The Green Roof Initiative, which Denver citizens voted for in November of 2017, would have required all new and existing buildings over 25,000 square feet to install a green roof. But the current law that was approved by City Council in October of 2018 focuses much more on cool roofs (roofs with a white reflective surface) and energy efficiency. So how did a law that focused on vegetative roofs become one that focused on the overall efficiency of a building?

After the Green Roof Initiative passed, it quickly became obvious that the language would have some unintended consequences. Therefore, a task force was formed to ensure a good compromise was met between private interests and local citizens. Although covering every roof on large scale projects with vegetation seems like a great idea, the reality is that is isn’t feasible or even beneficial for every single building in Denver.

For example, large-scale industrial buildings might or might not benefit from the energy efficiency of a vegetative roof in our climate, depending on how efficient the building already is. This is especially true for an existing building that needs to replace their roof. If the roof needs to have additional structural support, the original law would either require the owner to hire a structural engineer to prove that it isn’t cost effective (which is it itself a huge expense) or would have to foot the bill for a green roof and possibly not see any benefit. Whereas a cool roof could be a more economical way to replace the roof while still helping the city reduce its Urban Heat Island.

In addition, the original ordinance was very difficult to comply with overall. Many projects were on hold in the city due to the uncertainty and difficulty of the original language. So the task force, after many months of deliberation, created a new proposal that would instead mandate for cool roofs, and then have one additional compliance option (of which there are many choices). This new proposal would both allow Denver to mitigate the impact of the Urban Heat Island effect while also allowing it to be as easy to comply with as possible.

The City Council agreed, and voted the proposal into law in late October of 2018, almost an entire year after the original ordinance was voted in. This is how a green roof law became a green building law in the Mile High City.

Need help with your green building project or understanding the new compliance options? Contact Sow Green today for a consultation!


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