Are Living Walls The Key To Cooler Cities?

Whoever said the living was easy in summertime never lived in a city between the months of June and August.

Of course, higher temperatures in urban areas are nothing new, but the summer of 2021 has already proved to be a particularly sticky one with heatwave warnings in Japan, California and England. 

The threat of global warming could see temperatures rise even further and as people try to return to work in major cities, the question remains what can be done to ensure they remain as cool as possible. 

But before everyone reaches for the air conditioning dial, there are alternatives. 

Living walls – sometimes referred to as green walls – can help cool both the interior and exterior of buildings, as well as improve air quality and absorb sound in city centres.

They can also improve the aesthetics of drab office blocks, so why are they not more popular?

Internationally renowned landscape and garden designer Andy Sturgeon said recent reports suggest that living walls can insulate a building to great effect and keep it in excess of 1 degree centigrade warmer in winter and 1 degree cooler in summer.

“When green walls first appeared there were some notable failures as you might expect with a new technology and clients became aware that there was a risk and a cost associated with them,” said Mr Sturgeon. 

“Architects liked the idea in principle, but a living thing can’t be applied to a building like an inert cladding, it is not static and it has to be maintained. 

“I would say that green walls have now finally taken off as landscape architects, architects and installers understand them more and work together to use them to great effect. The plant choices are better and there are some excellent examples around the world,” he added.

“Many cities including London and Singapore now encourage green walls through their planning policies and this is already having a significant impact.”

Siân Moxon, a Senior Lecturer in sustainable design and Researcher in urban biodiversity at London Metropolitan University says living walls can also mitigate environmental problems that are particular to cities, such as flooding and overheating caused by a prevalence of hard surfaces, air pollution, and poor access to nature. 

“Their planting helps to cool building interiors and streets through shading, insulation and evapo-transpiration,” says Ms Moxon. 

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