Denver is the latest city to mandate rooftop gardens or solar installations on new, large buildings, joining San Francisco, New York, Paris, London and other cities around the world with similar green roof measures, the Associated Press reported.
The Colorado capital ranks third in the nation for highest heat island and eighth in the nation for worst ozone/particulate pollution, according to the Denver Green Roof Initiative, a grassroots group that advocated for the city’s green roof ordinance, Initiative 300.
Although the official tally is not in, the ballot initiative had 54 percent approval as of Thursday, signaling that the measure is headed towards victory. The vote will be certified on Nov. 24.
Initiative 300 creates a new building code that requires green roofs or solar panels for most buildings 25,000 square feet or larger that are constructed after Jan. 1, 2018.
The Associated Press noted that the measure is more stringent than other green roof mandates, as it requires many existing buildings to be retrofitted with green roofs when the old roof wears out. Older buildings that cannot support the load of a green roof can get an exemption.
“These required building improvements would significantly reduce long term operating costs by lowering energy consumption and increasing the longevity of a roof,” the Denver Green Roof Initiative stated on its campaign website. “A green roof lasts 2-3 times as long as a traditional roof because the waterproofing membrane is protected from damage by the elements and workers by covering it with a growing medium and plants.”
The measure did not have an easy road to passage. Denver Mayor Michael Hancock opposed the initiative over worries that it could drive up the costs of construction projects. Also, several Denver businesses spent $250,000 in an advertising push against the plan.
Department of Community Planning and Development spokeswoman Andrea Burns told the Denver Post in March that the department would prefer to give architects and engineers “the flexibility to design a roofing system that works best for their needs and their budgets.”
Following the vote, however, Burns conceded to CBS4 that “it will be a little bit of work in the next few weeks, but green roofs are already possible in Denver. It’s just a matter of making those agreements that are part of Initiative 300 work with our system now. We’re going to make this work for the people of Denver.”
The Denver Green Roof Initiative admits that green roofs cost about $15 more per square feet than a traditional black roof but pointed out that the green roof will pay for itself in about six years.
“Even though the extra cost would be offset in as soon as 6.2 years, most developers choose not to incorporate them because they build the building then sell it,” the group said. “They don’t see those energy and storm-water savings. They don’t save the money from roof longevity. Yet they are still able to sell the building for more money with these improvements!! We believe that the developers of Denver could be doing more to negate their footprint in our beautiful city. We believe green roofs are the answer.”
The initiative was endorsed by green builders and environmental groups.
“Initiative I-300 will contribute to improving Denver’s air quality, increasing the energy efficiency of its buildings, mitigating the urban heat island effect, managing storm water runoff, and creating habitat for pollinators and other insects,” said Lauren Petrie, Food & Water Watch’s Rocky Mountain Region Director. “We are dedicated to a more sustainable future in Denver and believe that passing this green roof initiative will be a vehicle for asserting our human desire for cleaner air and water, and cooler urban temperatures.
The Denver Green Roof Initiative stressed in a Facebook post Friday that even though Initiative 300 passed, there are still “tremendous hurdles to overcome due to push back from those in power.”
“This is a battle won against climate but the war doesn’t stop here,” the post stated. “We must all get active and fight for our values, because we are stronger together. Thanks again for the overwhelming support. The citizens of Denver have a healthier, more sustainable future because of YOU!”