Green roof systems- Are they exist?

Green roof systems are modern roofing technology which can solve many urban constraints that are quite problematic in many countries.

So, What are green roof systems? A green roof system is an extra layer provided on the existing roof for growing plant media and depending on the types of green roofs the plants may be modular or have drainage layers. These green roof systems are water-resistant and root repellent, so that the structure is safe and protected from damages.

Green roof technology has been implemented in many countries on large scale and from them we are getting good amount of results.

But in India, the green roof systems are quite less and require proper education on the benefits and advantages of green roofs.

Before installing a green roof make sure you consult a structural engineer or Architect specialized in green roof systems and then based on his/her suggestions you can start constructing your dream house.

So, In this article, we try to cover more information about Types of green roof systems, layers of green roofs, Advantages, and Disadvantages of green roof technology.

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Types of green roof systems

The green roof systems are divided into three main types namely, intensive, extensive, and semi-intensive green roofs.

Extensive roofs are lightweight green roof systems that have thinner growing media ranges from 6 to 20 cm depth. Intensive green roofs are thicker and the growing media ranges in thickness from 20 to 100 cm. semi-Intensive green roof media will have both intensive and extensive growing media ranges from 12 to 25 cm.

So, the intensive roof system is costlier than other types of green roof technology also the extensive roofs have a lower cost.

Due to thicker plant media and heavy soil mass, Intensive green roof weight ranges from 180 to 500 kg/m² whereas extensive green roof weighs about 60 to 150 kg/m² and semi-intensive weights between 120 to 200 kg/m².

An intensive green roof requires high maintenance and irrigation whereas extensive requires less maintenance.

Layers of green roof

• Plants or vegetation: This media layer gives extra oxygen and also takes all the heat that is coming from the sun and helps to maintain roof cooler.
• Growing Medium: It will facilitate the growth of plant media.
• Filter fabric: It will remove the excessive organic matter that comes with the drain water from the top and helps in protecting further layers.
• Drainage Layer: This layer provides a way to escape excess water from the rooftop to remove unnecessary weight.
• Root Barrier: This layer ensures that the roots cannot penetrate through and helps in the proper management of green roofs.
• Insulation layer: It is an extra protection layer from all thermal and physical damages on the roof.
• Waterproofing Membrane: It helps the deck of the slab to keep dry and also ensures that no water is penetrated during heavy rains.

Advantages

• Improves the drainage system during heavy rains.
• Due to many layers on the top, the life expectancy of the actual roof increases.
• Green roof systems will improve the thermal performance and helps in the energy efficiency of buildings.
• It is helping the environment by observing the excess carbon dioxide emissions from the building.
• This roofing technology will support the growth of wildlife sanctuary in cities.
• A green roof will definitely improve the air quality to some extent and according to a recent study, it will help the environment to reduce 37% of sulfur dioxide, 21% of nitrous acid, and o.2kg of dust particles/m² each year.

Disadvantages

• The cost of green roof technology is more than traditional roofing systems.
• The green roofs are heavier and also we discussed the weight will be in the range between 60-500 kg/m², so the weight of green roofs is to be necessarily considered while designing a structure.
• The roofs require extra maintenance for longer life.

Case studies

1. Extensive, Center Parcs, Woburn, UK – Read Full article
2. Leeds Skelton Lake Services, UK – Read full article