Rooftops that have gone unnoticed in cities all over the world can have a significant impact on how we conserve energy. These vast and underutilized spaces have the potential to reduce energy consumption while simultaneously producing food. They also have the ability to provide safe havens for animals in need of protection.
All that is needed is a simple rooftop garden to complete the look. We can transform our cities into more environmentally friendly environments by increasing the number of green spaces in the sky. Everyone will benefit from this.
- What are Rooftop Gardens?
- How Rooftop Gardens Conserve Energy
- The History of Rooftop Gardens
- The Extra Benefits of Green Roofs
What are Rooftop Gardens?
The concrete behemoths that dominate a city’s skyline tend to overlook the additional land space that is hidden from our view by surrounding buildings. Due to a reduction in the amount of available ground-level land in urban areas, it is now more important than ever to consider ways to expand upwards.
Rooftop gardens provide a solution to the urban crisis we are experiencing. They are a simple and cost-effective method of lowering a building’s energy consumption while also providing a variety of other benefits to occupants.
Types of Rooftop Gardens
Rooftop gardens can be divided into two categories: intensive and extensive gardens.
1. Intensive Green Roof
When applied to a flat roof, this system involves spreading a thick layer of soil across the surface of the roof, which is often several inches deep. It is possible to use a raised garden bed to cultivate a more diverse range of plants in certain situations. Vegetables can be included in this category. Because of the large amount of nutritious soil that is used there, it is possible for larger plants and trees to thrive.
Intensive green roofs are commonly found on commercial structures. The structure must be able to withstand the weight without breaking. They are frequently more labor-intensive to maintain than other types of rooftop gardens.
They do, however, have the added advantage of being able to produce food right in the heart of a city. The transformation of a bland and otherwise unusable space into a beautiful and relaxing space for residents and employees alike can be achieved if the work is done correctly.
2. Extensive Green Roof
When compared to the intensive green roof system, the extensive green roof system requires a smaller amount of growing medium. A thin layer of soil is spread across the roof and is home to a variety of hardy plant life. Succulents and grasses are examples of such plants.
Growing quickly and absorbing heat, these low-maintenance plants are a good choice. Meanwhile, they are cooling down the entire building.
They are only a couple of inches thick. This results in mini gardens that are suitable for a variety of different rooftops, including slanted suburban homes (and yes, even earthships) and other types of structures.
Aesthetically pleasing green roofs can be found on large buildings. They use unique vegetative designs to cover unsightly concrete surfaces.
Drought-resistant plants can withstand even the most severe weather conditions. They are an excellent choice for smaller residential buildings that want to reduce their energy consumption and save money.
How Rooftop Gardens Conserve Energy
Rooftop gardens make use of two of the most effective forms of insulation available: soil and vegetation. Plant life has always provided a natural refuge from the heat, whether it be in South America’s tropical jungles or Europe’s coniferous forests. The dense canopy of trees and dense underbrush provides protection from the hot sun, allowing the ground beneath to remain cool and breezy.
On hot, sunny days, the temperatures at the tops of buildings can soar to mind-boggling heights, reaching as high as 150 degrees F. This heat will naturally pass through the building if it does not have an insulating layer applied to it because the concrete exterior acts as a conductor.
In order to regulate the temperature, air conditioning systems must be used, resulting in an unnecessary expenditure of money, energy, and other resources. Cooling costs can account for up to 70% of the total electricity bill in hot climates, according to the International Energy Agency.
Atmospheric gardens on roofs are extremely effective insulation systems that can lower the cost of cooling a building significantly. In addition to the soil’s natural ability to act as an insulator, the plants growing on top of it can lower the temperature by producing photosynthesis and transpiration.
In hot weather, the shade provided by a tree can feel 2–9 degrees Fahrenheit cooler than the shade provided by a roof or other structure due to these natural processes.
With the addition of water to the equation, the cooling effect is multiplied by two. Moisture-laden soil naturally cools as water evaporates from it, causing the soil surface below to become cold.
