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Everything You Need To Know About Green Roofs

Updated Oct 28, 2022

Updated Oct 28, 2022

Home > Roofing > Everything You Need To Know About Green Roofs

Green roofs are growing in popularity throughout North America but have been used throughout Europe for some time. Green roof systems are additions to a home’s roof that provide space for growing vegetation and flora. Depending on the types of plants, a green roof may even have drainage layers or be modular.

This article sheds light on everything you need to know about green roofs, including the different types of green roofs, environmental benefits, and much more.

What Is a Green Roof?

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Green roofs, otherwise known as vegetative or eco-roofs, are roofs with a layer of vegetation planted on top of a waterproofing system. The waterproofing system is installed over a slightly sloped or flat roof.

There are three primary types of green roofs:

  • Extensive green roof: An extensive green roof is often not accessible and features a modest roof load, minimal watering and gardening requirements, and limited plant diversity. Extensive green roofs typically have shallow growing mediums less than 6 inches deep.
  • Intensive green roof: An intensive green roof has much more soil and a deeper growing medium of several feet. Due to the deeper growing medium, an intensive green roof can support a larger diverse plant selection, even small trees. They will require frequent maintenance and are usually accessible.
  • Semi-intensive green roof: A semi-intensive green roof combines the extensive and intensive green roof types. The depth of the growing medium will range from 6 inches to a couple of feet.

Benefits of Green Roofs

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Public Benefits

Green roofs provide many benefits for the environment and urban areas, promoting biodiversity, and improving sustainability.

  • Moderates the Urban Heat Island Effect: Plants on horizontal and vertical surfaces cool cities during hot temperatures, reducing the Urban Heat Island Effect that increases a city’s temperature. Green roofs cover the black roofing materials exposed on conventional roofs as well, moderating hot temperatures.
  • Beautifying the area: Many urban environments don’t have a lot of green spaces. Adding a green roof can provide a splash of green and make the area more beautiful.
  • Improve air quality: The plants on a green roof can filter toxic gases and capture atmospheric deposition and airborne pollutants. Green roofs can also help to moderate the temperature, lowering demand on power plants and resulting in less carbon dioxide and pollutants being emitted into the air.
  • Waste diversion: Green roofs can reduce waste sent to landfills by using recycling materials in the green roof design and increasing the life of waterproofing membranes on a roof. It can improve the life span of ventilation, heating, and air conditioning systems by reducing their usage and improving energy efficiency.
  • Building community spaces: Green roofs can be used for many community functions, including a community garden, restaurant terrace, or recreational spaces, such as a children’s playground or lawn bowling. All of these promote community endeavors, bringing people together.
  • Stormwater management: Green roofs retain precipitation as it falls. During summer, this can be close to 90% of the rain that falls. In contrast, green roofs will absorb anywhere from a quarter to half of the precipitation that falls in winter. Not only do green roofs absorb rainwater, but they improve the temperature of the water and filter the water, improving water quality as it runs off the roof. The stormwater runoff retention and delay in stormwater falling off a roof surface also reduces the stress on sewer systems during heavy rainfall.
  • Increases job opportunities: Green roofs are a lot of work to create and install. As a result, increasing the number of green roofs often leads to more jobs and revenue in a community as people have vegetated roofs installed and maintained.

Personal Benefits

In addition to the fantastic environmental benefits green roofs offer, they have a host of personal benefits for a homeowner:

  • Improved roofing membrane durability: A green roof can reduce a waterproofing membrane’s exposure to substantial temperature fluctuations, which can cause ultraviolet radiation and micro-tearing, decreasing a roof’s expected life span.
  • Reduce noise: Green roofs absorb noise, particularly low-frequency sounds, reducing noise pollution. Intensive roofs can decrease sound by 46 to 50 decibels, while extensive green roofs can reduce outdoor noise by 40 decibels.
  • Improved energy efficiency: Green roofs create greater insulation, lowering the amount of energy required to maintain a comfortable temperature within a home. This can improve a utility bill, especially during winter and summer when homes are most susceptible to energy loss.
  • Increases fire retardation: Green roofs boast a lower burning heat load when compared to conventional roofs. The burning heat load of a home is how much heat a home would generate as different substances burn. As a result of the lower burning heat load, a green roof can improve fire safety for the residents and neighboring homes.
  • Improves marketability: Homes with green roofs are attractive and an eye-catching symbol of the green building movement. If you have a green roof, this may be an added incentive for buyers to pick your home. Corporate buildings with green roofs are even said to have lower employee and tenant turnover and increased property value.

Design Benefits

Design benefits include various benefits to the environment and humanity. Here are just a few of the design benefits green roofs offer:

  • Improved health: Green roofs improve the water quality of stormwater and reduce pollution. Both of these factors can improve the community’s overall health, decreasing the need for healthcare.
  • Greater biodiversity: Green roofs create a habitat for bird species, especially migrating birds. They can support a variety of plants and invertebrates, improving biodiversity, especially in urban areas with few plants.
  • Educational opportunities: A community green roof is a beautiful way to promote hands-on teaching and learning with students or people interested in biology and green roof technology.

Final Thoughts

Green roofs and roof gardens provide a huge number of opportunities to improve general health, grow a tight-knit community, and improve a home’s value, energy savings, and noise levels. We hope our piece on everything you need to know about green roofs helps you decide if a living roof is right for you and your goals.

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