Benefits of Green Roofs

Planting green roofs has numerous advantages. It promotes sustainable development and also protects both biodiversity and the environment in towns and cities. 

Cost Savings for the Owner

Rainwater Management

As cities expand so do hard surfaces such as roads, rooftops and parking lots. These surfaces create artificially high rate of water runoff, which is extremely difficult for wastewater utilities to manage and results in untreated sewer overflows and rainwater runoff that pollutes local watersheds during heavy rainfall. Expanding traditional grey infrastructure capacity can be extremely expensive and often does not solve the problem.

This is why cities are turning to green infrastructure systems such as green roofs to deal with rainwater at the source, and minimize sewer overflow risk and protect water quality. Green roofs area a part of this solution.

Green roofs and other vegetated systems are able to reduce and regulate the quantity of rainwater reaching a building then drained off into the mains drainage system. Some of the rainwater is absorbed by the vegetated system (growing medium and plants) until it is saturated. The water retained in the soil is used by the plants in a process called evapotranspiration. Once the soil medium is saturated, the plant system is able to slow down the drainage of water into the rainwater drains. Green roofs absorb peak precipitation and delay runoff ("delayed effect") this cuts down on flooded drains during violent storms, and protects the watersheds that surround cities and municipalities. 

Hydroactive Smart Roof is a revolution in stormwater management with living infrastructure. Combined with Hydropack it adds up to an additional 2.3" of water retention. Not only Hydroactive Smart Roof is the only system to control the release of stormwater to meet specific stormwater management needs, it also passively irrigates the green roof to create an even more resilient system.

Thermal Comfort

The various layers of the vegetated system (drainage, filter, growing medium and vegetation) provide an extra layer of thermal insulation on the roof thus protecting the building from cold in the winter and combating the urban heat island effect in summer. The urban heat island is the concept that the hard dense material that makes up cities absorbs vast amounts of sunlight and can cause a city to be much hotter than the surrounding area. In this way the mechanisms of evapotranspiration, shade and reflection by the plants comprising the green roof can reduce the temperature of a building during hot summers.

When many buildings adopt green roof practices, the city can reduce its overall temperature in the summer. In short, green roofs can reduce utility costs for the building owner, and make a more comfortable city for everyone who lives in it. The Canadian Ministry of the Environment conducted a study in 2004 in the city of Toronto revealed that installing 6.5 km2 of green roofs in the city would be able to:

  • Lower the surrounding temperature by 1 to 2°C during the hottest periods
  • Eliminate 2.18 tons of greenhouse gases (carbon) and thirty tons of pollutants every year.

Extends the Life of Roofs

By protecting the waterproof membrane against thermal impact and stress (UV, indentation), green roofs help to prolong the life of roofs by as much as three times their normal useful life.

Property Value & Aesthetics

Green roofs provide aesthetic appeal, increasing the value of the property and the marketability of the building as a whole, particularly for accessible or highly visible green roofs. For example, American and British studies show that "good tree cover" adds between 6 to 15% to the value of a home. Green roofs transform rooftop eyesores into assets. The sound deadening capacity of green roofs can can raise the value of a home or commercial property even more around highways and airports.

Acoustic Comfort

The growing medium layers and the vegetation of the plant system absorb the noise from impact (rain, hail, etc.) and reduce the volume from aerial noise, making for a much more comfortable and quite building to live and work in.

Marketing Opportunities

Potential for local, regional, and national market exposure, depending on the uniqueness of the project. Our pitched roof installations, can maximize visibility and exposure of potential customers to your business.

Cost Reduction for Site Development

Potential to: reduce the size of HVAC equipment; reduce the amount of insulation used; reduce community resistance to new developments; faster approval process for new projects; reduced stormwater/wastewater charges from your municipality or utility; meet regulatory requirements for stormwater management for a minimal cost, reduces the size of stormwater management practices on the ground to maximize the development space of a property; satisfying minimum parkland / green space set aside, requirements.

LEED Credits and Energy Efficiency Incentives

Potential for grants related to energy efficiency and/or green roofs. Our green roof system can score more than 40 credits under the US and Canadian Green Building Council LEED certification system.

