Green wall

Green Wall at Queen's University, Kingston, Ontario, Canada by Nedlaw Living Walls

Green wall by bitter melon shading sunlight and keep room rather cool in summer. Energy conservation for airconditioning, Primary school in Itabashi, Tokyo

A green wall is a wall, either free-standing or part of a building, that is partially or completely covered with vegetation and, in some cases, soil or an inorganic growing medium. The vegetation for a green façade is always attached on outside walls; with living walls this is also usually the case, aldough some living walls can also be green walls for interior use. . The latter however does not provide such rigorous cooling or air filtering benefits. They are also referred to as living walls, biowalls, or vertical gardens.

Types

There are two main categories of green walls: green façades and living walls. Green façades are made up of climbing plants either growing directly on a wall or, more recently, specially designed supporting structures. The plant shoot system grows up the side of the building while being rooted to the ground. In a living wall the modular panels are often comprised of polypropylene plastic containers, geotextiles, irrigation systems, a growing medium and vegetation.

Living walls can be further broken down into passive and active systems.'Active living walls' are a new, concept in which the living wall is integrated into a building's air circulation system [1]. Active living walls are based upon the sciences of biofiltration and phytoremediation. According to a study done at the University of Waterloo, "Living walls with biofilters increase the capacity of air filtration." The Active Living Wall harnesses nature's cleansing power by drawing air through the root system of the wall. Beneficial microbes actively degrade the pollutants in the air before returning the new, fresh air back to the buildings interior . Passive living walls do not have any means of moving the air into the root system where most of the degradation of pollutants occur. The impact of passive systems on air quality are scientifically questionable. .

Some active walls are kept behind glass to ensure more predictable airflow than can be achieved with inactive walls, which have no mechanized air circulation. Instead, they are kept open to promote as much free air circulation as possible.

Function

Green walls are found most often in urban environments where the plants reduce overall temperatures of the building which in turn reduces energy consumption. "The primary cause of heat build-up in cities is insulation, the absorption of solar radiation by roads and buildings in the city and the storage of this heat in the building material and its subsequent re-radiation. Plant surfaces however, as a result of transpiration, do not rise more than 4–5 °C above the ambient and are sometimes cooler."

Living walls may also be a means for water reuse. The plants may purify slightly polluted water (such as greywater) by absorbing the dissolved nutrients. Bacteria mineralize the organic components to make them available to the plants.

Living walls are particularly suitable for cities, as they allow good use of available vertical surface areas. They are also suitable in arid areas, as the circulating water on a vertical wall is less likely to evaporate than in horizontal gardens.

The living wall could also function for urban agriculture or urban gardening. It may be built as a work of art for its beauty. It is sometimes built indoors to help cure sick building syndrome.

Green façades

Some popular plants (for temperate climates) include:

• Actinidia
• Akebia quinata/trifoliata
• Aristolochia
• Campsis
• Celastrus
• Clematis
• Cotoneaster
• Euonymus fortunei
• Hedera
• Humulus lupulus
• Hydrangea petiolaris
• Lonicera
• Parthenocissus tricuspidata/quinquefolia/inserta
• Vitis berlandieri / riparia
• Polygonum auberti
• Pyracantha
• Wisteria

Living wall kit systems

Since the creation of the living wall, several kits have come unto the market to ensure rapid set-up. Notable exterior wall kits are:

• the Parabienta Green Wall
• the Copijn WonderWall
• Patrick Blanc's green wall system
• the Fytowall system

Notable interior wall kits are:

• the Wonderwall

See also

• Biofiltration
• Green roof
• Folkewall
• The Hanging Gardens of Babylon
• Gwang Gyo Power Centre
• Timelinks Ziggurat
• Hydroponics
• Musée du Quai Branly
• Roof garden

External links

• Living wall at University of Guelph-Humber wins RAIC award
• Vertical and verdant, living wall systems sprout on two buildings, in Paris and Vancouver, Architectural Record
• Vertical Garden, Green Wall and Living Wall information