Green Roofs

 

An Ecologically Friendly Roofing System

Green Roof at BroccoloA green roof is a roof of a building that is partially or completely covered with vegetation and soil, or a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems.

Container gardens on roofs, where plants are maintained in pots, may also be considered to be green roofs. Rooftop ponds are another form of green roofs which are used to treat greywater.

Finally, the term "green roof" may also be used to indicate roofs that utilize some form of "green" technology, such as solar panels or a photovoltaic module. Green roofs are also referred to as eco-roofs, vegetated roofs, living roofs, and greenroofs.

Benefits of Green Roofing Systems

Green Roofing MaterialsGreen roofs are used to:

  • Provide amenity space for building users — in effect replacing a yard or patio
  • Grow fruits, vegetables, and flowers
  • Reduce heating (by adding mass and thermal resistance value) and cooling (by evaporative cooling) loads on a building — especially if it is glassed in so as to act as a terrarium and passive solar heat reservoir
  • Reduce the urban heat island effect
  • Increase roof life span
  • Reduce stormwater run off — see water-wise gardening
  • Filter pollutants and CO2 out of the air
  • The soil and plants on green roofs help to insulate a building for sound; the soil helps to block lower frequencies and the plants block higher frequencies.
  • Filter pollutants and heavy metals out of rainwater
  • Increase wildlife habitat in built-up areas

A green roof is often a key component of an autonomous building.

A 2005 study by Brad Bass of the University of Toronto showed that green roofs can also reduce heat loss and energy consumption in winter conditions.

In a recent study on the impacts of green infrastructure and in particular green roofs in the Greater Manchester area, researchers found that adding green roofs will help keep temperatures down, particularly in urban areas: “adding green roofs to all buildings can have a dramatic effect on maximum surface temperatures, keeping temperatures below the 1961-1990 current form case for all time periods and emissions scenarios. Roof greening makes the biggest difference…where the building proportion is high and the evaporative fraction is low. Thus, the largest difference was made in the town centres.”

Source: Wikipedia - http://en.wikipedia.org/wiki/Green_roof