Green Innovation: Living Walls and Roofs
Our understanding of climate change is deepening by the day and as a result, architects and structural engineers are now routinely incorporating living, organic walls and roofs into their building designs. This positive trend of using of ‘horti-construction’ techniques that combine traditional building methods with the innovative use of vegetation looks set to grow.
Living walls and roofs are becoming increasingly popular as buildings in heavily populated areas around the world become one with nature and embrace the most natural green technology of all - organic, living surfaces. After all, what could be more eco-friendly than self sufficient, vertical gardens attached to the exterior or interior of a building?
There's a number of benefits to this fast growing trend: We all benefit from cleaner city air; buildings are cooled naturally and energy savings ensue; wildlife survives and thrives thanks to new habitats, the urban bee population gets chance to recover; grey water can be purified by absorbing dissolved nutrients from vegetation; carbon is offset by sustainable architecture; not to mention the simple fact that aesthetically we'd all prefer lush, green plant life to cold, sterile walls of glass and steel.
A World of Opportunity
Hanging gardens such as those that adorn Vo Trong Nghia’s Babylon Hotel on the Vietnamese coastline are a perfect example of how living walls are taking the hospitality industry to ever more eco-friendly heights. Providing long-stay guests with a unique experience centred around reconnecting with nature, these innovative facades make this aptly named hotel a superb example of how to fuse stylish luxury with eco values seamlessly.
"The green layer provides a visual barrier that creates the separation from the road to enhance the privacy of the resort," the architects explained. "The finishing material keeping its natural appearance of its base achieves effeminacy and harmony with the surrounding nature."
In Copenhagen, Denmark, an inspired multi-storey car park utilises green living walls to hide the vehicles from the outside world. So while the cars themselves are obscured from view, the air purifying greenery also helps to erase the environmental impact of those vehicles at the same time.
Countless other examples of living walls and roofs are popping up all over the globe. And as the trend grows, so must engineers understanding of how to build structures that can sustain several tonnes of vegetation without compromising the building's underlying structural integrity. As of 2015, the largest green wall covers an incredible 2,700 square metres (29,063 square feet - or more than half an acre) and is located at the Los Cabos International Convention Center in Mexico.
Living Proof: George Carey Primary School
Living walls and roofs are also growing in popularity in the UK, with the George Carey Church of England Primary School standing out as a pioneering example. The building's living roof space is a feature at the community campus, which was created as part of the first phase of the £130 million Barking Riverside development.
To support the living roof, CCL designed and installed a post tensioned concrete slab measuring 2500m2. The slab was engineered to include lots of openings for roof lights, ventilation towers, ductwork and external mechanical equipment. As these openings were arranged in a complex and irregular pattern, reinforced concrete, the originally specified material, was not suitable and CCL were asked to solve the problem with post tensioning technology instead. The living roof was designed to also incorporate integrally waterproof concrete rather than the industry standard applied sheeting or coating.
A Blossoming Construction Phenomenon
Although patented in 1938 by Professor Stanley Hart White, living walls and roofs have only become a common consideration for architects and structural engineers in recent years. Indeed, of the 61 large-scale outdoor green walls listed in an online database provided by greenroof.com, 80% were constructed in or after 2009 and 93% dated from no later than 2007.
However, given its wide aesthetic appeal and ecological benefits, we can be confident that the popularity of living walls and roofs is set to continue growing.