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| What is a Greenroof? |
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| Summarily, greenroofs are vegetated roof covers that take the place of bare membrane, gravel, shingles or tiles. There are many variances of greenroof types, but the all greenroofs include at least a single to multi-ply waterproofing layer, drainage, growing media and the plants. |
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| Two Types of Greenroofs |
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Extensive: |
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These roofs are low-profile and include fewer layers. They are less expensive and require very little maintenance. Extensive greenroofs can be constructed on slopes up to 30 degrees and steeper ones can be installed with raised grids or laths to hold plants and soil media in place. |
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Intensive: |
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These roofs look like traditional gardens because a much wider variety of plant material can be included since growing media depths are increased. |
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| Greenroof Maintenance |
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Extensive: |
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Greenroofs require watering occasionally during the first year of establishment. If you have chosen the correct drought tolerant plants wisely for your area, except in extreme periods of drought, they do not require watering. |
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Intensive: |
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Greenroofs need to be treated like gardens. High winds are especially drying, so Intensive Greenroofs require a bit more water than ground level gardens. Usually large intensive Greenroofs have an irrigation system installed. |
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| Why go Green? |
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| THE DIRECT, PERSONAL, BENEFITS |
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| Lower Your Bills, Get a Tax Break and Increase the Value of Your Property |
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You cannot go wrong. Environment Canada found that a one-story building with a grass roof and 3.9 inches of growing medium could result in a 25% reduction in summer cooling needs. |
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| Make Your Business Visibly Eco-Friendly |
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| Public anger towards traditional “unecological” industries can be mitigated by a company’s environmental awareness as illustrated by their Greenroof. |
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| Longevity of Your Roof: |
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| While most roofs require replacement every 15 to 20 years, green roofs have a life expectancy of 30 to 35 years. |
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| Increase of Usable Space: |
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| Your roof does not need to be a useless surface. Greenroofs grant the potential for roof space to be an enjoyable atmosphere for anyone. Additionally, your building’s worth is heightened when it has a Green Roof. |
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| Aesthetics: |
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| Your roof no longer needs to look like a roof. Green roofs provide a natural looking environment that is both aesthetically and tangibly pleasing. Green roofs can also be designed in countless ways. |
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| Noise Reduction: |
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| The exact amount of noise reduction is hard to quantify and depends mostly on the thickness of the soil substrate and additional factors, but overall, up to a 50 decibel noise reduction can be realized (McMarlin, May/June, 1996). |
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| The Big Picture |
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| Improved Air-Quality: |
| Green roofs, because of their very nature (green), convert carbon dioxide into oxygen. |
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Through the process of photosynthesis, plants convert carbon dioxide, water and sunlight/energy into oxygen and glucose. This cyclical process supplies animals and humans with oxygen and food. (GreenRoofs.org) |
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1.5 m2 (16.15 ft2 ) of uncut grass, produces enough oxygen per year to supply 1 human with their yearly oxygen intake requirement. (GreenRoofs.org) |
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| Reduction of the Urban Heat Island Effect: |
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| Heat Island effect refers to the difference in temperature between a city and its surrounding areas. The difference can be as significant as 10 degrees. Green roofs combat the urban island effect due to the increased vegetation they bring to the urban landscape. Plants cool their surrounding environments through natural evaporation cycles. With more green roofs in the city and less, non porous blacktop, cities will cool down. |
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| Storm Water Retention: |
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| Green roofs retain up to 75% of a one-inch rainfall and therefore alleviate the pressure of the city’s sewer systems. Because green roofs retain more water, the amount of water that picks up dangerous particulates on its way to the sewers in lessened. Additionally, during storms, cities often combine their storm water with their household sewage waste due to the increased pressure on treatment plants. Thus, raw, untreated sewage is often released untreated into city waterways. |
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| Energy Conservation: |
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| Green roofs have the potential to reduce the ambient air temperature in a city. In addition to their contribution to lower temperatures during the summer months, and the subsequent lower demand for electricity, green roofs are provide important insulation during the winter months, once again resulting in a lesser demand for heat energy. |
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| Directly from GreenRoofs.org: |
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| Economic Benefits |
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Potential to reduce the size of HVAC equipment on new or retrofitted buildings (capital and operational savings). |
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Potential to reduce the amount of standard insulation used. |
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Potential to incorporate cooling and/or water treatment functions. |
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Potential for local, regional, and national market exposure, depending on the uniqueness of the project. |
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Potential to reduce or eliminate roof drains. |
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Potential to meet regulatory requirements for stormwater management. |
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Potential to reduce community resistance to new developments. |
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