Types and Components of a Green Wall

A green wall is a general term given to a vertical wall that is covered in vegetation. Based on how this vegetation is grown on the vertical system, they are classified into two main types. 

Green Wall - Green Façade

They are:

1. Green facades
2. Living Walls

The general classification of green walls and their respective examples are given in the flowchart below.

Types of Green Walls

1. Green Facades

Green facades can be direct or indirect facades. In direct green facades, the vegetation is rooted in the ground and it grows vertically on the walls. In indirect green facades, the climbing plants grow vertically on the trellises, cables, or mesh support system, without attaching to the surface of the building.  

Types of Green Facades

2. Living Walls

A living wall is a building envelope system, where the plants are planted and irrigated on a structure that is attached to the wall without relying on a ground-level root media. Living walls with planter boxes, hydroponic systems, modular boxes, felt pockets, etc. are some examples of living walls. 

Living Wall

Components of Green Walls

The installation of green facades is less complicated compared to the living wall system. But compared to facades, living walls provide environmental and social benefits immediately after their installation. 

The general components of green walls are:

• Vegetation
• Growing substrate

Vegetation for Green Walls

The performance of a green wall system is highly dependent on the type of vegetation employed for the green wall system. The shading and temperature regulation benefits of a green wall system are dependent on the thickness of the vegetation and its transpiration processes. 

The plants are selected based on their orientation and the climatic conditions, along with the local weather.

The factors of vegetation that influence the cooling benefits are:

•  Evergreen and native plants are used for both cooling and less maintenance.
• The height of vegetation, leaf reflectivity, and leave emissivity

Compared to green facades, leaving walls offers a wide selection of growing methods and plants. Green facades are mostly limited to climbing plants. In terms of life cycle performance, a living wall is mostly preferred.

Growing Substrate for Green Walls

The substrates for growing vegetation for green walls are really important for their long-term performance. Popular substrates that are used for green walls are rock wool, coir, and potting soil. Hydroponic media with nutrients is also used. It is preferred to use a lightweight substrate to consider the weight of the growing vegetation.

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