They’re shooting up all over the country, but are these verdant facades just a gimmick or a sustainable solution with staying power?
Green roofs are a proven feature in the lexicon of sustainable architecture, but now architects are planting the walls of buildings with foliage as well. In urban centres from Tokyo to Paris, sprouting facades are taking root in the streetscapes and although Britain has been slow on the uptake – the Japanese have been raving about them for the past five years – living walls have finally arrived. So how do they work? What are the environmental benefits? And is this really a trend that is set to be a milestone in our race to create more sustainable buildings?
The most high-profile living walls are those created by the French horticulturalist Patrick Blanc (verticalgardenpatrickblanc.com). Most recently he has created ‘vertical gardens’ for architect Jean Nouvel’s Musée du quai Branly in Paris and Herzog & de Meuron’s CaixaForum in Madrid. The British, too, are drawing on Blanc’s experience. FAT, for example, is currently applying for planning permission to use the system for The Belvedere, a 19-storey, mixed- use tower block with a living facade in London’s Mile End.
Blanc’s vertical garden is composed of three parts: a metal frame, a PVC layer and a layer of felt. The metal frame can be hung on a wall or can be self-standing and provides an insulating air layer. A PVC sheet is riveted to the metal frame, making the installation rigid and waterproof. Finally, a felt layer made from polyamide is stapled to the PVC. This felt is resilient against rot and its capillary-like make-up allows water to travel through the material, feeding plants growing from its surface. Plants are installed on the felt as seeds, cuttings or already grown plants, and water supplemented with nutrients is automatically dripped through the felt from a punctured hose that runs along the top of the installation. The total weight is around 30kg per sqm, allowing vertical gardens to be installed on even very tall buildings, but Blanc’s systems are pricey. For large spaces, the cost is roughly £475 per sqm, plus labour. For a smaller area of 40sqm the cost increases to approximately £945 per sqm, as smaller spaces are more complex.
At Eco Age (020 8995 7611; eco-age.com) – a sustainable retailstore and consultancy service on Chiswick High Road in London – one facade of the renovated building is coated in a forest of ferns. The installation was created using the modular Canadian ELT system (elteasygreen.com), which consists of black plastic panels, measuring 50x50cm, filled with 50 small pots, each individually planted with foliage. These panels are then screwed into a plywood structure built to allow an air gap between the existing walls of the building and fed by an automated water pipe that zigzags though the panels and is connected to the mains. The 60sqm wall took two and a half days to install, with each panel costing £70, which is roughly 30 per cent of the cost per sqm of the system created by Patrick Blanc. ‘What’s good about the system is that it’s modular, so if anything goes wrong and plants start to die, you can just replace single panels rather than the entire installation,’ says the CEO of Eco Age, Nicola Giuggioli.
Bespoke systems are also a possibility. Ben Addy, founder of Moxon Architects (020 7034 0088; moxonarchitects.com), has designed a wall of foliage for a rear addition to a house in Barnes, west London (pictured and overleaf). Rather than grow the plants from the wall, Addy has constructed a band of lattice steelwork offset from the wall of the new extension. Foliage, planted in 150 / GRAND DESIGNS / NOVEMBER 2008 soil beds at the base of the lattice and built along the roof, is then grown up and around the steel structure. It’s an economical and simple way to create a regenerating brise soleil, which protects the building from excessive solar gain.
While it remains to be seen whether living walls will continue to adorn high-profile projects where architects are more likely to be searching for fresh approaches to distinguish their buildings from existing work, the environmental benefits are impressive. Like green roofs, living walls increase biodiversity and provide much-yearned-for contact between urbanites and nature. They also help decrease the urban island effect, limit water run-off, help to purify the air and also reduce the energy demands of the buildings they cover by providing thermal and acoustic insulation. A sound investment, then, on sustainability grounds.
So far, gaining planning consent has not been a problem for Giuggioli and he’s confident that the market for residential buildings will continue to swell. ‘We are getting a lot of enquiries,’ he says. ‘We’re currently installing a living wall on the side of a terraced house and on the walls that surround a client’s garden.’
Both Addy and Giuggioli point out the aesthetic benefits that foliage can bring. Working with a horticulturalist, Addy has selected plants that change throughout the year. ‘The different species of plants are specifically selected to “program” the building as a seasonally developing spectacle of colour and texture,’ he says. In this vein, living walls could be used not only to create better looking new-builds, they could also be an effective means of improving both the environmental performance, and the aesthetic appearance of some of Britain’s poorly executed building stock. ‘The sustainability argument for green walls is a consideration, but for us the more important fact is that they can be extremely attractive and architecturally versatile,’ says Addy.
In many ways, Britain is a fertile breeding ground for living walls. The mild, damp climate is perfectly suited to this technique. Plus, unlike many green gizmos, foliage-covered walls are already a common feature of our architectural landscape. ‘The notion of “Arcadia” is a part of our country’s psyche and green walls – whether ivy-clad vernacular or more sophisticated contemporary techniques – are an intriguing possibility that, in one form or another, have been with us for some time,’ says Addy. With new techniques making living walls more versatile and sustainable than ever before, the trend for sprouting facades look set to grow.