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CORPUS Magazine

Living walls

Architects and designers of vertical gardens create biospheric artworks in places where there isn’t really any space for greenery in classic architecture. They bring the facades of high-rise buildings to life, as well as the interior walls of commercial buildings. For an extra swathe of the natural environment in the urban setting.

The air is cool and clear, climbing plants frame the windows of the 46th floor, and neighboring city dwellers seeing the totally greened façade feel a strong affinity with nature. This scenario may sound utopian, but it reflects the yearning of many town inhabitants for more greenery – and is already becoming reality in a number of urban construction projects. This scenario may sound utopian, but it reflects the yearning of many town inhabitants for more greenery – and is already becoming reality in a number of urban construction projects. Space in cities is in increasingly short supply and any vacant plots are jealously guarded for building development. And this is why the subsequent integration of parks and gardens is rarely possible. So what’s the solution? Urban planners, plant researchers and architects have found an answer in “vertical gardening”.

1: Vertical gardens not only enliven building facades, they also noticeably enhance indoor climate.
2: The composition of plants can be assorted to the client’s idea, while the local climate is always the determining factor.


Patrick Blanc, French botanist and garden architect, is considered the inventor of the vertical garden. For him, this special form of greening not only enriches urban quality of life, but also serves as a natural purification system for towns. Plants absorb carbon dioxide, release oxygen, humidify the air and filter out contaminants. So what not exploit these positive features in buil­ding design? The French architect Jean Nouvel, for example, has raised residential quality in high-rise buildings to a new level in his One Central Park project in Sydney. One of the world’s largest vertical gardens, with a surface area of over 1000 square meters and over 35 plant species, embellishes the facade of the two 87 and 110 meter high apartment and commercial towers. The green wall designed by Patrick Blanc contributes to the building’s high energy efficiency thanks to its natural insulation properties. In addition, a cantilever­ed mirror construction reflects the sunlight, guiding sufficient daylight into the lower stories. The motor-driven mirrors also provide the ad­joining garden with sufficient light.

In their joint projects, Nouvel and Blanc repeatedly exploit the synergies of architecture and botany. A spectacular prospect are the Le Nouvel twin towers in downtown Kuala Lumpur still under construction. A vertical garden on the facade will span 43 and 49 stories respectively. Against the backdrop of the increasing expulsion of nature from the city in the face of advan­cing urbanization, the vertical gardener is now creating a new, small eco-system in the center of the million-strong city.

A vertical garden is like a shop window, where all the plants are clearly visible. It’s quite different when you see a horizontal garden where everything is a matter of perspective.

Patrick Blanc

Depending on the prevailing conditions, vertical gardens are capable of thriving without much water, as the KAFD Conference Center in Riyadh shows. The architects Skidmore, Owings & Merrill LLP (SOM) have designed the center as an architectural extension of the surrounding desert landscape. The building in the King Abdullah Financial District stands out not only with its faceted facade. Local desert plants on the outer walls and roof enhance the building’s futuristic appearance and underscore the oasis-like nature of the complex in the heart of the Saudi Arabian capital domina­t­ed by concrete and enclosed by desert.

Greened facades not only add an extra esthetic dimension, but can also modify a building’s thermal behavior.
Designers of living walls are fascinated by plants’ ability to thrive even without soil.
The Le Nouvel twin towers with their living walls are going up opposite Kuala Lumpur’s well-known Petronas Towers.

The founders of the Canadian company Green over Grey have also considered the effects of plants on the climate in enclosed rooms and successfully applied the principle of the vertical garden indoors in their “living walls”. In an office building in Lévis, Canada, they have planted the world’s biggest greened interior wall with a height of 65 meters. The idea of cladding house facades, bridges or walls with plants is not in itself new, but requires special methods when implemented on a large scale. When ivy or Virginia creeper grows up a wall in the classic manner, the masonry always serves as the load-bearing element – a challenge in terms of long-term strength. However, this kind of greening is of no interest in any case for buildings more than eight stories high, as ivy’s growing height, like that of trees and other plants, is limited and rarely exceeds thirty meters.

Sandstorms and temperatures of around 50 °C won’t bother the plants on the KAFD Conference Center in Riyadh.
The plants used by Patrick Blanc are selected to suit the climate zone and the position on the building.

The principle of the vertical garden is deceptively simple:
Using the method developed by Patrick Blanc, 1 centimeter thick PVC panels are riveted to a standing or hanging metal frame and covered with synthetic felt. Such constructions of any size can be attached to facades at any height. According to Blanc, a vertical garden inclusive of its frame weighs less than 30 kilograms per square meter. If a small gap is left between the plants and the wall of the building, the static layer of air in between acts as an insulator. If the vegetation grows on the wall itself, the plants and the substrate provide the insulation. The roots of the plants burrow into the felt, with nature serving as a model: Plants do not necessarily need earth, and many grow on tree bark, rocks or moss. What all plants have in common is their need for water and light, albeit to varying extents. The vertical garden is irrigated usually from the top, ideally with recycled waste water or rainwater. Plants are chosen not only for their visual properties, but also according to the light conditions on the building: north or south wall, strong sunlight or shade. The outcome is a suspended, self-contained eco-system that emits oxygen, cools the air in summer, insulates the building against the cold in winter, and brings nature a step closer to people in cities. I t creates habitats for wildlife, improves the microclimate, filters out noise and dust in the building’s immediate surroundings, and enhances biodiversity overall – particularly in urban environments. Greened facades are still regarded more as project art by the public and less as a functional design feature. But their potential is being increasingly recognized and exploited. The cities ass over the world continue to grow – above all upward because of shortage of space. If the resultant gigantic facade surfaces are converted into vertical gardens, natural greenery in the urban environment need be a utopian dream no longer.

