned from 2028
Media reports mention 2028 as the planned construction start. No move-in date has yet been published.
Planning status: 26 August 2026
The planning and permit process may still change the project scope, execution and schedule.
Location
Kalanderplatz 2 in Zurich-Wiedikon
The building application was published for Kalanderplatz 2, 8045 Zurich. The site is located in District 3 and is assigned to zone Z6. The responsible authority is the City of Zurich's building permit office.[1]
The location is especially attractive for apartment seekers: Sihlcity combines homes with shopping, restaurants, a cinema, a hotel and services. Tram lines 5, 13 and 17 and the S4 Sihltal railway provide direct access to the site.[3]
Rental prices
Luxury apartments or upper price segment?
No specific rents have been published so far. The only confirmed information is that the homes are positioned in the upper price segment.
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Communicated
Upper price segment
Some media headlines refer to “luxury apartments”. However, the only substantiated statement so far comes from a UBS spokesperson, who said that the apartments would be priced in the upper price segment.[2]
distinctive rooftop location
complex construction
private outdoor areas planned
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Not yet known
No rental prices published
Specific net rents, ancillary costs and prices per square metre have not yet been published.
Any rent estimate today would therefore be speculative. The only thing clear is that the project has not been announced as affordable housing.
Permit process
Building application, not a final permit
The building application was published on 21 August 2026. The stated objection period ended on 10 September 2026. A published application means the project is undergoing approval; it does not guarantee that construction will proceed unchanged.[1]
Construction start in 2028 is a target
Objections, conditions, project changes, appeals, detailed planning and contracting can all affect the schedule.
Further development
Since
2023
Sihlcity is being developed in stages.
The 43 planned apartments are part of the long-term development of the site.
PrincipleRooftop extension instead of new land
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2023
Earlier phase approved
Zurich's building authority approved a two-storey extension of the Theta building with 21 small apartments and an extension of Sigma.
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28.08.2025
Administrative Court confirms development
The Administrative Court described the earlier project as the first of three stages in the site's ongoing development. The judgment is final.[5]
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Current project
43 additional apartments
The current application must not be treated as equivalent to the previously approved phase. It nevertheless shows that the densification of Sihlcity is part of a longer-term development.
Zurich housing market
What do 43 additional apartments mean for Zurich?
Every additional home matters in Zurich. However, the scale must be considered in the context of the entire housing market.
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252Vacant homes on 1 June 2026City of Zurich
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0.11%Vacancy rateextremely low vacancy rate
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246Vacant homes for rentout of 252 in total
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≈ 2,000homes come onto the market each monthaccording to the City of Zurich
43 apartments do not represent 17% of Zurich's market
Mathematically, 43 units correspond to around 17% of the 252 homes vacant on the reporting date. However, the City of Zurich explicitly points out that around 2,000 homes come onto the market each month and that the vacancy count is only a snapshot.[4]
From an urban-planning perspective, the project is especially interesting as infill development and rooftop extension: new homes would be created on an already intensively used site instead of undeveloped land.
Sihlcity today
100,000 m² of usable space and around 20,000 visitors per day
Sihlcity opened on 22 March 2007.[3]
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Housing
16 existing apartments
The existing apartments are expected to remain after the planned expansion.
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Area
approx. 100,000 m² usable space
The official centre website lists around 100,000 m² of usable space and approximately 98,000 m² of net lettable space.
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80 retail stores
A major retail destination within the city of Zurich.
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17 restaurants and food outlets
Restaurants and other food and drink outlets on site.
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132 hotel rooms
The existing hotel is also due to be expanded.
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18 cinema screens
The cinema is one of the centre's major leisure attractions.
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20,000 visitors a day
Approximate average daily visitor figure according to Sihlcity.
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2,300 jobs
The site is also a major employment centre.
Hotel
16 additional hotel apartments are also planned
In addition to the 43 new rental apartments, media reports say that the existing hotel will be expanded by 16 apartments.[2]
These hotel apartments are a separate part of the project and should not be added to the 43 apartments when discussing new conventional rental homes.
The 16 existing apartments at Sihlcity are expected to remain. The rest of the centre should also continue operating during the planned construction work.
Timeline
From2026
When could the new apartments be ready?
The project is still in the permit process.
Current statusNo move-in date announced yet
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21 August 2026
Building application published
Publication of the building application for Sigma and Tau with 43 apartments.
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10 September 2026
Published objection deadline
The objection period stated in the building application ended on that date.
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2028
Planned construction start
Media reports name 2028 as the planned construction start.
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Not yet known
Completion and first occupancy
No binding completion or first-occupancy date has been published yet.
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Not yet known
Initial letting
No public initial letting campaign for the 43 apartments has been announced yet.
Apartment search
When can you apply for a Sihlcity apartment?
There has not yet been an announcement of public initial letting for the 43 apartments. Interested people should not assume the apartments are already available.
It is worth monitoring new-build and first-occupancy listings in Zurich and creating search alerts early.
Sources
Sources and information date
The project information is based on the published building application, media reports and official information from Sihlcity, the City of Zurich and the Administrative Court.
Information current as of:
- BaugesucheSchweiz: Kalanderplatz 2 construction project, published 21 August 2026
- Tsüri: UBS plans 43 apartments on the roof of Sihlcity, 25 August 2026
- Sihlcity: facts and figures
- City of Zurich: 252 vacant homes in Zurich, 2026
- Zurich Administrative Court, VB.2024.00548, judgment of 28 August 2025
The project is still undergoing approval. Rents, completion and first letting information may change.
More on this topic
Related guides
01
Where 32,900 new rental apartments are planned
New rental developments in Switzerland and when they could be ready.
02
Guides to renting in Switzerland
How to find an apartment in Zurich in 2026 despite the extremely low vacancy rate.
03
30 minutes to Zurich main station
Where to find more affordable apartments around Zurich.
Direct answers
Frequently asked questions about the new Sihlcity apartments
The key answers in brief.
12Questions & answers
The building application published on 21 August 2026 lists 43 apartments on the Sigma and Tau buildings.
Two additional storeys are planned on Sigma and Tau. Media reports locate the apartments above the car park and on the part of the building along the Sihl.
According to published information, living areas will range from around 54 to 146 m². Most units are expected to have 3.5 rooms.
Specific rents have not yet been published. A UBS spokesperson described the apartments as being in the upper price segment.
No. As of 26 August 2026, a building application had been published. An application is not a final, legally binding building permit.
According to BaugesucheSchweiz, the objection period for the application at Kalanderplatz 2 ended on 10 September 2026.
Media reports mention 2028 as the planned construction start. No binding completion or move-in date has yet been published.
About half the homes should have a small landscaped courtyard, while the other half should have a private roof garden. A shared piazza is also planned.
According to published information, the 16 existing apartments will remain.
The existing hotel is due to be expanded separately by 16 apartments. These hotel apartments are not part of the 43 new rental apartments.
Under the plans communicated so far, the rest of the centre should continue operating during construction.
Zurich still has an exceptionally low vacancy rate. Forty-three additional homes matter locally, but will have only a limited effect on the tight citywide market.
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Key takeaways
Conclusion: 43 new apartments on an existing urban site
The 43 planned apartments at Sihlcity illustrate how Zurich can create additional housing through rooftop extensions and densification.
The location within the existing urban complex, private roof gardens or landscaped courtyards and the predominance of 3.5-room apartments are particularly noteworthy.
Apartment seekers will need patience: the project is still in the approval process. Construction is planned from 2028, while rents, completion and initial letting remain unknown.
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