The green roof-sustainability trend of which we hear today was started in Germany in the 1960s. An estimated 10% of roofs in Germany have been “greened” (according to Wikipedia). Other European countries have come along on the progression.
The benefits of these roofs of vegetation are as follows: they absorb rainwater lessening runoff, they provide insulation—both temperature and sound, and they act as filters for pollutants. And without deleterious effects of extreme changes in temperature that traditional roofs have, they last much longer.
Cities are generally four degrees hotter than surrounding areas—green roofs are reported to lower this urban “heat island” effect. Prepared roofs provide agricultural options. And in some places they also create a habitat for wildlife. I’m picturing delightful birds hopping about overhead and pollinating bees. And of course there’s the visualization of the adaptive squirrel population stashing nuts in sod and moisture membranes instead of under the shingles.
There are currently over 20,000 pounds of soil and plant material on top of the Tufts University’s Tisch Library in Boston where the Office of Sustainability Green Roof Initiative was founded in October 2006. Other universities in the U.S. are also experimenting with these initiatives.
Nancy R. Peck