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 build on the roofs of the buildings. It means that roofs cover with plants such as trees, shrubs, bushes, and grass. We can also say that a roofs 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 valued 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 the roof 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.
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 of 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.
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 roof garden whereas, bushes and trees are missing.
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 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 conditions 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 from 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 improved 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) determine pollution removal by the roof 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, roofs of the building are uncovered to the sunshine, rainfall, snowfall, and numerous other components on a consistent basis. Due to these factors, the roofs of the buildings need maintenance and repair after intervals of few years.
Generally, a roof 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 life and decrease maintenance. Studies showed that roof gardens extend the life of the existing fabric up to 20%.
Relaxation and Happiness
Due to roof 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 his mental health. Studies showed that having regular contact with green spaces and wildlife in urban areas directly impacts mental health and happiness. Additionally, we mentioned early that rooftop gardens improve the air quality and water, which reduces the individual’s stress.
The results of the research study showed that the rooftop garden on the commercial building enhances the satisfaction of the occupant and increases their creativity, productivity, and physiological well-being. Fewer stress levels also mean happier and more productive employees and easier employee recruitment for companies.
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 roof garden is its valuable pleasantness that improves the cost of the structure it occupies for a relatively modest expenditure. Researchers reported that a roof garden typically ads15-25% more value to the property in the high-end neighborhood.
Provide diverse habitat
When planted indigenous vegetation, Roof 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. Green rooftops might also be the stop of migrating birds. A research study showed 172 different species of birds and other wildlife in eleven various green rooftops.
Sound Insulation with a Rooftop Garden
Sound is vast destruction, especially in a commercial building. 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 the 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 rooftop garden. So it would be best if you tried to use as little weight as possible. Use plastic, fiber glasses, 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 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 benefit of a rooftop garden?
There are various environmental, commercial, and physiological benefits of rooftop gardens which includes
- 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 intensive. The cost of the expansive roof garden is less as compared to an intensive rooftop garden. The intensive roof garden 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 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 in green roofs.
Related Landscaping Ideas from Red’s Landscaping and Civil Pty Ltd
MacKenna, E., Green Roofs: Energy Saving and Much More, http://hubpages.com/hub/Green_Roofs_Energy_Savings.
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.
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