City Hall by Foster + Partners: A Glass-clad Government Building

City Hall, designed by renowned architect Norman Foster and inaugurated by Queen Elizabeth II, is located in the Queen’s Walk, London on the south bank of the River Thames near Tower Bridge. The client, More London Development Ltd, appointed the project to the Foster group in the year 1998 and it was completed in the year 2002. It has been the headquarter of the Greater London Authority (GLA) since it opened, but under a lease of 25 years with a break after 20 years which is in December 2021. 

Design and Concept | City Hall

The City Hall has a surprising bulbous shape derived from a geometrically modified sphere using basic computer modelling techniques. The intention behind this form was to reduce its surface area, hence improving energy efficiency. 

This building breaks the conventional terms as it has no front or back. It is one of the capital’s most symbolically important projects, completely designed with a glass façade representing the transparency and accessibility of the democratic system. The architect Foster & Partners expresses it as a sustainable and virtually non-polluting public building. But its energy efficiency rating is ‘E’ with an annual CO2 emission of 2,255 tonnes of carbon. 

However, the design achieves optimum energy performance through its form receiving less solar energy. The exterior cladding of the building helps to balance the solar map which was produced by analyzing the sunlight patterns the whole year out. The building is designed in such a way that it leans back in the southern direction, shifting the plates step inwards which creates shading and naturally ventilated offices. 

The City Hall does not require chillers as it uses groundwater for the cooling system. The groundwater is pumped up via boreholes from the water table, and no additional heating. It conveys that it will use only a quarter of the energy consumed by a typical air-conditioned office building.

Architecture and Planning

The City Hall follows Neo- futurism style of architecture. It is a high-rise building with a height of 45 meters and a total of 10 levels above ground and 2 floors below it. A 500-meters long, helical walkway runs across the ten stories. This walkway provides the view of the interior of the building representing transparency. It is a highly public building bringing a mix of office buildings, shops, cafes, and landscaped public spaces.

The topmost level of the City Hall is an exhibition and meeting space with a wide viewing deck, known as “London’s Living room,” opened occasionally for the public. The assembly chamber located at the bottom of the helical staircase is facing north towards the Tower of London. It has 250-seat arranged in a circular form. This chamber is open for the public and is visible from the riverside and outdoor plaza. It is at the heart of the building as a showpiece above which the staircase starts.

There are two entrances for the public. They can enter either through the ground floor reception or from a large sunken amphitheatre. The amphitheatre leads to a public café at the lower level, paved with high-quality blue limestone. Moving forward, it opens in an elliptical exhibition space which is below the assembly chamber, and there is a 1:1250 scale model of the whole Central London from Hyde Park in the west to the Royal Docks in the east. This space is lightened by the daylight reflected by the ceiling pattern of concentric elliptical polished mirrors of stainless steel.

Structure and Construction | City Hall

Looking at the exterior of the City Hall, a striking glass and steel structure is seen on the south bank of the River Thames. The total cost of construction for this building was £43 million and it covers an area of 19,814m². It is constructed with composite structural materials. The site is a prominent landmark away from noise pollution. 

There were some mistakes in the design earlier like the roof vents which were controlled by weather sensors were left open during a storm, the glaze inside the office, and also the high humidity in summers and sudden cold in winters. Photovoltaic panels were installed afterward on the roof of the building which was used to produce energy. 

Foster and Partners explain that this installation completes the building as it was originally designed. The structural engineer of this project was Arup, and the landscape architect was Townshend Landscape Architects. And for services like lighting, the engineer was Claude Engle, and the quantity surveyor was Davis Langdon.

This onion-shaped building, as referred by Boris Johnson, has been through many ups and downs facing many comments but is unique. Its name is City Hall, yet it doesn’t serve the whole city of London (according to UK law). In December 2021, the Greater London Authority will vacate the building and move to a new assembly building in a shock plan to save £11m a year.

References | City Hall

• Foster (2019). City Hall | Foster + Partners. [online] Fosterandpartners.com. Available at: https://www.fosterandpartners.com/projects/city-hall/.
• STR Germany GmbH (2019). City Hall, London | 159693 | EMPORIS. [online] Emporis.com. Available at: https://www.emporis.com/buildings/159693/city-hall-london-united-kingdom [Accessed 5 Sep. 2021].
• Sadiq Khan proposes City Hall move to cut costs. (2020). BBC News. [online] 24 Jun. Available at: https://www.bbc.com/news/uk-england-london-53164416 [Accessed 5 Sep. 2021].
• Public building CO2 footprints revealed. (2008). The Guardian. [online] 2 Oct. Available at: https://www.theguardian.com/environment/gallery/2008/oct/02/energyefficiency.carbonemissions?intcmp=239#/?picture=338198107&index=5 [Accessed 5 Sep. 2021].
• Inside London’s new “glass egg.” (2002). news.bbc.co.uk. [online] 16 Jul. Available at: http://news.bbc.co.uk/2/hi/uk_news/2129199.stm [Accessed 5 Sep. 2021].
• Www-edie-net.cdn.ampproject.org. 2021. Solar panels to power London’s City Hall. [online] Available at: <https://www-edie-net.cdn.ampproject.org/v/s/www.edie.net/amp-news/2/Solar-panels-to-power-Londons-City-Hall/11996/?amp_js_v=a2&amp_gsa=1&usqp=mq331AQA#referrer=https%3A%2F%2Fwww.google.com&amp_tf=From%20%251%24s&ampshare=https%3A%2F%2Fwww.edie.net%2Fnews%2F2%2FSolar-panels-to-power-Londons-City-Hall%2F11996%2F> [Accessed 5 September 2021].
• Peracha, Q. (2020). Sadiq Khan announces plan to leave City Hall and move to East London. [online] MyLondon. Available at: https://www.mylondon.news/news/zone-1-news/sadiq-khan-announces-plan-leave-18479216 [Accessed 5 Sep. 2021].