rooftop garden

9 Reasons for a commercial rooftop garden

The Rooftop Garden is now a common site in modern commercial landscaping. This is not surprising as there are many great reasons for having one.

The Rooftop Garden

It is a type of garden which is built on the roofs of the buildings. It means that roofs are covered with plants such as trees, shrubs, bushes, and grass. We can also say that a rooftop garden is the environment or nature in the sky. The rooftop garden is an excellent technique to improve the urban areas of the building by using the landscape design, which can convert the outmoded site into a valuable space that delivers ecological and economic facilities. The possible solution to the urban crisis is a rooftop garden.

Types of Rooftop garden

There are three types of rooftop gardens:

  • Extensive Roof Garden

The extensive roof garden is suitable for those roofs that bear little capacity. The cost of an extensive roof garden is lower as compared to other types of rooftop garden. The plants used in this type of garden are not very deep, and their nutrients demand is low. This type of garden is familiar with residential homes.

Green Rooftop - Reds Landscaping & Design
Aerial view of rooftop garden in urban residential area.
  • Intensive Roof Garden

In this type of garden, all the ground garden things, such as bushes, lawns, perennials, and trees, can be planted. In this type of garden, there is no limitation on design and individuality except a few things that must be considered. The intensive roof garden is expensive as compared to the extensive roof garden. These types of gardens are mainly found in commercial buildings.

Skyscraper Rooftop Garden - Reds Landscaping & Design
Green corner with chairs and potted plants and trees on rooftop of skyscraper.
  • Semi-Intensive Roof Garden

This type of roof garden falls in between extensive and intensive roof gardens. The cost of this type of garden is higher than an extensive roof garden but lower than an intensive roof garden. Various grasses, herbaceous perennials, and shrubs can be planted in a semi-intensive rooftop garden, whereas bushes and trees are missing.


Roof garden with green plants and silver which balls and wooden terrace with rest chairs - Reds Landscaping & Design
Roof garden with green plants and silver which balls and wooden terrace with rest chairs.


9 Reasons to choose a commercial rooftop garden

A rooftop garden provides a smart and easy way to enjoy a good environment, stunning view, and satisfaction in the city's heart. Beyond the decorative benefits, several other significant and inspiring reasons force you to establish a rooftop garden on your building. Some of these reasons are given below.

  • Energy saving for cooling

"The urban heat island effect" is a phrase used to define what occurs to an urban building as it speedily absorbs heat from the sun. The rooftop garden significantly decreased the use of energy. Roofs of concrete and tarmac retain heat and increase the temperature by up to 10ºF than the surroundings, whereas green roofs decrease the heat gain by shading, transpiration, insulation, and thermal loss. Research showed that the green tops of Chicago’s buildings reduce the need for air conditioning by up to 10% (Liu and Baskaran, 2003). In another study, green roofs decreased solar heat gain by as much as 95% and reduced the cooling needs by 25 to 50% (MacKenna).

  •  Reduction of emission from power generation

The primary harmful emission from electric power generation includes carbon dioxide (CO2), methane (CH4), nitrous oxide (NO2), nitrogen dioxide (NO2), sulfur dioxide (SO2), small particulate matter and volatile organic matter. In these, some are greenhouse gases that contribute to global warming and climate change, while some contribute to the degradation of air quality. Studies showed that electricity's total carbon emission factor is 422 g/kWh, including 418 g/kWh for CO2, 0.006 g/Wh for CH4, and 0.014 g/kWh for NO2. Conserving energy due to green roofs reduces the emission of these harmful gases.

  • Storm Water Runoff Management by a Rooftop Garden Installation

Green roofs significantly decrease the runoff of the rainwater by retaining it, as a result, the risk of urban flooding is reduced. The retaining water capacity of the green roof depends on climatic conditions (i.e., frequency, volume, and intensity of rain) and the substrate of the garden (i.e., depth, drying rate, and saturation). Research showed that the rates of monthly water retention varied between 40% and 100% on two green roofs in the Neuse River watershed (Moran et al., 2003). In another report, Simmons et al. (2008) stated that among six different extensive green roofs vegetated 4 inches, the highest runoff between 88% and 44% for medium and large rain events.

