Intro To Green Roofs, Part 1 Of 3: What Is A Green Roof, And Why Do I Need One?
The History of the Green Roof
Image: Vincent Callebaut
Amongst the memes and cat pics on your social media feeds, you may have also seen pictures of futuristic or fantastical looking buildings utterly wrapped in greenery and topped with a green roof. Such buildings are no longer, nor have they ever been, limited to fictional Tomorrowland or Hobbiton. Firstly, planted, green roof gardens have been around for thousands of years, the first being the Hanging Gardens of Babylon constructed around 500 B.C. The green roof technology of today packs a high ROI and array of benefits for all types of building owners: commercial, residential, industrial and institutional.
Into the late 1800s, sod roofs were the most commonly used roof type on log houses in rural Scandinavia, as they were excellent natural insulators, keeping homes cool in summer and warm in winter.
Photo: Alan Burchell
The concept was overhauled in 1960s Germany making use of modern technologies resulting in systems vastly more efficient than their early model releases. Since then, these ‘green roofs’ (a.k.a. eco-roofs or roof gardens) have spread to many regions of the world.
What is a Green Roof?
The over-simplified answer is this: A green roof is a system of layers that are installed on top of a typical roof, to support soil and plant growth.
A further explanation of each layer and its function can be found below, but first let’s explore the answer to ‘Why Green Roofs?’
Why Green Roofs?
Image: Scientific American
While still not yet as widespread as they are in Europe, green roofs are becoming increasingly popular in urban centers across North America and Asia, and many factors are driving this demand.
Green roofs are a veritable Swiss Army Knife of benefits spanning health, property values, quality of life, the economy and the environment.
Swiss Army Green Roof
And just like two people may be interested in totally different tools on the same Swiss Army Knife, different organizations and building owners are attracted to different benefits and features of green roofs.
To be continued…
For this reason, to encourage green roof construction, several North American cities (ie: New York, Philadelphia, Toronto, Chicago) offer very generous financial incentives, property tax rebates and cash reimbursements. City governments love green roofs for these public benefits:
Stormwater retention (easing of street flooding and sewer overflow)
Cooler air (reduction of Urban Heat Island Effect)
Natural habitat for animals and plants
Cleaner air (reduction of pollutants, dust and smog levels)
Local job creation
Waste reduction
Aesthetic improvement
To be continued…