On Nov. 8, 2017, the voters of Denver passed the Denver Green Roof Initiative. As of Jan. 1, the construction of any building with a gross floor area of 25,000 square feet or greater must include covering a portion of its roof with vegetation, solar panel installations or a combination of both. The Initiative is codified as Article XIII §§ 10-300 et seq. to Title I, Chapter 10 of the Denver, Colorado Code of Ordinances.
Supporters of the initiative assert the new requirements will mitigate Denver’s growing ozone/particulate pollution output and alleviate Denver’s “urban heat island” effect, a condition in which an urban area becomes significantly warmer than its surroundings due to development density and a heavy concentration of heat-retaining pavement and concrete. Supporters contend the “improvements” will reduce long-term operating costs and overall energy consumption through the use of solar power and offsets to costs and energy currently devoted to water drainage. Additionally, supporters claim the rooftop vegetation will extend a roof’s longevity by providing added protection to its waterproofing membrane.
The initiative passed despite heavy opposition from powerful local actors including Mayor Michael Hancock, the Denver Metro Chamber of Commerce, the Downtown Denver Partnership, the Visitors Bureau and development groups. These groups insist the initiative will drive up development costs and contribute further to the overvaluation of Denver’s housing market. Mayor Hancock expressed concerns that the initiative’s mandate-only approach eliminates opportunity to implement a phased infrastructural plan aimed at addressing environmental concerns that could ultimately yield more effective long-term results while avoiding the repercussions the initiative currently poses to developers and property managers. The chairwoman of Citizens for a Responsible Denver, a coalition of Colorado businesses opposed to the initiative, said she is troubled by the fact that institutions like Denver Health might now be forced to spend less on, or postpone indefinitely, future projects such as expansion or the construction of a new facility to pay the costs required to satisfy the initiative’s requirements.