The KAFD Conference Center is designed as an architectural extension of the surrounding desert landscape.

Architects and designers “Green over Grey” design living walls and convert grey facades into living art­works. With their 65-meter-high indoor wall call­ed “The Currents” in Lévis, Canada, the wall artists op­erating mainly in Canada and the USA have executed a showcase project that sets not only esthetic standards in wall greening.

In conversation with CORPUS, founder Patrick Poiraud explains what makes vertical gardens in interiors special and the effect they have on the atmosphere and people.

CORPUS: Mr Poiraud, you describe the name green over grey to be programmatic – when did you start working with plants?

PATRICK POIRAUD: I have always been fascinated with plants, and my interest in living walls started when I was around eight years old after I first saw a vertical garden installation in Paris. My passion only grew from there. Green over Grey started officially as a business in 2008 but it was a few years before that when we started researching various technologies and studying in depth how plants grew vertically in nature.

CORPUS: What kind of challenges came up while working on “The Currents“?

PATRICK POIRAUD: The biggest challenge about ‘The Currents’ was the access as it is the tallest indoor vertical garden in the world. A living wall typically requires access for maintenance on a monthly basis so it is important that a proper system is devised from the beginning. This was accomplished by the general contractor installing a metal beam that a lift is attached to. Then every portion of the wall was accessible.

CORPUS: What is different working on an indoor living wall instead of an outdoor one?

PATRICK POIRAUD: Indoor walls are nice in the fact that you can control the environment, like lighting or temperature. However, in Canada especially the types of indoor or tropical plants that are available can be somewhat limited to a few hundred, whereas for outdoor walls there are literally thousands of plants to choose from. Outdoor walls are designed according to the exposure; a south facing wall will have completely different plants than a north facing wall.

CORPUS: How does a Living wall affect or change a room or do Living walls have effects for example for the room climate or the people surrounded by it? Are there any measurements or statistics concerning this topic?

PATRICK POIRAUD: An indoor wall will add a few percent of relative humidity to a room. Typically this is very beneficial to the dry environments that are found indoors. Sometimes you can find 25 percent of relative humidity, which is comparable to the Sahara Desert. Proven by the NASA is the fact that the plants also add oxygen and remove common indoor air pollutants. There have been studies that have proven that people living and working around plants are happier and more efficient. Also studies in hospitals have shown that patients with a view of greenery get better faster and take less medication than those without.

The world’s biggest greened interior wall is 65 metres high – and clearly visible from the outside.

CORPUS: Could you describe for us what your clients are expecting from the Living walls? Do they express particular hopes in your work?

PATRICK POIRAUD: The main benefit to our clients we find is the overall improvement of aesthetics. Typically living walls are put in to beautify the space. Then there are of course the other benefits listed. Living walls are also not static and are constantly changing and growing which is quite different than a piece of art that always stays the same and might become outdated.

CORPUS: How is a living wall created? What does your design and construction process look like?

PATRICK POIRAUD: When designing a living wall we first discuss with the client their desires. This involves asking if they want a more colorful wall or one with just shades of green, abstract art or patches, flowers or fruit and which textures are preferred and what they like to be the overall depth – it can vary from a few centimeters to a meter or more. After that we come up with a design package, our planting map and finally install the materials, automatic irrigation and plants.

CORPUS: For your projects you are using eco friendly panels. What significance does sustainability have in your work?

PATRICK POIRAUD: Of course when we were developing our “green wall” system we wanted it to be as green as possible. There are other companies that use unsustainable, high energy consumption and even toxic materials. It was extremely important to us that we use 100% recycled and non-toxic materials. This is also expected from our clients and we feel we have perfected our product in this sense. Another part of the sustaina­bility aspect is bring nature back into urban environments. When designing our walls we aim to make them as biologically diverse as possible and include many native and locally adapted plants that will benefit the local fauna as well as the people that live there.

CORPUS: Mr Poiraud, many thanks for this interview.

Biography in brief 
Patrick Poiraud has set himself the goal of integrating plants better into our urban world in order to bring natural greenery into cities. Having grown up in the country and later in Paris, the native Frenchman moved to Sweden where he worked for several different companies. After over ten years, Poiraud finally decided to make his passion his profession – and started over again in Canada. Teaming up with Mike Weinmaster, environmental scientist and engineer for sustainable infrastructure, he founded “Green over Grey” in 2008. On numerous trips to the Amazon basin and Australia and as far as Laos, Poiraud has deepened his knowledge of plants and their habitats.

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