Green Facades

 (Fig. 1.1 Green facade)

Living walls are also known as green-, bio-, vegetated-, living- or eco-walls and as vertical garden. At their simplest, they are vertical gardens and can include any type of vegetative covering of a standard wall, such as hanging gardens and climbing vines. 

There a few ways that plants can grow on vertical surfaces: the first is by affixing multiple rows of small planters to a vertical wall; the second is by affixing felt fabric to a wall, and sticking plants into pockets within that felt fabric. The second kind of living wall is more aesthetically appealing, and allows for plant varieties with more extensive root systems. 

(Fig. 1.2 living wall systems)

The third system is the use of planter boxes which can be planted on balcony edges and balustrading or on a ledge with access space. Trellis are then erected between the boxes on which the plants will grow and cover the whole facade of the building. This method will also act as a filter for direct sun light entering the buildings.

 (Fig. 1.3  Musee du Quai Branly in Paris)

In these latter systems, plants typically grow without soil between layers of fibrous material (such as felt or plastic mesh), or in pre-vegetated panels, that are suspended in front of a building wall. They are planted in the ground or in planter boxes. Based on the principles of hydroponics, water, with added nutrients, drips slowly to the bottom of the wall where any excess is pumped up and re-circulated. Some living walls incorporate a pool at the base of the structure which can include fish and small animals such as amphibians.

Structural weight, moisture retention, nutrient supply and water distribution are important design considerations in all living walls.

 (Fig. 1.4  Modular planted panels)

(Fig. 1.5  Concorcio building concept sketch)

Types of living walls

Green facades

These commonly feature vertical structural systems that support climbing plants on the building exterior. The vines and climber type plants are supported by stainless steel cables, mesh or metal grids and grow up from grade or planter boxes.

 (Fig. 1.6  Modular planted panels)

(Fig. 1.7  Modular planted panels)

Active walls

These are indoor features joined to the building’s air circulation system where fans draw air through the living wall before being circulated through the building to cool down and humidify the air, increase the oxygen levels and reduce pollutant levels.

 (Fig. 1.8  Potted systems) 

  

 (Fig. 1.9  Potted systems) 

Inactive walls

These types pf walls are also indoor features, but rely on passive open design for free air circulation rather than on mechanical air systems.

Outdoor Living Walls

Outdoor living walls are the engineered building envelope systems that allow a organic sun screen, a layer of living plant material to be suspended at some distance from the outside wall of a building (Fig. 1.9)

Specialized membranes and drainage layers support the growth of a range of mosses, vines and perennial plants. 

 (Fig. 1.10  Planter box)

Advantages

Depending on the system used, living walls provide shade for buildings, blocking the direct sunlight from entering, or in the case of the modular systems  they add thermal mass to a building. The vegetation will also lower air temperatures by evaporating enormous amounts of water from leaf surfaces, thereby moderating indoor and outdoor building temperatures.

Studies have found that the reduction of summer cooling loads by living walls are more dramatic than that for green roofs. The same study showed that significant reductions in the urban heat island effect could be attained if living wall technology was used extensively.

 (Fig. 1.11  Planter box)

Furthermore, the sound transmission into buildings are reduced due to the layer of plants, growing medium and, depending upon the design, the dead air space between the living and conventional walls. 

 (Fig. 1.12 Modular fibrous felt material)

  (Fig. 1.13 Modular planted panels)

Negative Aspects

Indoor projects will require monthly maintenance programs similar to other indoor garden requirements. For obvious reasons, the vegetated walls require an even higher level of maintenance than climbers on a vertical frame.

From a practical point of view, the sheer height of some outdoor living walls will likely pose challenges in terms of maintenance access.

Ii term of energy consumption, the more complicated engineered irrigation systems for the indoor living walls have been criticized for using too much electricity to supply light and pump water and nutrients through the system, and for using embodied energy in the building components.

However, it does not appear that a cost-benefit analysis has been done to clearly assess how effectively living walls achieve their various goals (including stormwater volume attenuation and cleansing) and at what price.

Proper air flow and water movement must be established to help ensure harmful moulds do not grow, particularly in indoor applications. In addition, the constant presence of moisture means that the walls must be well separated from the adjacent structure.

Designers should consider pollen generation when choosing plants, especially for indoor applications or beside operating windows.

(Fig. 1.14  irrigation system)

(Fig. 1.15  Module installation 3D)

 

 

And they all lived happily ever after...

 

THE END