Prime
Tower

At a glance

Switzerland's tallest building, 2011 to 2015

Swiss Prime Site developed the tower on the former Maag gear-factory site next to Bahnhof Hardbrücke. It opened fully let in December 2011 and is still the tallest building in Zürich.

Height

126 m

132.6 m to tip · highest occupied floor 118.7 m

Floors

36 + 2

36 above ground, 2 basement levels

Architects

Gigon/Guyer

Annette Gigon & Mike Guyer, Zürich

Completed

2011

Inaugurated 6 Dec 2011, fully let

Official height

126 m

Tallest building in Switzerland 2011–2015; still the tallest in Zürich

Floors above ground

36

Clouds restaurant on 35, conference centre on 34

Basement levels

2

Two-level underground garage

Gross floor area

53,461 m²

73,830 m² incl. Cubus and Diagonal annexes

Rentable area

≈ 40,000 m²

1,275 m² per storey, up to 4 tenants per floor

Workplaces

≈ 2,000

60–100 per floor; 3,500 across the whole Maag ensemble

Site area

9,800 m²

Former Maag gear factory site

Building volume

≈ 228,000 m³

Losinger quoted 280,000 m³ construction volume

Investment

CHF 355–380 M

Tower + Platform + Cubus + Diagonal

Elevators

9

6.5 m/s · top floor in about 30 s

Facade

≈ 20,500 m²

≈ 4,400 frameless, green-tinted triple-glazed elements

Concrete

36,000 m³

6,000 t reinforcing steel · 5-day cycle per floor

Certifications

LEED Gold

Core & Shell (70 pts) · Minergie · greenproperty

Owner

Swiss Prime Site

Developer and owner since 2004 (Maag Holding takeover)

Contractors

Losinger + Steiner

ARGE Prime Tower; Platform by HRS

Award

Gute Bauten 2011–15

Auszeichnung für gute Bauten der Stadt Zürich

Gigon/Guyer

Two rectangles, melted into a crystal

The architects won the invited competition in 2004 with a green-glass volume whose contours change with every viewpoint.

Timeline

1. 1913

   Max Maag moves Maag-Zahnräder to Hardstrasse 219; the gear works grow to 2,500 employees by 1980.

2. 1997

   Maag sells its manufacturing; the firm becomes a real-estate company on the former factory site.

3. 2004

   Swiss Prime Site acquires the Maag group (CHF 0.9 bn). Gigon/Guyer win the invited competition for the tower.

4. 2006

   A 126 m height profile (Baugespann) is erected with crane and helicopter for three months.

5. 2008

   18 Feb: demolition of the industrial buildings begins. 19 Nov: foundation stone laid.

6. 2010

   6 Apr: 105.5 m, overtaking Messeturm Basel. 21 May: core topped out at 126 m. 7 Jul: topping-out ceremony, 68 % pre-let.

7. 2011

   Summer: first tenants move in. 6 Dec: official inauguration, fully let. 12 Dec: Clouds opens on the 35th floor.

8. 2012

   2 Jan: the conference centre on the 34th floor opens.

9. 2015

   Roche Tower Bau 1 in Basel (178 m) takes the national height record; Prime Tower remains Zürich's tallest.

Drawings

Floor plans and sections

Gigon/Guyer publish the full plan set, and the letting agent's PDFs carry a metre scale bar. The drawings are copyrighted, so they are linked here rather than copied. The 3D model's footprint, height steps and cores were measured from them.

Who is inside

Law, banking, tech and a restaurant in the clouds

The tower was fully let at opening with about 26 tenants. Floor assignments come from press reports and company pages, so treat them as approximate. Toggle Tenants in the 3D model to see the stack.

Below the plaza

Two basement levels, one shared garage

The underground garage links the tower with Cubus, Diagonal and Platform. It is private, with monthly spaces rather than public hourly parking.

Maag-Areal

The tower and its three companions

Gigon/Guyer designed the ensemble as a family: the tower, the new Cubus, the refurbished Diagonal and the Platform built for EY.

Photographs

Emerald, white, and everything between

All images are freely licensed from Wikimedia Commons. Click any photo to enlarge; the caption links to the file page and licence.

Blue hour at the plaza entrance

Gostsens · CC BY-SA 4.0

From Bahnhof Hardbrücke

Hauserphoton · CC BY-SA 3.0

Evening light from Käferberg

Roland zh · CC BY-SA 3.0

Green glass against blue sky

Fred Romero from Paris, France · CC BY 2.0

Drone aerial over Zürich-West, 2023

Daniel Reust · CC BY-SA 4.0

Aerial view amid the railway yards, 2011

Hansueli Krapf  This file was uploaded with Commonist. · CC BY-SA 3.0

Lit upper floors against the Alps

kuhnmi · CC BY 2.0

Entrance canopy and lobby glow at night

FreeclimbZurich · CC BY-SA 4.0

Night view with Hardbrücke

FreeclimbZurich · CC BY-SA 4.0

Straight up the glass grid

Marius Haffner from Grenchen, Schweiz · CC BY-SA 2.0

Upper volumes and cantilevers, 2011

Roland zh · CC BY-SA 3.0

Reflected in the neighbouring facade

Wendelin Jacober · CC0

The Cubus annex with the tower behind

Gostsens · CC BY-SA 4.0

Framed by the railway viaduct

Tschubby · CC BY-SA 3.0

Snowfall on the Maag site, 2021

Thomas Woodtli from Zürich, Switzerland · CC BY-SA 2.0

From Maagplatz with the Cubus

Roy Egloff · CC BY-SA 4.0

View from the tower toward Uetliberg

Paebi · CC BY-SA 4.0

Sources

Where the numbers come from

• Gigon/Guyer – Prime Tower project page
• primetower.ch – official site (Swiss Prime Site / Wincasa)
• primetower.ch – tenant directory
• primetower.ch – the Maag site & annex buildings
• Swiss Prime Site – portfolio page
• Swiss Prime Site – topping-out press release, 7 Jul 2010 (PDF)
• Swiss Prime Site – Medienorientierung 6 Dec 2011 (PDF)
• CTBUH Skyscraper Center – Prime Tower
• Architectural Record – Prime Tower
• Baunetz Wissen – Prime Tower in Zürich
• Walt Galmarini – structural engineering
• Wikipedia (EN) – Prime Tower
• Wikipedia (DE) – Prime Tower
• Bilanz – Prime Tower zieht neue Mieter an (Jan 2022)
• Clouds – restaurant, bar & conference
• Historisches Lexikon der Schweiz – Maag

This is an independent showcase and is not affiliated with Swiss Prime Site, Wincasa or Gigon/Guyer. The 3D model is a stylised reconstruction: footprint and height steps follow the published plans, but details are approximate. Map data © OpenStreetMap contributors.