  • Air Quality Improvement

Green roofs significantly improve the quality of air through adsorption. Nitrogen oxide, sulfur dioxide, carbon monoxide, airborne particulate, and ozone levels have been presumed to decrease due to the roof garden's presence. The result of a research study showed that approximately 109 hectares of roof gardens eliminate a total of 7.87 metric tons of air pollutants annually in Toronto, Canada (McPherson, 2008). In another study, Yang et al. (2008) determined pollution removal by the rooftop garden in Chicago. They reported that about 1675 kg of air pollutants were removed by 19.8-hectare roof gardens within one year, in which 52% of the total was O3, 27% NO2, 14% airborne particulate, and 7% SO2. They concluded that the maximum air pollution removal was recorded in May, whereas the minimum removal of pollutants was observed in February.

  • Extended the building life and reduce maintenance

Usually, the roofs of buildings are exposed to the sun, rainfall, snowfall, and numerous other components on a consistent basis. Due to these factors, the roofs of the buildings need maintenance and repair at intervals of a few years.

Generally, a rooftop garden protects the top of a building from these factors. The waterproofing material underneath a rooftop garden has protected the roof from light, temperature, fluctuation, and physical damage. That’s why roof gardens can increase the building's life and decrease maintenance. Studies show that roof gardens extend the life of the existing fabric by up to 20%.

  • Relaxation and Happiness

Due to rooftop gardens, a person has direct contact with nature in extensive crowded areas. After a hard-working day, spending some time in nature relaxes a person and enhances their mental health. Studies show that having regular contact with green spaces and wildlife in urban areas directly impacts mental health and happiness. Additionally, we mentioned earlier that rooftop gardens improve the air quality and water, which reduces the individual's stress.

Rooftop Garden - Reds Landscaping & Design
A well-designed roof top garden can add enormously to the enjoyment of life of the users. Group of gardeners tending to crops.

The results of the research study showed that the rooftop garden on the commercial building enhances the satisfaction of the occupants and increases their creativity, productivity, and physiological well-being. Those with fewer stress levels also mean happier and more productive employees and easier employee recruitment for companies.


Rooftop Vegetable Garden - Reds Landscaping & Design
Rooftop garden, Rooftop vegetable garden, Growing vegetables on the rooftop of the building, Agriculture in urban on the rooftop of the building.
  • Increase the value of the property with a Rooftop Garden

The rooftop garden increases the sale and rental price of a building. The most noticeable benefit of a rooftop garden is its valuable pleasantness, which improves the real estate value of the structure it occupies for a relatively modest expenditure. Researchers reported that a roof garden typically adds 15–25% more value to the property in the high-end neighborhood.

Colourful Cityscape Rooftop Garden - Reds Landscaping & Design
A colourful city rooftop garden.
  • Provide diverse habitat

When planted with indigenous vegetation, rooftop gardens can provide a significant environment for intrinsic bird and insect populations. Green roofs create a flourishing eco-friendly habitat. Each green roof supports varying habitats, dependant mainly on the type of vegetation included. Migratory birds might also be attracted to green rooftops. A research study showed 172 different species of birds and other wildlife on eleven different green rooftops.

Wooden Pergola - Reds Landscaping & Design
Rooftop garden in urban setting.
  1. Sound Insulation with a Rooftop Garden

Sound is a vast destructive force, especially in commercial building areas. Workers in a commercial building do not want to listen to the rumble of heavy traffic outside their office. Similarly, if you are in your home, you would undoubtedly not appreciate the roar of jets or the noise of heavy traffic late at night. A green roof provides an extra layer of insulation. According to research, it will absorb up to 30% of environmental noise pollution. You can get on with work free from destruction or sleep more soundly in your bed at night.


Rooftop garden - Frequently Asks Questions

How do you build a rooftop garden?

The rooftop garden is an ideal way for urban gardeners to expand their space. It makes good use of frequently unused and wasted space. There are a few things to keep in mind when creating a rooftop garden.

Start with a plan: Before you head to a nursery, consider whether you wish to install raised beds or would rather garden in containers and approximately how many of each you would like to have.