Low Maintenance

Extensive Green Roofs are very low maintenance systems that require minimum care and often require no permanent irrigation. Maintenance is limited but still very important. We recommend a minimum of 2-4 visits per year.

Solar Panel Productivity

By reducing surface temperature, green roofs dramatically increase Solar Panels efficiency

 

An extensive green roof instead of a roof garden
Unlike roof gardens, which present numerous restrictions to the architect (significant weight, depth of growing medium, limited area of use, etc.) and high costs for the end customer (installation and maintenance), extensive (or semi-intensive) green roofs are much simpler and less expensive to implement.  In fact, extensive green roofs can be easily established on all load-bearing components (especially wooden load-bearing components) as the load on the roof is minimized (the vegetated system generally weighs between 50 and 150 kg/m²) and the system is not very thick (under 15 cm deep) Maintenance costs are also minimized: the plants selected for the plant cover require neither mowing or watering (except for pitched roofs, very arid areas, and during periods of drought).

 

Environmental Savings

Rainwater Management

Green Roofs absorb anywhere from 20 to 100% of the precipitation that falls on the roof, depending on the season, previous rainfall, etc... In general, in the summer green roofs retain between 70% and 100% of rainfall events and in the winter less than 30%. Green roofs help reduce the volume of storm water flowing into streams and drainage systems. The Green Roof plants and growing media system filter pollutants and heavy metals from runoff water. In addition, runoff is delayed and the flow-rate is reduced. It is inexact to use runoff coefficient for green roofs as this coefficient varies all the time (depending on the saturation of the system).

Urban Heat Island Reduction

Through the daily dew and evaporation cycle, plants are able to cool cities during the summer. In the process of evapotranspiration, plants use heat energy when evaporating water. This process cools the air to reduce the 'Urban Heat Island Effect' in the summer, which is mainly due to the expanse of hard and reflective surfaces, such as roofs, which absorb solar radiation and re-radiate it as heat. Green roofs are more effective than cool roofs because cool roofs reflects sunlight onto neighboring buildings and heating their wall surfaces.

Improves the Life of Residents 

Providing real "green lungs" for the city, the green roof helps to combat pollution; plants release oxygen, absorb carbon dioxide and filter out dust suspended in the air. Bringing back nature into urban environments also integrates buildings more successfully in their environment: the city is more attractive and city dwellers are better able to enjoy their surroundings. Installation of a green roof can mitigate a significant amount of CO2 emissions. A 10,000 square foot extensive system will capture over 800 pounds of C02 annually.

Encourages Biodiversity

Although green roofs cannot replace a habitat destroyed by development, thoughtful plant selection can enable green roofs to create new wildlife habitats for pollinators, birds, insects, and even small animals. Drought tolerant plants selected for green roofs provide a wide variety of vegetation and biodiversity. Even though the selection for ground cover is composed of primarily sedums, there are hundreds of sedum varieties, and a sedum-mix can be very diverse.

By reintegrating green spaces into the urban environment, green roofs restore ecological functions damaged by urban development. The layer of growing medium, the range of plants suited to the local climate, and shelter areas created by the micro ecosystem all encourage the return and development of plants and animals in the city.

Facebook TwitterLinkedinChaine You Tube
As an expert in green roofs, Vegetal i.D. is a member of:

adivet association des toitures végétales   GRHC-white-no-background-copy-smaller Milwaukee Water Council AIA-provider-logo

US Green Building CouncilPole Dream, Pole de compétitivité eaux et milieux - région CentreGreenroofsGTTV Conseil GTTV 

Looking for a product to achieve a successful green roof or achieve your on-site stormwater management goals? As experts in green roof and stormwater management products, Vegetal i.D. is a manufacturer and provider of green roof and stormwater management solutions.  Vegetal i.D. stays with every project from concept to installation so with Vegetal i.D. your never on your own.

Vegetal i.D. offers modular extensive green roof products such as Hydropack®, stormwater management solutions and green roof solutions for any pitch using Acropack.