Calgary is home to Eighth Avenue Place, a brand new twin office tower built on the former site of Calgary’s historic Penny Lane Mall. News yesterday confirmed that this new build will be home to Canada’s largest ‘green roof’, coming in at a massive 30,000 square feet.
Because of this feature, as well as numerous other green credentials, this building project has been pre-certified as LEED Platinum – only the second building to earn such status in the whole of North America!
A green roof is simply when the roof of a building is partially or completely covered with vegetation. As concerns about our built environment grow, the various benefits of green roofs are making them a popular choice for any new build. In built up areas, a green roof is particularly good at combating the heat island effect – a surprisingly small concentration of green roofs in an urban environment can actually lower a city’s temperature during the hottest months of the year. Green roofs are also useful for absorbing rainwater and controlling temperature (warmth in the cold months and cool in the hotter months).
The University of Toronto published results in 2005 that showed just how worthwhile a green roof is; for example, it can reduce cooling loads by anything from 50 per cent to 90 per cent.
Interest in green roofs has grown dramatically over the last 10 years and Canada is one of the leading research countries. However, the actual concept of green roofs has been around for centuries, particularly in Northern Scandinavia where they are known as sod roofs. Several different types of green roof have been developed around the world, and range from ‘intensive’, through ‘semi-intensive’, to ‘extensive’. These different types refer to the depth of planting material and the amount of maintenance needed to keep the roof functioning well.
‘Intensive’ roofs will often have actual green features growing on them, such as shrubs or herbs, whereas ‘extensive’ roofs are more likely to look more like a simply field with a thin layer of moss or grass.