‘This is a wonderful book that should be on the desk of every architect and planner. It shows how

Increased roof longevity and reduced maintenance costs
: The most vulnerable 
layer of any roof is the waterproofing course, which degrades over time due to exposure of the 
elements. Eco-roofs greatly protect these buried membranes from extreme wind, temperature 
fluctuations, damaging ultra violet rays and mechanical injury. European eco-roofs have been 
around from 40 to 75 years or more and when properly installed with high quality materials, 
they can double the roof longevity and functionality. Major eco-roof providers commonly issue 
a 20-year assembly warranty and performance guarantee.
Reduced energy consumption and costs
: Thermally insulating eco-roofs offer energy 
savings through reduced energy usage in varying degrees based on geography, number of 
storeys, system type and depth of the soil substrate. A 2000 report found that in general 
savings of up to 50 per cent of cooling costs and 25 per cent of heating costs could be achieved, 
at least for the floor directly below the eco-roof.
5
A 2003 study found the Seattle Justice 
Center is saving as much as US$148,000 each year due to its eco-roof.
6
Increased developable space
: Eco-roofs can significantly reduce the size of, or even 
completely eliminate, the costly and unattractive large tracts of land necessary for retention 
ponds. 
 
As a stormwater management measure to offset permeability requirements, some cities 
extend density bonuses to developers who use eco-roofs (instead of impervious rooftops), 
resulting in higher floor-to-area development ratios. Currently Portland, Oregon, and Chicago, 
Illinois, offer developers increased floor area within the Central City, depending on eco-roof 
coverage in relation to the building’s footprint.
Reduction of stormwater infrastructure
: The need to capture, slow down and then 
release urban runoff is necessary in every municipality, and eco-roofs are considered to be a 
low impact development solution since they manage stormwater on-site. If applied on a large 
scale and treated as a stormwater infrastructure ‘best management practice’, eco-roofs could 
feasibly lower the overall costs of stormwater rehabilitation in our cities through reduced 
replacement of conventional elements such as drains, pipes and sewer lines.