‘Living walls’, green façades, vertical farming or roof gardens are increasingly featuring in the design-concept of buildings.
Most of the time viewed as an architectural feature or ‘architectural window dressing’, they also offer benefits that are very often undervalued, according to an Arup report.
The ‘Cities Alive: Green Building Envelope’ report, the fourth report in the ‘Cities Alive’ series, quantifies the benefits of green building envelopes, roof gardens and urban farming by looking at green infrastructure schemes in five global cities — London, Los Angeles, Berlin, Melbourne and Hong Kong.
In increasingly populated cities — 66% of the population is expected to live in urban areas by 2050, according to a United Nations report — where the space for ‘green infrastructure’ is being reduced, buildings are becoming a way of introducing green into cities.
Tom Armour, global landscape architecture leader at Arup and one of the report’s contributors, says: “We were gathering global research information from around the world to reach conclusions about the positive contribution that buildings can make to healthier cities.”
According to the report, the urban nature has become vital in tackling some of the cities’ growing problems — in a world currently affected by global warming and climate change.
“If we can build nature into our urban systems, we can actually create healthier cities for people,” says Armour.
He adds: “Buildings can play an important role, because buildings have surface area, roofs, walls and space. Buildings are huge components of cities and they can help build up healthier places by integrating green and helping with the dust, air pollution, storm water, and creating places where people want to be.”
The report highlights the positive impact of green envelopes, roof gardens and vertical farming in tackling issues that are prejudicial to people’s wellbeing and health, such as high air pollution, urban heat and noise levels.
Researchers have found that these green features when introduced into urban spaces are able to reduce air pollution by up to 20% in some locations.
Armour says: “Tackling rising air pollution is a priority to help improve people’s health. As our cities continue to become built up, ‘grey’ structures, such as walls and roofs, are a source of untapped potential for adapting into green spaces.”
He adds: “When well-designed, green envelopes can have a positive impact on tackling air pollution, but can also deliver a wide range of social, economic and environmental benefits to make cities more attractive and healthier places to be.”
Cities are then encouraged to turn green as a way of ‘fighting’ toxic air — in 2012, 7M of people died due to poor air quality, according to the World Health Organisation.
The report has also stated their ability to reduce the urban noise level by up to 10 decibels.
Armour says: “It may not have a noticeable impact if some of the environments are dominated by sound sources, but it will have a greater impact during the night, because the vegetation can absorb a lot of noise.”
Additionally, green on buildings can reduce urban heat by up to 10°C and peak energy consumption in traditional buildings by up to 8%.
He adds: “There are also benefits in terms of water management as green on buildings can slow down storm water, and it can temporarily store water.”
The benefits of green envelopes and roof gardens are remarkable, but the most important thing for Armour is people’s health and wellbeing.
“I think the real focus of the report was to look at the really positive link between the natural environment and people’s wellbeing and health,” says Armour.
He adds: “What this research is telling us overwhelmingly is that urban green has a fundamental role in making conditions better for people.
“People need to have daily contact with nature. This connection with nature is right at the core of our identity as a species and therefore our wellbeing. If we introduce more green in and around buildings then you are creating a definite benefit for people.”
Vertical and urban farming also have a positive role to play in cities, according to the report, in creating community spaces and help with social interaction.
“Green can provide space for urban agriculture, for growing food, and this has a social benefit. You grow food and have farms on top of buildings and people gather, and meet and talk and socially interact which is always good,” says Armour.
The Triton Street Green Roof in Regents Place, London, was designed by Arup and comprises three green roofs — covering an area of 2,500sq m.
It might seem a no-brainer, then, that everyone should start constructing and incorporating nature into their own buildings and projects. But there are a few challenges raising doubts in people’s minds, says Armour.
“I think the challenges often stem from people’s fear of the projects going wrong, but I think that our technology has really moved on now and we have much better materials and systems,” says Armour.
Maintenance has also been pointed out as a disadvantage for those thinking of building the ‘living walls’.
“There might need to be some special maintenance requirements, but this could be dealt with easily,” says Armour. “There’s nothing particularly special that we don’t have the technology to deal with. Because they are giving us benefits we shouldn’t think twice about needing to maintain it. The benefits far outweigh the negatives.”
The report is explicit: ‘living walls’, urban farming and roof gardens create better places for people to live, work and visit — besides creating a cleaner and healthier environment. Even though there is still a long way to go until all cities turn green, if this will ever happen, Armour is certain of one thing: people “will be much happier by being in daily contact with green.”
* Images: Arup