What is Green Roof Construction?

Green roof construction is defined as a vegetative layer grown on the rooftop of the building. It is also called as roof gardens. Green roof construction serves the objective of green building construction. It helps to emerge energy efficient buildings.

The green roof reduce the temperature of the building and the surrounding air in multiple ways through shading and evapotranspiration. Evapotranspiration is the process by which plants absorb water through the roots and then take the surrounding heat from the air to evaporate the water.

Generally the roof temperature may increase up to 90 degrees which can be put down by green roof system. This also help to mitigate the urban heat island effect.

Components of Green Roof System

Components of Green Building; Image Courtesy: Green Building Alliance

The main components of green roof system are:

1. Vegetation
2. Growing Medium
3. Root Barrier
4. Drainage
5. Insulation
6. Membrane Protection
7. Membrane

1. Vegetation

• This is the top layer of the green roof.
• The plants selected for this purpose is dependent on the type of roof, climate, condition of the building. Tall and heavy vegetation can be used for flatter roofs and stronger buildings.  For slanted roofs lighter and shorter vegetation can be used.

2. Growing Medium

• It is the foundation for all the vegetation on the top layer.
• The type of medium, the mixture and depth depends on the plants selected for green roof.
• A win erosion layer can be constructed to prevent wind from blowing away the top soil.

3. Root Barrier

• This is provided for deep rooted plants like trees and shrubs.
• This barrier prevents roots from reaching the membrane on the bottom layer.

4. Drainage

• This is installed to remove excess water from the green roof.
• This make sure that the water is available for the plants consistently without over saturation.

5. Insulation

• It protects the membrane layer below.
• It prevents the weight of the green roof from crushing the insulation and impairing the membrane.

6. Membrane Protection

• The protects the membrane from deterioration. 
• It can be a layer of lightweight concrete, thick plastic or copper foil or any of the combination.

7. Membrane

• This is the bottom layer of the green roof.
• Separation between the green roof above and the structural supports below.
• The membrane must be strong enough to support the water weight and prevent seepage.

Also Read: Breeze Bricks - Why do You Need It?