Roof Garden | How To Build A Modern Rooftop Garden

Rooftop Garden
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Are you planning to have Small Roof Garden? And looking to enjoy a healthy environment and the precious occasion on your rooftop with your friends and family. Designing a roof as a natural garden is one of the best options to beautify it. Nowadays, due to the shortage of outdoor gardens and parks, people are shifting their roofs to rooftop gardens.

So, in this article, you are going to discover the types of roof gardens and how you can build a modern rooftop garden.

What is Roof Garden All About?

Roof Gardens also have other names such as Garden Roof, Green Roof, or Rooftop Garden. It consists of specialized roofing arrangements to support vegetation growth. Usually, it behaves like an outdoor chillax room consisting of different-sized planters full of a wide range of evergreens, shrubs, beautiful flowers, and grasses. Besides, it also has provisions to support occupancy for inhabitants to have pleasure sitting facilities.

Rooftop Garden Design

There are many factors that contribute to designing a roof garden. Now, you might be thinking of having one and planning to enjoy it. There would be various questions popping up in your mind. But the question is “Am I able to install it?” Yes! The basic factor that gives you the opportunity to install a modern roofing system is the load-bearing capacity of your roof. Is your roof able to sustain the constitutes of a roof garden as an additional weight?

To check the criteria, you need to take help from the Engineer specifically the Structural Engineer. He will calculate the factors and provide you with the complete design details. This calculation will give you an idea of whether you can construct a roof garden or up to what extent you can cover the area for it. So, why is this exercise necessary? To discover more, you should know about the constituents of roof gardens. So, what are they?

What are the Constitutes of Roof Garden?

Usually, Roof Gardens install in two ways, i.e., Conventionally and Protective-membrane roofing systems. This roofing system is mostly installed after thermal insulation and waterproofing of the deck. The following are the typical components of Roof Garden along with their functions:

Roof Garden Structure

Roof Resistant Layer

Roof Root Barrier Membrane or Roof Resistant Layer is the layer of PVC, polyester or polythene. This layer protects your primary waterproofing layer and structure from roots when installing a green roof.

Drainage Layer

The drainage layer is provided to remove excess water from the growing medium or soil. Gravel, specialized polymer foam panels or highly porous polymeric mats are used as drainage layers.

Filter Layer

Basically, this layer is made up of geotextile material and placed to prevent fine particles in soil from clogging the drainage layer.

Growing Medium

To reduce weight on the roof, the artificial growing medium is used to support vegetation in lieu of regular soil. Its composition and depth depend on the type of vegetation and plants.

Plants or Vegetation

The final stage is the placement of plants and vegetation. The selection of Plants or Vegetation is depending on the local climate conditions. However, the restriction of climate conditions can reduce the selection options.

What are the Classifications of Roof Garden?

Before installing the Roof Garden, it is important to know the classification of Roof Gardens. They are classified as Extensive and Intensive.

Extension Roof Garden

The Typical weight of the roofing system is less than 300 Kg/m2  and the typical depth for growing medium is less than 200 mm. It provides ecological beneficial settings and low maintenance with no irrigation system is needed when plants have been established. you can view it from surrounding buildings.

As they are shallow and have lightweight growing mediums, they can only support small plants such as herbs, grasses, and wildflowers. Because of the low structural loading demands, these can built-in existing buildings.

Intensive Roof Garden

The Typical weight of the intensive roofing system is greater than 300 Kg/m2  and the typical depth for a growing medium is greater than 200 mm. It provides complete park or garden-like features. It involves high maintenance with an irrigation system needed along with regular gardening maintenance required.

These can support small trees and shrubs. Because of the high structural loading involved, these only can be incorporated into the original building design.

How to start with the Roof Garden?

Modern Roof Garden Design

As stated earlier, the Structural Engineer determines the existing or required load capacity of your roof. So, start with the consultation with designers and consultants to check out how much your roof can carry additional weight.

Once the capacity is determined, the design process started. Depending on the capacity and the desired finished product, the Roof Garden is designed as an Extensive Roofing System or Intensive Roofing System. The lightweight components for preparing it should use because the rooftop garden weight plays a vital role in your design.

After confirmation that what you need to install,  treat your concrete roof deck or screed with a waterproofing layer. Do not forget to get services from the waterproofing experts as they can provide reliable products and services.

Once a primary waterproofing layer is applied to the concrete roof deck or screed, you can roll out the root barrier membrane across the length of the roof. Cut the barrier membrane to size. It is possible to overlap and tape the barrier. You can now install the drainage membrane layer on top.

It is beneficial to select a drainage layer integrated with geotextile fabric. This geotextile layer also filters out fines and other particles to ensure your green roof can thrive. This bonded geotextile filter layer also saves time on installation compared with when you have to lay a separate loose geotextile layer.

After completion of drainage layer installation, now it is time to place the growing medium according to the design requirements. The growing medium should place properly and the dept should be set as per requirement. Finally, the vegetation comes depending on your choice of moss, grass, plants, sedum, and flowers.


As the emerging trend of the rooftop garden, the concrete deck design should have the provision of roof landscaping and its other related features. Roof Garden can fulfill your needs for the gardening hobby. Moreover, it can optimize the environment for human residents to meet the needs of people to approach nature. While designing a roof garden, the favorite factors, such as wide field of vision, good illumination, large temperature difference, little pollution, small people flow as well as adverse factors concerning the field, bearing capacity, soil, and wind power keep in calculations.

Finally, don’t forget to share your views about the roof garden that you already have, and how you spend your time while hanging in it. If you are planning to construct it, your queries are open to coming in the comment section below.

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Muhammad Ali Raza is the Founder of Constructsmarlty and a professional Civil Engineer. He started his career in the construction industry in 2012 and has been trying to pursue modern methods and innovations in the construction sector. He spends his spare time catching up with new trends and technology. His passion is to help people in the home and building construction process.
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Very nice, your ideas are amazing, keep it up 🙂

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