We’re all familiar with the landscape of the City of London. But how does the architecture affect our surroundings? Join me on a virtual tour of London’s Square Mile, designed to highlight the impact of buildings on the urban environment.
This nearly 2-acre square provides a contrast with the walk to come, and highlights the importance of green space in the City. Grass helps moderate the surface temperature, while trees give shade and help screen out noise and pollutants. The openness, and the nature of the surfaces, mean the square will heat up and cool down more quickly than the surrounding areas, where energy will be needed to heat shaded areas and to cool areas where heat becomes trapped.
South Place and Ropemaker Street
We head down Moorgate and into South Place, where tall, glass-clad buildings and narrow medieval streets create an urban canyon. Across the junction in Ropemaker Street, a residential tower on the north side of the street will be in shade for much of the year. Its balconies, rather like the brise soleil shading on the office block opposite, are arguably redundant. Combine this with the impact of trapped heat and lack of ventilation, and there is likely to be a negative impact on both resource efficiency and the wellbeing of local residents and workers.
Each trading floor in this new ‘groundscraper’ is the size of a football pitch. Unlike the narrow buildings in South Place, it will be hard to adapt in future to accommodate new building technologies. Note, too, the shiny steel-plate surface reflecting heat back into the local environment, potentially adding to the cooling load of its neighbours.
Air flows freely and the sky above is open; this is a comfortable place to be. But take a few steps to the north and you’re hit by strong winds blowing around the base of Broadgate Tower. New developments are put through wind tunnel tests, but in practice it’s hard to predict the intensity of air flows on a neighbourhood scale.
Passing through Spitalfields, we arrive at the 230m Heron Tower. Light to the solar cells on its south side – currently supplying a small but significant percentage of the building’s energy needs – will be blocked once 100 Bishopsgate is complete. Buildings are not energy islands: they share space and passive and renewable resources with other buildings and spaces, and energy management strategies must take this into account.
The eastern cluster: the Cheesegrater, the Gherkin and the Lloyd’s Building Down
London Wall – where the curve of the street and varied height of the buildings create good airflow – we come out at the corner of St Mary Axe and Leadenhall Street where a tight cluster of tall buildings are creating a wide variety of effects at ground level. Today there’s a strong wind. Would that be acceptable if these were residential buildings? The developers have created a large open space here: but will anyone want to use it?
The narrow medieval streets behind the Lloyd’s Building lead us to 20 Fenchurch Street. In 2013, sunlight bouncing off the curved top generated enough heat to melt paint and plastic on nearby cars. The developers have since added a brise soleil to diffuse the light, but new reports suggest that the building is creating a downdraught strong enough to knock pedestrians off their feet. It’s a ‘selfish giant’ – highly energy efficient in its own right, but having a very significant impact on the surrounding area.
Walking down to the river, we see again how hard it is to predict climate impacts. Crossing Eastcheap, the wind was strong; a few metres further south, the air on Lower Thames Street was still. Across the river is The Shard which, despite its elegant shape, casts an enormous shadow, extending more than 350m in winter and plunging its neighbours into shade. Who is responsible for the resulting increase in energy needs? As development in London continues to gather pace, it seems to us that there is an urgent need for a framework that sets out clear parameters for planners and developers if we are to succeed in creating a truly resilient city.