While this process is particularly beneficial in the summer, rooftop gardens can also help to keep the building’s heat in during the winter by preventing heat loss. Adding a layer of insulation to a roof is beneficial in most weather conditions, as it helps to maintain stable temperatures in buildings while also protecting them from extreme and harsh weather conditions.
The Heat Island Effect
Traditional roofs are made of materials that absorb large amounts of heat emitted by the sun during the day. In urban areas, the dense concentration of buildings creates pockets of warmth known as “heat islands,” which can cause the temperature of the surrounding air to rise.
City dwellers experience higher temperatures on average than those who live in open countryside. The difference in temperature during the day and evening can be as much as 1.8–5.4°F due to large cement structures absorbing heat and interfering with the natural cooling process. The difference can be as much as 22°F in the evening.
In order to keep their homes cool, city dwellers must consume a significant amount of energy, resulting in higher greenhouse gas emissions than their rural counterparts.
In order to combat the heat island effect, covering urban rooftops with greenspaces would be a fantastic solution. Not only would these rooftop gardens help to lower the temperature of the surrounding area, but they would also help to remove harmful pollutants from the air through the use of naturally occurring filtration systems. Urban jungles have the potential to make our work and living environments more healthy for both our bodies and the environment.
Saving Money and Energy
Money saved is largely a result of environmental factors, including climate and, of course, electricity consumption. Because heaters and air conditioners are rarely used in temperate climates, the savings will not be as significant as they will be for those who live in more extreme temperatures. The fact is that, regardless of the weather, rooftop gardens can assist in lowering overall energy consumption costs.
When it comes to rooftop gardens, one study found that buildings in Canada with rooftop gardens save 20% more energy in the summer than buildings without rooftop gardens on the upper floors. This translates into a 6 percent reduction in energy consumption for the entire building if it has five or more floors, and a 10 – 12 percent reduction in energy consumption if the building has only two or three floors.
In fact, the city of Toronto has estimated that it could save approximately $22 million if it were to implement a comprehensive city-wide initiative on a large scale.
The savings that buildings can generate in more extreme weather conditions can be significantly greater. Another study found that green-roofed homes in the Middle East had lower energy consumption on average, by 24 percent to 35 percent, compared to conventional homes.
In climates with extremely high temperatures, air conditioning systems consume up to 70% of the energy available to them. The installation of a simple rooftop garden could result in a reduction of up to 50% in the average electricity consumption of buildings.
The History of Rooftop Gardens
Green roofs have traditionally been the norm in many Scandinavian cultures, particularly in the countryside. In the past, turf was used to cover the roofs of homes, churches, and other small buildings to keep the elements out. These roofing systems, which are commonly referred to as “sod roofs,” were widely used up until the 18th century.
Those who lived in northern countries during this time period recognized the advantages of covering their roofs with natural materials. The layer of soil and vegetation on top of their homes served as an effective insulation, keeping them safe from the harsh snow of winter and the scorching heat of summer days.
When you consider how labor-intensive it was to construct a sod roof without the use of modern-day tools, the system must have been quite effective.
The Extra Benefits of Green Roofs
The use of concrete slabs to create green spaces has a number of advantages in addition to the insulation properties they provide. The gradual encroachment of urbanization on natural habitats and landscapes has resulted in vast tracts of land being stripped of their natural ecosystems.
This has had a devastating impact on pollution, wildlife populations, and the general well-being of the human population. We can help to reverse some of the more detrimental effects of urban sprawl by reintroducing nature into our lives.
1. Reduces CO2 Emissions
With a city full of green roofs, it would be possible to significantly reduce the amount of CO2 emitted from these areas as well. Rooftop gardens have the ability to absorb CO2 from the air and release oxygen in its place, resulting in a healthier urban environment overall.
At the moment, CO2 emissions are the most significant source of greenhouse gas emissions caused by humans. The use of environmentally friendly roofing materials could help us reduce this percentage while still conserving energy.