Consult with a building engineer: It is a good idea to consult with an engineer to ensure that the roof can support the weight of your garden and that it is well waterproofed.

Lightweight materials: If the building can take the extra weight of a rooftop garden, it would be best if you tried to use as little weight as possible. Use plastic, fiber glass, and foam planting containers. Use lightweight potting soil rather than garden dirt.

Check your access: You will need easy access to the roof to transport materials, tools, soil, and plants up and down. A narrow, rickety staircase may be a challenge.

Use solid and long-lasting materials: Opt for larger pots, such as drums or recycled paint buckets, for containers. If installing raised beds, aim to make the beds at least 10 inches deep to ensure adequate soil for root growth.

Find a water source: Rooftop beds and containers will dry out quickly and must be watered daily during the hottest parts of summer. If desired, an automatic watering system can be set up to reduce the time spent watering.

Incorporate Windbreaks: Keep in mind that a rooftop garden will be considerably windier than a typical garden. So you will need to incorporate windbreaks into your rooftop garden design. Try using trellises or some other latticed windbreak for your rooftop garden.

Pick the suitable planting medium: In rooftop containers and raised beds, soil mixed with a bit of cocopeat is your best friend. Not only does it hold water, but it is also lightweight and would not compact over time.

If you keep these things in mind, you will find that your rooftop garden can provide a lovely and great place for you.

Construction of a Commercial Rooftop Garden at Habitus Apartments South Melbourne


What are the benefits of a rooftop garden?

There are various environmental, commercial, and physiological benefits of rooftop gardens, which include:

  • Increase access to safe outdoor green space.
  • A venue for urban food production.
  • Promotion of individual, community, and cultural diversity.
  • Area for study and horticultural therapy.
  • Improve the quality of air and absorption of carbon dioxide.
  • There is usually good sun exposure.
  • Support for a rainwater collection system and reduce the run-off of stormwater.
  • They make use of unused or underused space.
  • A rooftop garden helps to decorate your rooftop, which will be a relaxing gateway.
  • The rooftop provides fresh, organic, and healthy fruit and vegetables, a real gift in urban areas.

Are rooftop gardens expensive?

In my opinion, it may be and maybe not. It depends on you whether you want to build an extensive rooftop garden or an intensive one. The cost of the expansive roof garden is less as compared to the intensive rooftop garden. The intensive roof garden's cost depends on size, use of construction materials, and garden design. Although the initial cost of installing an intensive roof garden is high, it pays for itself. Whether you are installing a rooftop garden for pleasure or practical purposes, you will be rewarded with a marked reduction in energy consumption and power bills, as well as an overall increase in quality of life.

Do green roofs need drainage?

It has been reported that the soil in the rooftop garden can retain 15-20% of the rainfall for a two to three-month period. Due to these conditions, it is often misconceived that roof drainage is not required on rooftop garden systems. This theory is not only incorrect but also dangerous. The water needs to be removed from the system to observe the structural limitations of the building. The rooftop garden plays a vital role in slowing down water runoff from the roof to the city’s storm sewer system but does not absorb or consume the whole water. That’s why drainage is essential on green roofs.

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MacKenna, E., Green Roofs: Energy Saving and Much More,

Liu, K. & Baskaran, B., Thermal performance of green roofs through field evaluation,
Proceedings for the First North American Green Roof Infrastructure Conference, Awards and Trade Show, May 29–30, 2003 in Chicago, IL, pp. 1–10.

Liu, K.K.Y., Energy efficiency and environmental benefits of rooftop gardens. Construction
Canada, 44(2), pp. 17, 20–23, 2002.

Moran, A., et al., A North Carolina field study to evaluate greenroof runoff quantity, runoff
quality, and plant growth. World Water and Environmental Resources Congress and Related
Symposia Proceedings of World Water and Environmental Resources Congress 2003

Simmons, M.T., Gardiner, B., Windhager, S. & Tinsley, J., Green roofs are not created
equal: the hydrologic and thermal performance of six different extensive green roofs
and reflective and non-reflective roofs in a sub-tropical climate. Urban Ecosystems, 11, pp. 339–348, 2008. resources/10 key benefits of roof gardens