According to a study conducted in Michigan, if every rooftop in Detroit was covered with greenery, these roofs would be able to absorb the equivalent amount of CO2 produced by 10,000 trucks over the course of two years.
As a bonus, this carbon is being absorbed in areas that are in desperate need of it, as cities have significantly less vegetation and produce significantly more CO2 on average than their surrounding regions.
2. Provides a Habitat for Wildlife
Many animals have been displaced as a result of the destruction and clearing of large swaths of natural habitats for urban development. Rooftop gardens provide nesting areas and insect homes, attracting a variety of birds to their territory. Flowering plants on roofs provide very important food and habitat for bees, which have been in desperate need of assistance in recent years, and they should be encouraged to do so.
In fact, a report found that 37 species of birds were found on just ten rooftop gardens in New York, indicating that we shouldn’t underestimate the ecological value of these rooftops. Woodcocks, magnolia warblers, flycatchers, falcons, and hummingbirds were among the species found in this flock of birds, which included some rare and endangered species. These birds do not normally reside in urban areas, despite the fact that they are an important component of the ecosystem.
3. Allows for Better Storm Water Management
Rooftop gardens capture rainwater and slow its flow down to road-level surfaces, allowing cities to better manage the massive amounts of water that pass over them during severe storms and flooding. In studies, it has been discovered that green roofs can reduce water run-off by an average of 50%, allowing cities to retain healthy amounts of water that can help them stay cool when the sun returns.
When a large number of major city buildings install green roofs, it relieves a significant amount of pressure from storm water drainage systems that are already dealing with the effects of climate change and the resulting super storms and flooding.
4. Can Produce Food
When it comes to producing food, rooftop gardens have the ability to do so in areas where there is a high demand for it: densely populated cities. A city’s transportation costs are reduced when food is grown in the heart of the city. This is due to the fact that customers are located in close proximity to the farm.
It also has the additional benefit of reducing carbon footprint. People will no longer require trucks to transport food from remote locations.
The food grown on these rooftops is often more nutritious than the food served on a plate at a restaurant. This is due to the fact that it is still fresh and does not require any processing to be done in order to preserve it.
Vegetables lose their nutritional value relatively quickly after they have been harvested by humans, according to research. This figure is significantly higher than most people would anticipate. It is possible that spinach will have lost more than half of its vitamin C content by the time it reaches a person’s plate.
The practice of cultivating crops on rooftops also lessens the need to clear forest land to make way for new farmland, which has a significant impact on environmental degradation and global warming, respectively. The good news is that we, as humans, have a diverse range of edible species at our disposal, which we can grow on our rooftops in a variety of climates.
Those require only a minimal amount of maintenance. Not only does this type of rooftop food production have a lower carbon footprint than other forms of food production, but it can also be “carbon negative” in some cases because it reduces energy consumption.
5. Can Boost our Mood
Green spaces in urban areas have been shown to significantly reduce overall stress levels in a population. A hypothetical city with green roofs brimming with chirping birds, lush foliage, and nutritious food could accomplish this even more effectively.
A rooftop garden provides a welcome respite for employees and residents who live in cramped, industrial spaces with limited access to natural surroundings and fresh air.
It is impossible to overestimate the importance of these green spaces. Those who grew up in urban areas with few green spaces had a 55 percent higher risk of developing mental disorders such as anxiety, depression, and substance abuse than those who grew up in rural areas with plenty of green space. This was found in one study. As a result, fewer people are reliant on expensive pharmaceuticals or doctor visits, which reduces the burden on the healthcare system.
Rooftop gardens not only reduce stress and instances of mental strain, but they also have the added benefit of increasing productivity. It has been discovered that offices with a significant amount of greenery can increase employee productivity by up to 15 percent. For example, a city that is 15 percent more productive as a whole would reap significant economic and social benefits, resulting in a happier and healthier life for all residents.